Marine Models: Volume 9, Number 11 – February 1937

or orm ECHNICAL, = —_—-2.. 3 —-. – —_ ere —) j INCORPORATING THE MODEL YACHTSMAN Vol. IX, No. 11. Published on the Seventh of each Month BETWEEN February, 1937 OURSELVES By THE MANAGING DIRECTOR, MARINE MODELS PUBLICATIONS, LTD. HE large number of readers of MARINE Mopets who have so readily and whole-heartedly assisted in response to my article in the December issue will be pleased to know that our circulation has been slowly but steadily rising since the article appeared. While it is true that we have not exactly been inundated with orders, there has been a steady increase, and for this the Directors are naturally very grateful. Particularly are they thankful to those Club Secretaries who have been actively canvassing their members on behalf of MARINE MODELS, and to one in particular—whose name | have not got permission to mention—who has not only managed to secure eight new subscribers, but has also collected and forwarded the subscriptions. This is practical help of the right kind! We have still a long way to go before we can consider ourselves out of the wood, but we do feel that a start has been made in the right direction, and we hope our readers will not only sustain but redouble their efforts on behalf of MARINE MobELs. We are also making renewed efforts to secure additional advertisers, and have already received promises of support from Clubs who intend to advertise their special events in MARINE MODELS. Readers can help considerably in this connection by saying, when purchasing anything advertised in our columns, that they saw the advertisement in MARINE MopELs. And so, believing that the interest of readers has been aroused, and knowing that their goodwill (which is far more valuable to us) has been secured, the Directors are encouraged to feel they are well on the way to achieving Suggestion No. | (to increase the number of readers). That being so, Suggestion No. 2 (to increase the price of the Magazine) is being deferred pending the final results of the appeal for increased sales and club advertisements. As to Suggestion No. 3, we shall be able to dis- miss it from our minds if only we can maintain the present rate of progress. The numerous suggestions received from interested readers have not only been welcome, but helpful, and wherever possible they will be acted upon as opportunity occurs. Readers can rest assured that we shall do our part if only they will continue to extend their practical goodwill. The Editor has plans for considerable developments and new features, which will be of interest to readers, but it is not possible to commence them until the revenue has risen sufficiently to warrant the additional outlay and increase in size of the Magazine. bs 308 MARINE MODELS SIMPLE NAVAL ARCHITECTURE FOR MODEL YACHTSMEN & MARINE MODELLERS By YARDSTICK (Continued from page 284.) | N my last article I used the terms Relativity and Similitude. I should have mentioned that these were borrowed from the late Norman Skene’s works. I tried to think of a fresh expression to cover them, but could think of nothing more apt. Some of the Expressions given in my Table are the same as those in Norman Skene, but others are different. In any case, all of them are well known to naval architects generally. To the beginner the expression “ D?”” may require some slight explanation. The Displacement D is always taken in cubic inches (or feet for full-scale vessels), and the usual basis for comparison is /D. Thus /S may be used as a basis of comparison with the #D. Another way of expressing the same thing is to compare S with D’. Stated mathematically, D* is the Cube Root of D raised to the second power. For example, if D=1728, “/D=12, and D*=(12)? or 144. And now for the question of waves made by the vessel herself. A vessel floating in water displaces a volume of water having a weight equal to her own. As she moves forward she pushes the water aside to make room for herself, and behind her the water flows in to fill the hole left behind her passage. The forward part of the craft up to the greatest section is therefore displacing the water, and the part from the greatest section aft is replacing the water. These two parts are known as the “ Entry ”’ and “ Delivery.” If the reader will turn back to Fig. 6 (December number of MARINE MoDELs), and study the Curve of Areas shown and consider that it represents the volume of the section areas throughout the boat, he will understand that this curve graphically shows the “ Rate ” of the Entry and Delivery. Now the Entry, in pushing the water aside, sets up a wave system. Likewise, the Delivery, in replacing the water, sets up a second system of waves. When we see a boat that is very sweet through the water, she leaves scarcely a ripple to make her passage. The reason of this is that the Entry wave and the Delivery wave have cancelled out each other. In fact the crest of one has dropped into the trough of the other and exactly filled it. Put in another way, the bow and stern of the vessel exactly match each other. To accomplish this desideratum the ends of the boat must match in rate as well as in volume. This would seem to imply that the Entry and Delivery should be of equal length, but as a matter of fact the Entry requires to be a trifle longer than the Delivery as the inertia of the water has to be overcome, while the Delivery deals with water that has already been set in motion. In the case of a vessel with a parallel middle body (such as a liner), the rate over the parallel middle body neither increases nor decreases. It is, in fact, a sort of neutral zone between the Entry and the Delivery. Although we motion, it will visualise things being at anchor know the vessel to be in possibly make it easier to if we consider the vessel as in a tideway with the water flowing past her. Having grasped the principle of the Entry and Delivery, let us consider the case of a yacht running before a stiff breeze on an even keel. Suppose her bows rise and the stern squat, what is happening? The Entry is obviously not displacing the water as fast as the Delivery is replacing it, so there is in- sufficient water to fill the hole caused by the boat’s passage, and the boat drops down into the hole. I mention a yacht particularly in this connection as in a power-driven craft this may be affected by the propeller. From this we deduce that the greatest section is too far forward, and this, of course, means that the C.B. is too far forward also. If the boat tends to. stoop and lift her stern under these conditions, the reverse is the case. The speed of waves is governed by their length (i.e., measured from crest to crest), irrespective of height. A wave system 20ft. long is slower than one 40ft. long. The ratio is as the square root of their length, which in the present instance would be as /20: \/40. Experiment has shown that the primary feature of hull design which makes for speed MARINE is length. Therefore in order to get the fastest possible hull:on any given length overall, the boat should be designed so that the crest of the entry wave is as far forward as possible, and the crest of the delivery wave as far aft as possible. Thus, the boat travels in the trough of these two waves and makes the utmost possible use of her length. If we compare a 20ft. boat with a 40ft. boat, their speed ratios should therefore be \/20: V 40, just as those of the 20ft. and 40ft. waves. These remarks apply with equal force to sail- and power-driven craft, so long as the latter are of the “ Displacement ” type. With MODELS 309 leen,” is built, she is given 1,500 sq. in. of sail, and, of course, makes rings round “ Eileen.” But this extra sail has made “ Kathleen” a I2-rater, so to take her on the owner of “Eileen” builds a 12-rater, but as he is designing for a 12-rater he makes his new boat, ” Maureen,” 52.5 waterline and 1,371 sq. in. of sail. He beats “‘ Kathleen,” but again has an under-canvassed yacht. It will therefore be seen that the art of the designer ‘is to select dimensions that will give the fastest possible boat under any given rating formula, and that it is a misnomer to say that a boat is really fast unless one implies that she is fast in consideration of the conditions she has to comply with. hydroplanes (whether stepped or stepless) a different set of conditions is introduced. The general use of the Speed-Length ratio is for comparison of speeds of vessels of different sizes. Let us take two rather ex- have seen that the fastest yacht on any given length is one with the crest of the 1,000ft. and a speed of approximately and treme examples. A liner with a waterline of knots has a speed figure of : — 314 31.5+/1,000 = 31.5 + 31.62 = approximately | On the other hand an A-class medel yacht has a waterline of 4ft. and a maximum speed of about 3 knots, so her speed figure is :— 3+ 4=322=14 We therefore see that the liner is by no means a fast vessel for her length. A lot of humbug is talked about streamlining. Streamlining at the low speeds attaine d by ordinary waterborne craft (other than fast hydroplanes) is a very different matter from real streamlining such as is required for fast planes or racing cars. As speed tises, the Entry should shorten in proportion to the Delivery, but the designer of model yachts or ordinary power-driven craft need not trouble his head about this, since even if he attains comparatively high speed-length ratios, his actual speeds will be low, and both water and aw retain their full-scale density, One often hears a yachtsman (or model yachtsman) say that a certain boat is fast, but actually this is a rather loose statement to make, and a boat’s speed is of necessity limited by the rating rule she is built to. To the experienced this statement will be perfectly intelligible, but for the beginner it may require some explanation, so let us once again work out a little example. Suppose the 10-rater “Eileen” (LWL 48, S.A. 1,250) proves the crack boat in her club, she is acclaimed as a fast boat. In practice, however, a boat of this size is really under-canvassed with only 1,250 sq. in. of sail, so when a sister boat, “ Kath- Now let us return to our waves again. entry wave the as crest. far of forward the as_ delivery We possible wave as far aft as possible. Moreover, the trough should make a nice hollow for the belly of the boat to sink into, and thus permit her to use the maximum of her overall length. By watching a boat carefully, as she sails, we can see how far she fulfils this condition. First observe her from the windward sailing closehauled. Here the waterline should show the crests of the entry and delivery waves well placed and a bold hollow between, the water flowing snugly along the hull. From the leeward, when close-hauled, the waterline should appear practically straight, except for local dis- turbance, caused by the bow wave. When running, the wave either side should show the crests of the entry and delivery waves and a hollow (though not so deep as when closehauled), and the boat settling down nicely into the water to use her full length. The old type of rater used to plane when running in a heavy wind, and appeared to go a tremendous speed. Undoubtedly she did accelerate to a certain extent, owing to reduction in displacement and wetted surface under these conditions, but she did not really travel as fast as one used to think, and a boat that settles down to use her length under these conditions will be faster, make less fuss, and be more controllable. I saw a good instance of this one morning at Kensington. One of the old type 10’s (and a good one at that) was sailing against ‘ Vivix,” a long, lean boat, notably clean through the water. The old boat sat up and planed at apparently tremendous speed; “ Vivix,’” using her length, made — 310 MARINE no fuss and hardly appeared to be travelling, but was drawing away all the time, beating the other handsomely. If the reader thinks the above out, and then studies a few boats sailing, he will soon begin to draw correct deductions from watching the wave-throw of different hulls. I can assure him it will help him immensely in either selecting a yacht or designing one. In addition to these major systems of waves created by the boat herself, there are several minor systems. One of these is the Bow Wave, made by the cutwater. In a yacht running, or a powerboat, this piles up on both bows, but more to leeward than on the windward side. In a yacht close-hauled, the Bow Wave is all to leeward. The Bow Wave is governed by the speed, fineness of a vessel’s bows, and in the case of the Lee Bow Wave by the amount of leeway she is making. If there is a very heavy pile of water under the lee bow, it will tend to set the boat’s head up to windward, or, in other words, make her hardmouthed. It should be noted that it is quite possible for a badly designed boat to be heavy on the helm and yet make far too much leeway. I say “far too much” advisedly, since every boat makes a certain amount of leeway. There is yet another system of waves in a sailing vessel to be considered: that set up in the lee garboard, when the boat is closehauled. In considering the water flowing through the hollow of the lee garboard, we have to remember that the pressure in this part is increased by the leeway, which every boat makes. That means that the Delivery in this part of the boat has to be rather longer than elsewhere in proportion to the Entry, as there is more water to deal with than that provided by the Entry. It behoves the designer, therefore, to make the run through the garboards long and easy. Some designers, particularly of models, dodge this problem by making the whole garboard over-slender, but in so doing they lose displacement and possibly spoil the symmetry of their sections. A choked garboard will have the effect of pushing the stern up to windward. We have all of us seen a model, sailing nicely to windward, suddenly bolt when an extra puff comes. What has happened is that she has been trimmed so as to counteract the pressure in the after-part of the lee garboard, but as her speed rises with the heavier puff, the pressure rises and throws the trim out. It should be added, however, that this is by no means the only cause of a yacht’s bolting under these condi- MODELS tions, and a badly balanced hull is equally likely to be the cause of the trouble. In many yachts with short keels or finand-skeg, there is a heavy bubble of water under the stern from water escaping from the lee garboard, and in some fin-and-skeg boats it will boil and throw a feather up, even showing to windward. This escape has undoubtedly mitigated the evil, but a more efficient Delivery in the lee garboard would have been better still. The yacht designer has not to consider the effects of the propeller (or propellers), but this is an important point for the powerboat designer. The propeller does its work by sucking a stream from ahead and impelling it astern. The water sucked from ahead is the ‘feed stream,” and that impelled astern is the “jet.” The front side of the propeller blade actually does more work than the after side, so the feed stream is most important. If the propeller is placed so that the hull or deadwood chokes the feed stream, the propeller will not get enough water to feed the jet, and so cavitation will occur. Cavitation is when the propeller has pumped the water away and is revolving in a vacuum. Of course, there are many other things liable to cause cavitation, and this subject includes propeller design and size, speed at which it runs, engine power, etc. | However, we are at present dealing primarily with hull design. What is known as “ propeller suck”’ often causes a vessel to squat, but what is really happening is that the feed stream is robbing the Delivery of water to such an extent that a vacuum is formed, and the vessel settles down into it. The cure is to reduce engine power, fit a less powerful propeller, and minimise the feed stream. Alternatively, if it is wished to use as much power, to make the hull coarser aft so that the boat fills the vacuum without squatting. It is, however, obvious that squatting is caused by over-driving a hull, and the correct course is to design the vessel for the speed required, and then fit an appropriate engine and propeller. Alternatively, for vessels like tugs, where power is more important than speed, the hull must be designed to stand the designed engine power. Naval Architecture consists of knowledge of a few simple physical facts and common sense in applying these principles, coupled with a modicum of simple mathematics. Forethought, patience, experience and care are. however, essential to produce a successful design, MARINE Much, in fact the greater part, of naval architecture applies with equal force to either model yachts or model powerboats, but here and there, as the garboard wave system and the propeller throw, isolated facts apply to one section only. Yet even to a specialist a little general knowledge outside his particular sub- ject does not come amiss. On the other hand, even if one does specialise in, say, model yachts, it is a great mistake for the designer to interest himself in one class only. For instance, study of the problems of propelling a big hull with little sail, under the A-class rule, was really the cause of the alteration in type of the 10-rater from the scow to the long waterline boat, which undoubtedly is an improvement. for this The designers mainly responsible change design to various classes. ‘“Leonora’’ was among the first 45in. waterline 10-raters to be published, and “ Evadne” almost the first of the present 48-50in. | What applied in this case, applies with equal force to the other classes, and a designer who always works at the same class gets in a rut and tends to become stereotyped. He may turn out a good boat, but is unlikely to do work displaying real originality. By working under several different rules, the designer acquires a knowledge of the true values of the different speed factors, which he ‘would not do if he invariably designed under the same rule, owing to the cramping effect of every rating rule on certain dimensions. With this knowledge he may find where it will pay to break away from the generally accepted type under any particular rule. To the beginner much in these articles ma appear rather advanced, but if he will take the trouble to follow things out, I think it should all be clear. On the other hand, many readers may not wish to delve too deeply into naval architecture, but prefer to leave this branch of the subject to specialists. I suggest that these should read these articles, concentrating on the general facts stated. It will add to their pleasure to know why boats perform as they do, and assist them to handle their craft better. Propellers have one or two points in com- mon with sails, however. As mentioned in the paragraph on propellers, the back of the blade does less work than the forward side. Similarly, with sails, the forward side does more work than the after side. Again, with propellers, the leading edge of the blade does the greater part of the work, while with sails it is the luff that is the most efficient part MODELS 311 of the sails, particularly to windward. This is all governed by what is known as the shift of pressure towards the leading edge, and as this also has a great effect on the design of keels for sailing yachts, we might as well get a grasp of the principles of this law. This law came into prominence as a result of experimental work in aeroplane design, and yacht designers owe quite a lot of the recent progress made to this source. The easiest way to explain this natural law is to take a simple example. Think of a leaf falling from a tree on a still autumn day. It gently zigzags down. Analysing its downward progress, we notice that it first makes a swoop to, say, the left. At first it travels at quite a steep angle, but gradually flattens out until it becomes horizontal. Then the rear edge drops lower than the front edge, and the downward swoop is arrested. Then comes a swoop to the right, and what has been hitherto the rear edge be- comes the leading edge. The same thing happens, and the leaf’s downward swoop to the right is, in turn, arrested. And so it swoops, first left, then right, until the leaf comes to rest on the ground. Drop a plate overboard from the deck of a yacht and watch it as it gradually goes to the bottom. Once again its downward pro- gress will be zigzag in a series of swoops. What has actually happened? What has actually happened is that the leading edge, en- countering undisturbed air (in the case of the leaf), or water (in encounters greater the case resistance of the plate), than the rear edge, so pressure develops at the leading edge. This increases until it becomes sufficient to check the downward swoop, and the leading edge rises above the rear edge. The motion is arrested, and when the leaf or plate starts to fall again it naturally goes in the direction of the lower edge. The faster the leaf or plate falls, the greater the tendency to develop pressure at the leading edge, and so the centre of pressure shifts more rapidly towards the leading edge. This law explains why the leading edges of the blades of a propeller do most of the work, also why the Centre of Effort of sails moves forward as the vessel sails, and why the Centre of Lateral Resistance of a keel or fin moves forward when the vessel is under way. [ shall have occasion to refer to this again later on, but the beginner should grasp the principle and remember it, as it has great influence on his work. he 312 MARINE When he is designing a racing yacht, it is the designer’s business to turn out the fastest possible boat allowed by the rating rule he is working to. No rating rule in existence is ideal, and in consequence racing yachts are by no means ideal in every respect. The only other consideration for the designer is to turn out a balanced design. Two articles on balancing a yacht design were written by me for MARINE MODELS, and appeared in the numbers of January and February, 1936, to which I refer the reader. The designer of model power craft is also referred to these numbers for an explanation of the principles of stability and the Metacentre. Under all rating rules for model yachts, except the 30in. and 36in. Restricted classes, sail area is a heavily taxed factor in the formulz, and, consequently, in order to get the longest possible hull, the designer is obliged to under-canvas his boats. An important consideration is the amount of wetted surface, particularly when a yacht is getting to the upward limits of a class as regards size of hull with a consequently reduced sail area. Wetted surface calculations take time, but are not difficult, and wetted surface area is another useful point to note in our tables of dimensions, which we should keep as a guide to selection of dimensions for future designs. The method is to measure the periphery of the under-water parts of the sections, and calculate the area by the Trapezoidal Rule. This rule was explained in the December number of MARINE MopeLs. The interval between the sections cannot simply be taken as that between the section stations, as we are dealing with the skin, and the intervals measured round the skin are greater and vary. A bilge diagonal must therefore be drawn, having its forward and after ends at the L.W.L. endings, and plotted in its own plane. Measure this diagonal and also the L.W.L. on the L.W.L. plan. The interval (taken from section stations) is then, multiplied the interval by the length of the bilge diagonal and divided by the length of the L.W.L. The corrected interval is generally about 2 per cent. greater than the section spacing. One point to remember is that if working from a scale plan the wetted surface area found must be multiplied by the square of the scale to get the full-scale area. A lot of rubbish is talked (and for this some of the older text-books are largely to blame) about the Centre of Lateral Resistance, Centre of Effort, and “‘ Lead” (i.e., distance the C.E. MODELS is ahead of the C.L.R.), so we may as well consider these two centres. The Centre of Lateral Resistance is the C.G. of a plane surface, having the same profile as the underwater body of the vessel. Now the body is not a flat surface, but a more or less saucer-shaped body with a plate appendage (or keel) underneath it. Obviously the plate presents more resistance to lateral motion than the saucer. What this difference amounts to depends on the exact shape of the body and the relative areas of body and keel. Let us suppose that their respective powers of resist- ance are as 3: 5. Now when the vessel starts to move, the stream of water flowing past increases its resistance to sideways motion, and the faster the vessel moves the more this increases. Let us suppose that the resistance is increased as the square of the area. Then the respective values of the hull and keel would be as 9: 25, which would mean that the resolved centre would move downward towards the centre of the keel. We therefore see that the C.L.R. moves its position as soon as the vessel gets under way, and continues to move in accordance with the speed developed. Nor is this all, since we know that there is also the shift of pressure towards the leading edge to be taken into consideration. In accordance with this law, both the C.L.R. of the body and that of the hull move forward independently. The amount of this shift is also regulated by the speed through the water, and also by the angle of the leading edge to the water-stream. The nearer this is to a right angle (i.e., the nearer perpendicular the leading edge is) the greater the amount of shift. All we actually know, therefore, is that the effective C.L.R. is not the calculated C.L.R., but some point below and forward of it. The C.L.R. is calculated by taking moments. To do this measure the depth of each section station below L.W.L. and list them. Multiply the first and last depths by 0.5 and list the functions obtained. Then multiply each of the products by its distance abaft the forward end, which gives the moments. Divide the sum of the moments by the sum of the products. The quotient is then multiplied by the interval. This is just as shown on page 266 of the December issue. An alternative method which is just as quick, and in the case of lateral area, even more accurate, is to trace the lateral plane on tracing paper and cut it out. The C.L.R. is ascertained by balancing on a pin-point. (To be continued.) MARINE THE MODELS TORONTO SOCIETY 313 OF MODEL ENGINEERS’ MEASURING APPARATUS FOR A-CLASS MODELS By L. G. BATEMAN (Hon. Secretary, T.S.M.E.) S recently reported in MARINE MODELS, the Toronto S.M.E. has recently acquired equipment for measuring its model yachts. Below is seen the complete equipment; the tank on the left for the water- time it has to be used. All the joints of the tank are tongued and grooved, and were painted with red lead immediately prior to being put together. After the overall length has been measured, the boat is put in the tank for measuring the freeboards. Two 1oz. weights, attached to threads hooked on the rigging, and passing over pulleys adjustable for height, gently pull the model up to a submerged knife-edge. When the water is still, after the model is placed in the tank, the knife-edge is adjusted so that it is just at the surface of the water; one of the adjusting screws is seen immediately S.W. of the measurer’s nose! A plumbline hangs from the extreme bow of the model and passes the edge of the horizontal scale, cut away to clear the models, but arranged so that its zero would be at the perpendicular through the knife-edge; thus the overhang is read directly. The boat is reversed in the tank to measure the overhang at the stern. The model in the second photo is “ Minnow,” A-class, built by John Harris. On the left is Gilbert Trout, and on the right Law- line determination holds some 80 gallons of water. It is 6ft. long by 22in. wide at the top. In the centre is the platform scale fer weighing the models, and, on the right, the dry measuring apparatus. The boats are the “ Silver Spray,” the hull of ** Ventura 3,” and ** Minnow.” The apparatus is kept in the garage of the Society’s Secretary, Mr. W. F. Choat, and, so that it may be moved to the centre of the garage for use, and to one side when not in use, the tank is mounted on 10 castors; it weighs some 900 lb. A brine solution is used, so that it cannot be emptied and refilled each rence G. Bateman. On completion of the overhang measurements the model is transferred to the drymeasuring machine, after the end supports have been set apart to the length of the L.W.L. obtained from the L.O.A. and the overhang measurements made. The support under the bow of the boat in the photo is the adjustable one. The boat is carefully centred, and the weight taken by the support under the keel, which support is levelled both ways by the spirit levels seen mounted on it, the whole machine having been previously levelled. The overhang device shows to better advantage in this picture and immediately in front of it, and on the book is the hydrometer used to check the specific gravity of the brine solution. The boat is ‘* Ventura 3,” by W. F. Choat. 4 THE COMPLETE MEASURING APPARATUS The model is correctly placed, fore and aft, by the plumbline against the scale seen projecting from the aluminium plate. 314 MARINE MODELS CLOSE-UP OF SHOWING OF MEASURING FORWARD Note height OVERHANG screws of TANK, METHOD for knife-edge, 40z. weights over pulleys forward until on adjusting also lines two passing that pull stem grounds on model knife-edge. The two long beams seen here and in the previous photo are for the measurement of the beam of the model; they rest on crosspieces at each end, and their upper surfaces are at waterline level. On the cross-pieces are mounted four short scales, two at each end with their zeros 12in. apart. The beams are adjusted one at a time so that they touch the boat, and so that the two ends are over the same reading on the scales; thus the beams touch the widest part of the boat. The reading for each beam plus 12in. is the beam of the boat. For taking the quarter beam measurements there is a double slider device, working in the slot seen milled in the plate which is attached to the upright supporting the model. The slider consists of two pieces of tin. x din. brass, silver-soldered together at right THE DRY- MEASURING MACHINE Note Q.B. Measuring Device at bow, also spirit levels on frame and Draught Measuring Platform. The waterline measurement gear for the tank is shown resting on the text-book ‘* Model Sailing Craft,’’ also Hydrometer for testing specific gravity of water in tank. angles, one of which works in the slot, and the other, which is graduated on its top surface, lies flat on the plate. On this piece works a ‘“U” sectional slider, carrying at its far end a vertically adjustable point, which is set with the calipers 1/10th beam distance above the L.W.L. level, which is the under-side of the plate. In use, the point is set 1 / 10th beam up, and the whole device set 1 /4th beam out from the centre-line by the scale engraved on the plate. The second and “ U”’ sectioned slider is then moved until the point touches the hull; if, as in the photo, it is the forward quarter beam measurement that is being made, the reading is made at the end of this slide; if it is the aft measurement then the reading is taken in the centre of the slot seen just behind the point. Both these measuring points are at ST MARINE MODELS 315 ‘CLOSE-UP OF FORE END OF DRY- MEASURING MACHINE —SHOWING METHOD OF Q.B. MEASURE- MENT Note the Plummet model tion Scale used to accurately on the machine, and set in posi- measuring also _— double Slider used to locate Q.B spots. their zero when the point is at the end of the waterline. The freeboards are taken from the top surfaces of the beams and the plate, due allowance being made for the thickness, ;;in., of the plate, and the draught is measured from the level of the tops of the beams to the top of the support under the keel, which is put at the lowest point on the keel. The value of this equipment was amply demonstrated, for of about 15 boats measured this year only three were within the A-class rating, though most of them had been built to published designs for A-class boats, adjust- ments having to be made either to the sail area, the displacement or the draught, which, strictly speaking, should not have been required, and we trust this has impressed the builders with the desirability of very accurately following the design to which they are working. [The Toronto S.M.E. are to be congratulated on the possession of such efficient and up-to-date equipment, which is better than that possessed by many M.Y. Ciubs. This article is particularly British timely in view of the remarks in Mr. C. O. Brook’s American Notes, which appear elsewhere in this issue. The importance of correct measurement is very obvious, is impossible. and without Clubs proper appliances, should, therefore, this provide themselves with proper gear to measure every class for which they cater.—Epiror, M.M.] WHAT’S T IN A NAME ? HE following is extracted from the Correspon- dence columns of our contemporary, Le Yacht. The writer of the letter, who is evidently a keen observer as well as a student of psychology, has noticed that yachts often bear girls’ names. Seeing in this the reason of frequent changes of name, he suggests that vessels should never be called after living persons. ‘* Really,”’ he writes, ** there are three points to consider: (1) One may keep both the yacht and the lady, and in this case there is, of course, no reason for changing the boat’s name. This, however, is almost idealistic, and of rare occurrence. (2) One may keep the boat and part with the lady. In this case it would not be natural if one did not wish to change a name that recalls unpleasant memories. (3) One may keep the lady and part with the boat. Although one has retained the original of the name for oneself, jealously-minded men might view with disfavour their old boat sailing under the loved name with a new owner.”’ He concludes, therefore, that yachts should bear neutral names such as those of fish, geographical features, etc., in the choice of which there is likely to be no question of masculine (or feminine) fidelity. 6-METRES DESIGN “LAVINIA ” ye have been asked by several readers about the crew weight for this model, as no mention was made either on the design itself or in our remarks about it. ‘‘ Lavinia”’ is, of course, intended to carry the 2 1b. crew weight (added after measurement in the form of internal ballast, as usual) like others of her class, and we did not think it necessary to draw attention to this. Half-size blue prints with full-sized body plan are now available from Marine MopELs Offices, price 15s., post free. E E EEIOS:;* ‘SOYSSSS S rr r r 316 MARINE SHIPS’ MODELS ARMAMENTS By A. P. Isarp, A.M.I.Mech.E. (Continued from page 286.) aE the fact that working models of guns HE writer’s attention has been called to would not generally be required by readers of our Magazine, owing to the fact that the scale of the models would only allow for guns about 4in. overall even on models up to, say, 6ft. in length, and that, therefore, particulars of working models might be out of place. Possibly there are some readers who may wish to produce working models, and to give them some encouragement the writer would say that he had a working muzzle loader of only lin. in length overall, which was fired realistically from a model brig by means of a small time fuse connected with the touch-hole. A whole broadside of guns could be fired electrically with a small dry battery and sparking coil, placed in the hold of the ship, the guns being wired accordingly, and the contact made by means of simple clockwork. Another point is, that the very interesting drawing reproduced in our December issue is that of an 18-pounder carronade, and that we have mentioned that 18-,24- and 48-pounders were common sizes. This does not mean that a 24-pounder is half the size of a 48-pounder throughout, and so on. The actual sizes of these guns are difficult to obtain, but the following table may be of interest : — 12-pounders, bore 4.52in., length 32.36in. 18-pounders, bore 5.16in., length 39.3in. and 28in. 24-pounders, bore 5.68in., length 48.32in. and 36in. The lengths given are for the bores, and it will be observed that two lengths are given for the 18- and 24-pounders, so the modelmaker must acquaint himself with the actual details of the guns fitted to the prototype ship he is reproducing. It must be remembered that in those days engineering had not advanced to such a stage as complete uniformity, and it is very doubt- ful if any two guns were exactly alike in respect of weight and dimensions, judged by modern standards. As previously mentioned, there was a cer- tain amount of definite prejudice against these carronades by some naval officers. For ex- ample, Sir Harry Keppel, when commanding the frigate “‘ Mzander,” writes in his diary, when coming up Channel to pay the ship off after three years’ commission abroad: “ Gave the ship her last coat of paint, and remou nted carronades; neither useful nor ornamental.” They had evidently spent the commission in the hold. The writer is indebted to a retired naval officer for this interesting record. In a model where there are a large numbe r of guns of the same size, and where weight is important, and wood objected to, they can easily be cast in aluminium, or an alloy of that metal, in large numbers from the same mould, provided the pattern and mould are well and carefully made, Make the pattern by turning up from hard- wood, gluing and pinning the excrescences firmly into place afterwards. must be very well This pattern finished and perfectly smooth. There is no need to make allowances for casting contraction, as in very small models it would hardly be noticeable. However, if desired, an allowance may be worke d out and allowed for by the meticulous. The guns would be cast solid, of course, and the castings bored individually by drillin g with a suitable sized drill. This is an easy matter and quickly done, especially if a small jig is made. The mould should be made in the same way as the writer has described in MARINE MODELS a few years ago, during the series of articles on making certain ships’ fittings, but for the convenience of readers this method will be repeated briefly. Take a small cardboard or wooden box and cut down toa depth that will allow the thickness of half the pattern, plus about Sin. Mix enough of Ash’s Dental Plaste r to make the first half mould, getting it smoot h and to the consistency of thick cream. The pattern must be absolutely smooth and greased all over with Vaseline. Fill the box with this creamy plaster and let it thicke n slightly. Then press the wooden pattern firmly down into it until half is submerged in the plaster. Allow to set a little more, and scrape off ali surplus dead flush with top of plaster and smooth off box. Take two little MARINE pieces of round wood and push these into the plaster to form dowels to ensure that the two halves of the mould register accurately each time the mould is put together. Let the first half mould set stone hard, Make sure that the pattern has not stuck. Move the half mould into another cardboard or wooden box of the same size, but twice as deep, replace the pattern after giving the lower half mould a coat of clay-wash (made with an old paint brush dipped in water and rubbed on a lump of common clay), to prevent the two halves of the mould sticking together. The pattern is again greased and the mould box filled up to the top with fresh, creamy plaster, and allowed to set. When dry, the mould can be parted by holding edgewise under a dripping tap, a thin knife being used to facilitate the operation. A hole must be provided in the mould to pour the alloy in by and a second smaller hole provided at the highest point of the mould, or rather of the casting, to serve as a blowhole or vent to let out the air. The mould must be allowed to get absolutely dry before casting is attempted, and the two halves may be bound together tightly with string or wire during the operation. The castings will need very little cleaning up with the file if all is well. They should be painted or chemically treated to obtain the correct colour. These dummy aluminium cannon on no account must be fired: if working models are required then they should be cast in good quality gunmetal or machined from the solid. When machining a quantity of small cannon, a finishing forming tool will materi- ally help to get them all precisely alike and vastly increase speed of production; a sketch of such a tool is hardly practical in these articles as the length of the cutting edge would depend upon the quality and style of the reader’s lathe, but, as previously mentioned, the gun should be roughly turned in the ordinary way and the forming tool used only as a finisher. An accurate profile gauge should be made from sheet steel of the whole or that part of the gun desired, and the forming tool ground away accurately to fit this gauge, which should be preserved for testing the accuracy of the profile of the cutting edge, especially after regrinding and dressing the tool from time to time. Our Magazine deals exclusively with MODELS 317 marine matters, but in the development of armament military and naval purposes run side by side, the one Service learning from the other and vice versa. It is, therefore, difficult not to allude, just a little, to military requirements, and in some instances even to separate the course of development, but it may be said that, since artillery on land claims prior development, sea requirements follow in its steps, the apparatus being adapted to the special needs of ships. Probably it was after the time of the Crimean War that naval armaments definitely took the lead with very rapid strides. It was on land that artillery first became mobile by the use of crude wheels fixed to the rough carriages, whence came the truck carriage for mounting the long guns of the Navy, thus allowing ease of shock to the ship following the discharge by a certain amount of free recoil, the rule followed being, the heavier the gun the less the shock of the recoil. At first, ships’ guns had only two wheels or trucks, placed at the rear of the carriage, but with the larger and more powerful guns, introduced about the middle of the sixteenth century, four trucks, two at the after end and two at the forward end of the carriage, came into general use and remained so for many centuries, The size and diameter of the trucks is of great importance, and artillery used high- wheeled carriages admirably suited for emplacements, but quite unsuitable for sea conditions, owing to the strain and difficulty of controlling the recoil in a seaway. Lack of head-room and deck-space, together with the innovation of gun-ports, tended to reduce their diameter, and for the preservation of the decking, wooden wheels became the order of the day. Again, if the trucks were too high the carriage would not go close to the ship’s side, and the lower the carriage the more easy and controllable was the recoil, so the low carriage, with small diameter trucks, came into general naval use, and was a definite depar- ture from land practice. The heaviest guns were mounted on the lowest deck, just above the waterline, and the smaller in the waist and steerage. Mounted on higher parts of the ship were very small guns, such as the Harquebuss 4 Croe, for cutting the sails and rigging of the enemy by means (Continued at foot of page 318.) ee e 318 MARINE MODELS SPEEDS (IN M.P.H. AND KNOTS) FOR TIME PER 100 YARDS Time in secs.| Miles per hour | Knots 3.5 | 58.44 | 50.75 6 56.82 49.34 Time Miles | 6.0 | 34.09 | a! 29.12 if 55.28 48.01 2 32.99 28.65 53.82 46.75 ee 32.47 28.19 9 52.45 45.55 4 31.96 27.75 1 Time | in secs. 29.60 33.53 8 4.0 | in secs. | per hour | Knots | 10.0) 11.0 | | Miles per hour Knots 2045 | 17.76 18.59 16.15 14.80 12.0 17.05 13.0 15.73 13.66 ~=14.0 14.61 12.69 51.14 44.4] 5 49.89 31.47 43.32 27.33 6 15.0 30.99 13.64 26.92 11.84 16.0 12.78 11.10 10.45 ob 48.70 42.29 ay | 30.53 26.51 3 47.57 17.0 12.03 41.31 8 30.08 26.12 4 46.49 18.0 40.37 11.36 29 9.87 29.64 25.74 19.0 10.77 9.35 20.0 10.23 8.88 3 45.45 39.47 7.0 29.22 6 25.38 44.46 38.62 2 28.41 24.67 oh 43.52 37.80 4 27.64 24.00 8 42.61 31.01 6 26.91 23.37 9 41.74 36.25 8 26.22 40.91 35.53 22.77 8.0 25.57 22.20 5.0 mf 40.11 34.83 a 2 24.94 21.66 oh 39.33 34.16 4 24.35 3 21.15 38.57 5351 6 23.78 20.66 4 37.88 32.89 8 23.24 20.19 5 37.19 32.30 9.0 Leet 6 36.53 19.74 31.72 ay bLidd 7 19.31 35.89 31.16 4 21.76 18.90 8 35.21 30.62 6 ZL 9 18.50 34.67 30.10 8 20.87 18.13 | | NOTE.—-A Nautical Mile=6080 feet (or 1.151 Geographical Miles) Knots=Speed of . . . Nautical Miles per hour SHIP’S ARMAMENTS (Continued from page 317.) of cross-bar shot. These little weapons were mounted with a crude form of universal joint so that they could be trained in any direction, depressed or elevated, with the greatest of ease. It is interesting to note that at this time naval ordnance was really under the control of the military authorities, acting through a Board of Ordnance; under this arrangement the Navy did not apparently receive the attention to its peculiar needs that it might have done, but in due course this matter was corrected. (To be continued.) THE “MARINE MODELS” SPEED TABLE HE above table of speeds in m.p.h. and T knots was compiled at the suggestion and with the assistance of Mr. J. Vines, As the majority of speedboat races are run on a circular course, 100 yards per lap, the usual distances being 300, 500, 600 or 1,000 yards, the table should be useful to Regatta Officials, competitors and spectators alike. The range of lower speeds included will be found useful for ‘* free-running ” boats on the straight 100-yards course. Readers should note that the expression Knots per hour ” is incorrect, and speeds are merely stated as “so many ” knots. MARINE MODELS 319 THE Ge of the commercial blowlamp con- tainers are soft-soldered, and, although this may work all right at low pressures and small heats, | must confess I do not like this practice at all, as if an accident did occur, it might be a nasty one. It is perfectly true that many very reliable plumber’s blowlamps have soft-soldered containers, but this is rather a different proposition, since the lamp is not shut into the confined space of a boat’s hull, but exposed to air. In a petrol blowlamp, also, the heat of the container generates pressure. I should, therefore, only pass a soft-soldered container for model boat work when the container is at the far end of the boat from the burner, as a soft-soldered joint must not be exposed to heat. I have just made up a new blowlamp for my destroyer, and in view of the above remarks I need hardly say that it has a silversoldered container. The body is made from a length of 20-gauge best solid-drawn brass tube, 3in, diameter. When getting this at a metal warehouse, it is important to impress on whoever serves you the purpose this is wanted for, so that the right stuff is supplied, since seamed tube is certain to split under pressure. I can speak feelingly about this, since I was once had this way myself. Fortunately, however, I am in the habit of giving boilers, blowlamp containers, etc., a good stiff test under water pressure before putting them into use. Under this, my pretty little container split neatly along the joint of the tube, and I was obliged to make a new one—a loss of time and material, but thanks to the water- test, not otherwise attended with any serious consequences. The method of making the container is very similar to making a boiler. The ends are of 18-gauge brass, domed and flanged, being beaten to shape over a former, made from an odd piece of tin. mild steel plate. The flanges on the ends are a nice fit for the ends of the tube, and in order to ensure this, I made the ends a shade oversize, and then skimmed them down slightly until they just fitted into the tube. In passing, I might mention what I have found to be the easiest method of making the former for the ends. Rough out a disc by drilling a row of holes that just intersect. To do this needs a little practice, but if there are any tongues left between the holes they can be dealt with through. by sawing or chiselling The diameter of the disc is the same as the internal diameter of the body less twice the thickness of the metal that is being used for To figure this out needs pretty the ends. accurate measurement, and it is possible that the worker has not the means of taking sufficiently accurate measurements, but this can be circumvented by the exercise of a little ingenuity. As we know, the disc has to fit into the end of the tube with just room for a thickness of the end metal all round. If four little slips of the metal are cut and disposed—North, East, South and West—round the tube, the exact fit can be ascertained by practical test as the disc is being turned down, Before passing on, just one little point about drilling the row of holes to rough out the disc. This, by the way, is not intended for the expert, who possibly has access to a drill ing machine, and is used to the job, but for the less expert, who probably has to put his holes through with a hand or breast drill. Make a centre pop and scribe the required circle, and while you are doing this put the centre hole through for the spigot left on the stub end on which the disc is mounted for turning as described 320 MARINE later in this article. These operations are best done on the lathe, and if the disc is turned round during the drilling, it will ensure the hole being put through square. Use the drill pad for this job. Now, as regards the row of holes, a lot of unnecessary labour can be saved, and it will assist the novice to get his holes nicely spaced, if the following procedure is used. Start the first hole with the hand-drill, and go just deep enough for the full diameter of the drill to show up. Then go on to the second one, and do likewise. If the hole tends to run over into number one, or is too far from it, the hole can be drawn over as requisite. Go round the full circle starting each hole in. this fashion. Now put the drill in the lathe chuck, and, using the drill pad, proceed to complete the row of holes. By the way, it is desirable to use a good pad of rag to hold the metal, so that the fingers are not cut on the jagged edges. By the way, the edge of the former should have a very slight taper from front to back, so that the end will come off easily. Also the end can be mounted on the former when we come to skim up for final fit. Next, take a stub end of steel rod, about lin. diameter, put in the lathe and turn down a spigot about jin. on the end. If the hole in the disc to take this has not been drilled, this must now be done, and the disc sweated onto the stub. Mount in the lathe and turn down to the required size, and remember to put a slight radius on the corner between the face and edge, as, if left sharp, this will cut into the brass when you come to beat up the end. By the way, you should mark the stub end when you are turning up the spigot, so that it can be put back the same way into the chuck. During beating, the end must be annealed frequently. If it is found, on examination, that too generous an allowance has been made for the end to be fitted by skimming the flange down, the former can be reduced slightly and the end beaten down to reduce the size. After the final adjustment, the ends should be a nice fit in the tube, so as just to hold themselves in position. When the flux is put on, this fit will be still closer. If the ends have to be forced in, the tube will be distorted when heat is applied. Personally, I rather like to see the ends of the container showing the extent of the radius at the end of the tube, rather than being pushed MODELS in absolutely flush. This is not a vital matter , but, in my “opinion, improves the appear ance. There is one point I should like to make clear. Although I mention skimming up the ends of the container, this must be the merest fraction so as not to lose any amount of metal and weaken the job. Before silver soldering the ends into place, all the fittings have to be made, and everything assembled in position. All surfaces that are to be joined must be thoroughly cleaned up with emery cloth. The fittings for the container comprise a combined filler and pressure pump, release valve and stop valve with a strainer embodi ed. The pump is put through the filler cap, to which its body is silver soldered. To all intents and purposes the pump is standard “Primus” practice, and some “Primus” parts, such as the non-return valve and leather cup washer, are embodied. There are one or two little differences in my pump, made mainly for the purpose of lightening it, but those who do not wish to go to the trouble of making up a pump cannot do better than buy a complete “ Primus” pump, which can be obtained quite cheaply. It will further simplify matters, if desired, to use a separate filler and pump, as both these parts can then be “Primus.” One always seems to refer to this type of pressure stove as a “ Primus,” probably because this firm originated the type, but there are others which will answer the purpose as well. As regards the size of the pump, it is advisable to fit as big as convenient so that pres- sure can be raised quickly. It is preferable to have a pump in which the plunger goes right to the bottom of the barrel, as otherwise only part of the air compressed is passed into the container. The edge of the filler cap can be knurled or fitted with knobs or wings so that it can be screwed in and out by hand without recourse to a spanner. My filler cap is recessed for the rubber washer which makes it gastight. Just a word as to the best material for these washers. I have seen ordinary string, asbestos, fibre, leather and all sorts of materials used, but these either go hard as a rock or are porous. The only satisfactory material is the oilproof rubber used by the “Primus” people. I had long searched for this material, when I was put onto it by Mr, Bernard Humphreys, of the Bournville M.Y. & P.B.C., who sent me a sheet of “ Bulca- MARINE nite” rubber, which I have been using with -great satisfaction ever since. Where they fit, the standard “ Primus” – washers are cheap enough. In this connection it is sometimes found when renewing one of these that the new one seems too big for its job. If it is well warmed, however, it will become nice and flexible, and can be easily pushed into position. The release valve is a rather blunt type of needle valve, and in order to prevent the screw coming out and going adrift, I have pinched up the top of the body. The stop-valve itself, situated on top of the container, is perfectly ordinary in type, being a needle-pointed valve with a V-seating. One little point about the valve itself is that the hole for the pipe to the burner is continued right through the body to take a pressure gauge on the back, if required. The lower end of the stop-valve has an extension to take the fuel pipe conveying the oil from the bottom of the tank, the fuel pipe being threaded to screw into this extension. At the bottom of the fuel pipe is the strainer. The body of the strainer is a shallow cup, open at the bottom, which is, in turn, screwed onto the fuel pipe. Across the open bottom of the cup is a piece of fine brass gauze. One point to mention is that the end of the fuel pipe does not finish flush with the strainer cup, but is extended below and cut off at a steep angle. This leaves a point supporting the centre of the gauze. The reason for cutting the end at a steep angle is to avoid an air space in the strainer above the level of the bottom of the fuel pipe. The size of the filter is only limited by the size of the filter hole as fuel pipe and strainer can be screwed into place after being passed into the body of the container. To do this, screw the strainer onto the fuel pipe and drop through the filler hole. Sufficient light will filter through the hole for the worker to see to fish about inside the container with a piece of stout wire through the bush for the stopvalve. Having insinuated the wire into the hole in the fuel pipe, it can easily be induced to come up through the bush. Having cap- tured this the stop-valve is easily screwed on, and the whole put into place. Before leaving this subject, just a word as to the method of soldering the gauze onto the bottom of the strainer body. Take a MODELS 321 piece of asbestos sheet and lay on it a suitable square of gauze. Put the strainer body on top of this in position, run flux round, and then go round with the soldering iron. After soldering, the spare gauze can be trimmed off neatly with the snips. There are two ways the snips can be used—one with the cutting edge away from the body and one with it against the body—the latter is the right way for this job. Afterwards it can be lightly cleaned round with a file or in the lathe. Still another little point—don’t forget to wash the acid off after soldering before using the snips, as the acid will not improve the snips. One thing for the novice to remember is that though he has a filter on the fuel pipe, there is no excuse for not having a filter on the filling funnel. The fuel should always be strained before being put into the container. The second strainer is a necessary additional precaution. The strainer described can be adapted to bilge pumps, water intakes, etc. Filters in containers can, of course, be cleaned by dismantling, but I prefer to save time and trouble whenever possible, so I clear mine, should it ever be necessary, by means of a syringe, blowing back through the stopvalve. I have two syringes, both of which are used. One is an ordinary rubber pear and, though rubber is not improved by petrol or paraffin, it has stood up well, but I always give it a good flush out with water after use. The other was made from an old short metal cycle tyre pump. I took the end out of this and made up a new one with a suitable adaptor. The spout is made from a mouth blowpipe. I altered the pump so as to get suction as well as pressure by fitting double washers, one looking each way. Now to get back to the blowlamp container. The only other points of note are the clips used. Thete are a number of kinds in general use. One of these consists of spiral springs with a hook on one end passing right over the container. This is very suitable for a speedboat, where there is a tremendous amount of vibration, but is unnecessary in a prototype model. I made clips from cyclist’s trouser bands, which permit the lamp to be whipped out quickly, if required, yet hold it efficiently in place during running. The celluloid-covered bands should not be used, of course, but if the modeller thinks he may scratch his container with plain ones, he can get cloth-covered bands. (To be continued.) ee e 322 MARINE MODELS PETROL ENGINE and HYDROPLANE TOPICS By J. B. INNOCENT (Continued from page 292.) HE pleasant news has just come to hand T that “ Betty’? has again won the “Windermere” Trophy, making three wins in four years. The space occurred when “Oigh Alba” made history by achieving the first run by a petrol-engined boat at over 40 m.p-h. This “all the year” competition is run in conjunction with our contemporary’s annual contest, which contest receives surpris- ingly poor support. Personally, I think the lack of support is due to a number of factors, some connected with the entry formand others with the trouble of recording runs with all details, which may never be required. There have also been two rather unfortunate incidents, which resulted in first ‘* Betty” and then * Little Star” being disqualified, though Betty’s ” run was allowed to stand for the “Windermere” Trophy, but not the Model Engineer competition. In both these cases the full course was not covered, owing to the line being a trifle short—in neither case did the error amount to half of one per cent. Owing to these disqualifications and the considerable detail required on the entry forms, I believe the average powerboat man considers there is more than enough red tape about, and nothing is more disliked by the powerboat fraternity. I have spent time at a number of different games, but I have never come across quite such a marked dislike for officialdom as is to be found in the power-boating world. The extent to which it has got hold of us is, | think, unfortunate, for whilst it is very pleasant to be free and easy, it makes things needlessly difficult for our regatta organisers and officials. Furthermore, it is not helping the running of very fast boats, for other competitors will take advantage of their waders to spectate from the water instead of the bank. This both inconveniences and worries the man handling the boat and also roughens the water unnecessarily. During last year the possession of a camera was freely used as an excuse for staying in the water, so I should like to point out to these picture seekers that their obtaining a photograph might easily cost somebody else months of work in repairing an engine. For my own part I should like to see our events run to a much stricter schedule than is usual, for then the competitors would have the reliability and startability of their motors constantly before their minds, and this should eventually eliminate the slowness of proceedings which is all too common. The time saved could easily be used, for then “ one run only ” need no longer be enforced, or another event could be brought in. The last item of racing engine machining | wrote of was the piston, which naturally leads me to the barrel it runs in. I have already given my ideas on cylinder design, and, really, there is nothing out of the ordinary in the finishing of a racing cylinder. Whether you utilise a casting, or cut it from the solid bar, does not matter, for it is a perfectly straightforward job. There are four points which must be borne well in mind when any barrel is made, and they are: the parallelism of the bore, the truth of the bolting flange with the bore, the adequacy of the cooling arrangements, and the means of holding things to- gether. In connection with the last of these, I have introduced what is to me a new method of holding down the barrel and head in the motor on which I am now working. It con- sists of fitting studs to the crankcase, which secure the barrel by the flange in the usual way, but the nuts are very long so that through bolts can be screwed into them. These through bolts hold the head down by brass nuts, which nuts also support the rocker gear. The brass nuts are deliberately made the weakest link in the chain so that damage resulting from trying to compress water will be minimised, You may remember that “Betty” once took rather a sudden gulp, which resulted in the barrel breaking off at the flange, so that we were minus quite a few bits and pieces at a most inconvenient time. The machining of heads is certainly a problem when the valves are angled and the parts curved. I have often wondered why Betty’s ” head has behaved so well, for it was nearly the first piece of machining | ever did, and certainly I would not dare to set anything up now in the way I held that head. To make matters as easy as possible for machining, I see that all my fins are of even height on the pattern, and the first thing I do is to set up the casting in the four-jaw MARINE and take a cut over them. Then the valve line is marked out and transferred to the underside, and I am ready to start work. With the casting once more in the four-jaw, but with the flat top of the fins against the chuck face, the job is set up to the scribed lines, faced off, recessed for the spigot and turned out to a template for the combustion space. For this contour turning I finish with a tool made from an old flat file, which is ground to be almost a form tool. This might not work too well in cast-iron or bronze, but is quite sound when it is a light alloy that has to be cut. With the inside of the head to shape, the valve line is again scribed in. This is easiest with the job still in the chuck, if you can use your scribing block on the lathe bed. Remove the casting from the chuck and make the valve centres on the scribed line. These centres should be dotted with a sharp punch. Now drill the holes for the holding-down bolts: the position of these is best marked out before the casting is removed from the chuck. The problem now to be solved is how to set up the head at the correct angle, with one valve centre running true, and the solution is to make a wooden block, preferably hard, to go between the casting and the face plate. This block must have its two chief faces at an angle to each other equal to half the angle between the valves. Fit bolts to the block to suit the holes for the holding-down bolts in the head and provide a means of clamping the block to the face plate. Having set the casting up somewhere near, you require a gadget known asa centre wobbler. This consists of a rod pointed at both ends, which is a tight fit in a ball mounted near one end: the ball is held in a clamp which leaves it free to wobble. The point at the short end of the rod is put into the centre dot you wish to set up, whilst the shank of the wobbler is held in the tool post. You will see that if the centre dot is not true and the lathe is pulled round slowly it is easy to observe the error by the.increased wobble at the point of the long end of the rod, but, of course, the wobble here is in the opposite direction. I made my own wobbler in about half an hour, using the ball from an old crystal detector, and it is certainly one of the most useful tools I have made. With the first centre true drill through for the valve guide hole and finish to size by boring to ensure acuracy, then bore out as MODELS 323 much of the port as you can at this juncture and cut the recess for the valve seat if you are using lined seatings. Should the head not be in light alloy, and you are not fitting separate guides, then you should proceed a little differently, for it is not possible to use a boring tool in the hole in which the valve will run. First you should start a drill truly and cut out the port as far as possible. This should have eliminated the first short hole and the centre drill must again be used to start another. Then run an undersize drill right through and follow this with a D bit to size the hole. Lest you wonder why I recommend two starts, | would point out that bronze is the worst of all metals for making drills wander, and iron can also be very troublesome, so the shorter the holes the better. The second valve centre is now set up and the same procedure is followed. Special care should of course be taken with the finish of any valve seat cut-outs, as the head would be ruined if a seating came out whilst running. With a racing head, where there is so little room, | prefer to cut the plug hole from the inside and mount the head in the same wa as for machining the ports. To finish the plug seating the head is screwed onto a mandrel, and it is likewise spigoted to form the seats for the valve spring collars. Now the head is set up on an angle plate and faced for the exhaust pipe seat, and the port is bored out as much as possible. This forming of ports is a very fiddling job, and particularly so when they have any appreciable curve. To blend the two holes together and generally shape the port, I use a flexible shaft and large dental drills, finishing with a ball-shaped grinding stone. I have not so far obtained a polished finish with the solid stone, and reckon to finish off with a little leather buff and emery powder and oil. (To be continued.) eee 324 MARINE SAIL MODELS TYPES By G. W. Munro (Continued from page 296.) [° considering the two-masted vessels we have a large variety to deal with, as these are probably the most numerous and varied in every way. It is not size of vessel which helps one to determine the number of masts, so much as the work of the boat, number of crew, and locality in which she is to sail, which predetermines her rig. Personal opinion will also play a very large part in the rig of a vessel, especially a small one. The smallest classes to be rigged with two or more masts are the Luggers. These boats vary in size very much, but we do not see them so large now as in Nelson’s day. Some of these Luggers were as large as a twomasted Schooner. The position of the masts should help one to guess at the rig of vessel when only the hull is available in the form of a model or the Lines and Deck Plan. The space from the stem to the foremast, from the foremast to the mainmast, and from the mainmast to the after-end of the boat, should be very nearly equal for a Lugger. We might also say that this vessel is rigged very like a Fore-and-Aft Schooner, except for the head and luff of the sails attached to the masts. The method of rigging a Lug was mentioned last month, and, if we apply this method to the two or more masts, and treat the rest in exactly the same way as a Schooner, we have a general idea of the Lugger. We have two more two-masted vessels very like the Fore-and-Aft Schooner in rig. These are the Yawl and the Ketch. The Ketch has a main and a mizen, and, like the Lugger, these two masts should divide the length of the deck fairly evenly, but not essentially so. Some authorities have given it that a Ketch must have a mizen area more than 50 per cent. that of the main, while a Yawl has less than 50 per cent. for its jigger area. The general definition is that a Ketch has its mizen stepped forward of the stern, and a Yawl its jigger abaft the stern. Here, again, you will notice that they call the one a jigger and the other a mizen. Contrary to the usual practice of naming a sail from the mast to which it is attached, the procedure has, in this case, been reversed, and the sail has given a name to the mast. Although we have two versions for determining the rig of these two vessels, it will be found that they seldom or never conflict, and together form a useful rule for the early sketches of a sail plan. Sailing out of the Thames we have the Barges, and, as everyone knows, they have a large sprit to extend the mainsail. The bargees call the small after-sail a mizen in contradistinction to what was said above about the Yawl and the Ketch. Some of the larger Barges have their mizens rigged with a gaff. They are then called Mules. Other Barges have a gaff on both masts, and these are called Ketchy Barges. The majority of the Barges have one head —a-sai foresail — but l when there is a jib it is run out on the bowsprit. These Barges are called Spriggies on this account. I do not know if my spelling of the names of the various types of Barges is cotrect, as I have gathered this information merely from odd chats with the bargees from time to time. It is not quite correct to say that a Barge has one head-sail, as very frequently they set a sail between the stem and the topmast head. This sail, unlike the main, mizen and topsail, is of white cloth, and not painted red. I have had various names for this sail, but I should call it a jib topsail. From time to time I have listened to model enthusiasts discussing and criticising models of Barges, and most of them seem to have a rule about which sails should be coloured, and which left in plain white. From the window of my little den here I can very often see as many as 40 to 45 Barges sailing up on the wind and tide. On each of these occasions I see several variations to these hard and fast rules I overhear. However, I am sure if | made a very fine model of a Barge and coloured all the sails red except the main, the judges at an exhibition would knock off quite a number of marks for that reason, yet I have seen several Barges with plain white mainsails, the mizen and the foresail red, and the other head-sails white. Nevertheless, it is usual to see a Barge with her fore, main and mizen and main topsail all red. These are the heavy MARINE working sails, any two of which will be set in the worst weather. All other sails are meant for very fair weather and are only set occasionally. While on the Barges it should be mentioned that there are some rules which are never broken in the rigging. The sprits, including the bowsprit, are always set up on the starboard side of the Barge. It is interesting to note how these vessels got their names in the far-off past. As one might imagine, the name Barge is derived from old French, and is a variation of Barca, a Barque. Probably our nearest modern equivalent is Cargo Boat. The word Yawl is from Swedish, and means a Jolly Boat. These Jolly Boats were part of the stock-in-trade of every sea-story writer of a few years ago. No captain could possibly give an order in connection with boat work without mention- ing the Jolly Boat. The name Ketch is merely a mispronunciation of Catch. Originally these little vessels were armed with a couple of mortars. In appearance they seem to have had a lot of Dutch influence. On the mainmast, which is stepped rather far aft for a two-master, they carried yards as on a full-rigged ship. The mizen had a gaff and a topsail set between a cross-jack and a mizen topsail yard. In appearance they look rather like the old- fashioned Barque, but with the foremast removed. These vessels were square-rigged, just as much as a Ship, but to-day we know them as fore-and-aft entirely. Perhaps the most popular of all craft is the Schooner. She is often said to be the most dainty, most handy, and a lot of other complimentary names. However, she represents one of the cardinal points in our rigging types. She was developed from other types, and other types have been set on their careers from her, Originally, I believe, a Schooner had the usual two masts with gaffs extending foreand-aft sails, yards spreading topsails as in a brig. One may see one of these Schooners in the engravings in Falconer’s “ The Old Wooden Walls” of 1769. Contrary to this, Sir Alan Moore, in his “Sailing Ships of War,” 1800-60, shows a very similar vessel as a Brig. It must be mentioned that the latter vessel has. top-gallant sails as well as topsails. Personally, I should call this vessel an Hermaphrodite Brig—half Schooner and_ half Brig. MODELS 325 A Brigantine, on the other hand, is a vessel with square rig all down the foremast, and fore-and-aft on the mainmast. We are accustomed to seeing Schooners with two or more square sails on the fore topmast. These are known as Topsail Schooners, and it is quite possible that the topsails are a survival of the original. Those on the main having disappeared through a possible fault in the placing of the centre of effort. , (To be continued.) THE MODEL YACHTING FLEET HROUGH the courtesy Mr. W. H. Bauer, r Registrar of the M.Y.A.,of we are able to give readers the number of yachts of each class now appearing in the Association’s Register : — New Registrations during 1936, _ 98 10-rater A-class 6-metres 36in. re. mm 32 67 Le 22. al |2-metres 30in. Total No. registered. 761 422 351 77 237 — 9 218 296 1998 From these figures it will be seen that in the United Kingdom the 10-rater retains its pride of place as our most popular class, the number of new boats registered during 1936 and the number on the Register being almost exactly equal to the total of the A-class and 6-m. put together. The figures for the A-class, 6m. and 12-m. include the Scottish registrations. It will be noticed that though the 6-m. only total about five-sixths as many as the A-class, the total of new constructions is twice as many. This is probably accounted for by the recent changes in the I.Y.R.U. rule. The 12-m. appears to be dying out, and the 30in. has made no progress at all. There are an immense number of the 30in. boats about, but as a club class, the feeling seems to be that the boats are too small for competition work. The 36in. is rapidly coming into favour, owing to its portability and suitability for small waters, and shows the second largest number of new constructions. The Marblehead class is not recognised as yet by the M.Y.A., but from all accounts there must now be the best part of a hundred boats to it afloat in the United Kingdom. “A * CLASS. Championship. finalists 1936. Also “Comet,” Cup Winner. Similar design as Duralumin mast, 4 Finalist 1934, British ‘‘ Quest” and “ Iris,” suits, spinnakers. £15. 10-RATER. ‘ Nancy,’’ Cup Winner, varnished yellow pine planking, 12 months old, “ Gloria” design. 3 suits, spinnakers. Both excellent condition. £12. Jones, 11, Haldane Avenue, Birkenhead. rn 326 MARINE MODELS THE CURVED MAST IN THEORY AND PRACTICE By A. C. Davison, A.M.I.C.E. (Retd.) os AVING just finished my second spell of about 12 months with a curved mast, I have arrived at some sort of definite opinion about it. I had better warn strangers, however, in advance, that the value of the said opinion among our young friends at Kensington is something below absolute zero. The person who made the first modern curved mast probably had chiefly in view the idea of getting a larger area of sail exposed to the wind when beating at a close angle to it, by preventing the top part from twisting off it. This it does without any serious disadvantage, but at the ex- pense of a bad mechanical hash when the boom is let far out. To work sweetly, any fore-and-aft – sail should be able to turn freely as a whole, like a door on its hinges, Fig. 1. sketch shows but a sail on a curved mast that it cannot. must turn The on a vertical hinge formed by a line from the masthead to goose-neck. To see this, imagine the sail to be frozen stiff like a board: the part A would then have to remain always pointing fore and aft, and the rest of the sail could not turn unless a flexible part or hinge was provided along the dotted line. Even if this be provided the sail cannot turn if the boom be held down by a rigid kicking strap. To turn and follow the foot of the sail, which is turning round a raking line, the outer end of the boom would have to rise, but the boom, being generally hinged to the mast and held to it by the kicking strap, can only swing round in a horizontal arc. The result in practice is that it only swings at all from the flexibility and elasticity of the sail-cloth and “give” of the various parts, and the fight between the boom trying to rise with the sail, and being held down by the kicking strap, results in a heavy forward thrust being put on the boom, which jams the joint at the gooseneck. This I found the most trouble in practice; unless the kicking strap was left so slack as to be of little use, the boom was inclined to stick on one side. Another drawback is that owing to the indefinite sort of form that the sail has to assume, the part A goes baggy and rests on the shroud sooner, and the boom has to be sheeted closer in to ensure working the helm. In spite of these drawbacks, however, the sail seemed to pull quite well, and my feeling is that notwithstanding theoretical imperfection the arrangement has, taken all round, rather more efficiency than the ordinary straight mast. Mr. Cobayashi’s swivelling top-mast, which allows the sail to turn properly, is decidedly better, but he missed making the best of it by only providing two positions for fixing it in. It would have been better with some arrangement for locking it at intermediate points. A minor trouble that this does not get over is that it is more difficult to make sails to fit nicely to a curved mast, and from this and other considerations I am going back to the plan that I have used for a long time with fair satisfaction. This is a high-peaked gaff with Bisa: a short rigid stay projecting back from the top-mast, to which the gaff has an additional sheet, so that the swing can be checked at any angle, from amidships to right out, as desired. This does all, and more, than the curved luff sail does in a more simple manner, and I would recommend a trial of it to anyone wanting a little more power “on the wind ”’ and not quite hidebound by tradition. MARINE MODELS 327 se s me nm felis N~ ” Ku) m= aeakten ~ £i\ ee A ar + —s 126 htek OS 4.” Se —— gar DO —— i» shes ——a [In order to enable us to make the best use of the space at our disposal, Club Secretaries ave requested to make their reports brief and to BRADFORD M.Y.C. It was decided at the meeting held at the ‘* Stone Trough “’ on January 3, that the race for the **Bray- shaw ’’ Cup, 36in. Restricted, be resailed on Sunday, February 14, at 11 a.m. In addition to the *“* Open ’’ races at Easter and on May 16 (see large advertisement in this issue), the following principal fixtures were arranged : — First Weekly Flag Race—Sunday, April 4. 10-rater ‘* Hirst ’’ Cup—Sunday, May 2. ““ Coronation *’ Race—Wednesday, May 12. ‘* Open ”’ 36in. Restricted—Sunday, May 16. Northern M.Y.A. 10-rater—Saturday, June 5. 6-m. ‘Vernon Dawson’’ Cup—Saturday, June 12. 4 All Classes ** Sidney Carter ‘’ Cup—Sunday, June 0. A-class ** Atkinson ‘’ Trophy—Sunday, Oct. 3. 10-rater ‘* Mirfield *” Cup—Sunday, Oct. 17. ** Temple ’’ Cup—Saturday, Oct. 23. Tie Restricted ** Brayshaw ‘’ Cup—Sunday, Oct. 31. The Saturday races commence at 3 p.m., and the Sunday ** Cup ”’ races at 11 a.m. Visitors are welcome, and refreshments can usually be obtained at the Club Canteen. J. P. CLAPHAM. HASTINGS AND ST. LEONARDS M.Y.C. The Annual General Meeting was held at the Metropole Assembly Rooms, Hastings, on January 7, Rear-Admiral H. E. Dannreuther, D.S.O., presiding. The Hon. Sec. spoke of a most satisfactory year’s activities, and said that membership had increased by over 50 during 1936, whilst six Cups had been presented for competition by local donors. The Hastings. M.Y.C. had held a highly successful Exhibition of Models last September, and had contributed over £60 to local charities during the year. The club now catered for the 36in. Restricted class, the 50-800 Marblehead class, the 10-raters, and a handicap class for juveniles, in addition to powerboats. It was decided to reaffiliate to the M.Y.A. and to affiliate to the M.P.B.A., and to augment the powerboat section by forming a model engineering and aircraft section. It was also decided to invite a series of matches with other clubs. (Hon. Secretaries, please note!) The election of officers resulted as follows: — President, Rear-Admiral H. E. Dannreuther; VicePresidents, Commander Bray, Dr. E. Carmody, Mr. W. H. Dyer, and Mr. J. Norman Grey; Hon. Sec’, Mr. W. J. Balcombe, 57, St. Mary’s Road, Hastings; Official Measurer and Racing Secretary, Mr. D. Cheal, 39, Quarry Road, Hastings; Power Section Secretary, Mr. T. Bridgland, 31, St. George’s Road, the point.—Epitor, MARINE MODELS. ] Hastings; Commodore, Mr. S. G. Adie. Mr. W. H. Dyer is Secretary of the Hastings Publicity Association, whilst Mr. J. Norman Grey is Entertainments Manager to the Hastings Corporation. The Racing Secretary suggests that there is scope for the formation of a Southern Counties League to arrange for holiday facilities for visiting sportsmen, and invites Secretaries of Affiliated Clubs and of London League Clubs to drop him a line. The racing season of the Hastings M.Y.C. reopens in March, whilst the Second Annual Exhibition will be held from Saturday, August 28, to Monday, September 6, both dates inclusive. HUDDERSFIELD S.M.E. 36in, Restricted Class.—The concluding race for the 1936 series was held on Sunday, January 3 (postponed from December 13, owing to ice). This race was again won by ** Elma,’’ but “‘ June ’’ (Mr. H. Procter) again retained the Championship by a narrow margin of | per cent., with an aggregate of 83.8 per cent. ‘‘ Elma ’’ (Mr. H. Honeybell) was second with 82.8 per cent., and ‘‘ White Nymph ” (Mr. J. Tolson) third with 80 per cent. The Society’s fleet now numbers 12, excluding a few new boats building, as well as a number of the Marblehead class. Racing will recommence at 2 p.m. on Sunday, January 31, and every fortnight following, excluding holidays. ” RoC: Hs RYDE M.Y.C. (ISLE OF WIGHT) (British Headquarters of the Marblehead Class) According to the time-honoured custom, the club held a race meeting on Boxing Day morning, and some enjoyable hours were spent, and good sailing resulted. The Handicap and 36in. Restricted classes competed for a Marblehead model, presented by A. Feltham, Esq., the designer and builder. The winner of the model being D. Wyles, Esq., and the second prize going to Miss Mary Ward Pearson. In the Marblehead class race the finishes were, as usual, very close, Lt.-Comdr. T. Jackson being the winner, and G. L. Matthews, Esq., second. The Racing Committee provided the prizes. On the following morning the Marblehead class competed for a medal presented by the Vice-Commodore (Councillor A. J. Williams), and Lt.-Comdr. Jackson was again successful, after sailing off a tie. Judging by the attendance of the townspeople and _ visitors, even at this time of the year, the sport is growing in popularity. A. K. 328 MARINE SCARBOROUGH M.Y.C. The club had a very successful season in 1936. This club sails all the year round, and a notable feature was the large number of new boats launched. Indeed the fleet has been changed almost beyond recognition. ** Ivy ’’ (Mr. Vitty). /was taken out of commission, and a new “ Ivy II ’’ was brought out from the same lines, and scored four wins in her first five races. Another new-comer was from the Captain’s yacht, ** Osprey,’’ silver and blue, a very fine-lined boat of thoroughbred appearance, from lines by Mr. Reg. Lance. She showed remarkable speed, especially in light winds, and annexed the ** Garfield *’ Cup. In the smaller sizes we have a Marblehead by Mr. Larcom, and a brilliant little 36in. Sharpie by Mr. Vitty, from a design from the board of Mr. A. E. Smith. The latter, on her first appearance, came within an ace of capturing the ** Smith ’’ Cup for a mixed class, only Just failing to carry the day against the frigate‘* Hector,’’ carrying six times her sail area, and racing on a course that was chosen for square-riggers. Races away were held at Darlington and Hull. For the first time we managed to put it across the latter, and thus proved that, in spite of experience to the contrary, we could do that there ’ere. Windjammer Championship, 1936.—Five vessels competed for the Championship in 1936. The winner was Mr. P. Larcom’s full-rigger ‘‘Miramare’’ (L.W.L., 66in.), which defeated last year’s cham- pion, Mr. D. J. Boyle’s ship, MODELS Model Yachting Association The 1937 M.Y.A. Fixture List will soon be in the printer’s hands. It will contain, in addition to the list of the season’s fixtures, a list of the Affiliated Clubs and Individual Members. In order to have this list complete and to avoid any omission will those concerned kindly send to the Hon. Secretary any changes of sailing waters or addresses, while their remittances for Affiliation Fees should be sent to the Hon. Treasurer at their earliest convenience. Cheques and P.O’s, should be crossed Barclays Bank, and should beanade payable to “The Model Yachting Association.” A full report of the Annual General Meeting will appear in the ** Marine Models.” Some desperately hard struggles took place. The ‘* Cicely Fairfax’’ was generally the faster ship to windward; the others were often the faster downwind, and the 1936 Racing Rules put a premium on accuracy, the steadiness of the ships of the Larcom Line making them very difficult to beat. Their speed off the wind, quick-tacking, and steadiness on the course put the Larcom flag on top for 1936. System of racing: tacking where necessary. Scoring: 5 points for a win, either way, with 3 points given to the second ship if she makes port at the first landfall. Fought out in duels. Results (winner is the one first to take three matches):—** Cicely Fairfax ’’ beat the** Hector ”’ twice. Ist Rubber—48 to 56; 80 to 23; 70 to 31; 65 to 41. 2nd Rubber: 55 to 30; 45 to 25; 55 to 30. ‘** Cicely Fairfax ’’ beat ‘* Alva’’: 45 to 25; 35 ” number Acting Hon. Secretary, 248, Burrage Road, Plumstead, S.E.18 Bradford Model Yacht Club LARKFIELD TARN, RAWDON, nr. LEEDS EASTER OPEN RACES, 1937 The following Races, under M.Y.A. Rules, have been arranged. Entries 2/6 each, will be received up to 10 a.m. each day. Friday, March 26th— Team Race, 4 classes—Prizes Saturday, March 27th— A’? Class, “ Bradford ’’ Cup—2 Prizes Sunday, March 28th— 10-rater, “Claro ’’ Cup—2 Prizes to 25; 25 to 0. Monday, March 29th— monde Castle.”’ Starting time—I] a.m. each day. ‘** Cicely Fairfax ‘’ and *‘ Miramare ’’ beat ** Or- ‘* Miramare ”’ beat ‘‘ Cicely Fairfax ’’ twice. Ist Rubber: 51 to 65; 50 to 10; 50 to 30; 63 to 53. 2nd Rubber: 41 to 65; 28 to 65; 68 to 35; 38 to 30; 38 to 35. This gave the 1937 Championship to the full- rigger *‘ Miramare.”’ of Mr. W. J. E. Pike, *‘ Cicely | Fairfax ”’ (L.W.L., 553in.). The big frigate, ‘* Hector ”’ (L.W.L., 59in.), which has lately shown extraordinarily fine, fast and accurate sailing, also competed; and Mr. R. Smith’s Blackwaller, ‘‘ Ormonde Castle “’ (L.W.L., 55in.). The fleet was completed by the Barquentine, ‘* Alva,’’ of similar dimensions. March 6-metre, “ Wade ’’ Cup—2 Prizes The Club Canteen will be open daily for the supply of Tea and Refreshments. A Landing Stage having been constructed, the yachts can now be handled without the use of waders. (Owners of 36in. res. Yachts are informed that an ‘‘Open’’ Event is to be held on Sunday, May 16th.”) MARINE OQ” Scottish Page for last month brings us the accusation that it is ‘‘ almost stalemate,”’ and that we ‘‘are evidently waiting for something to turn up.’ Frankly, there is a considerable amount of justification for this assertion. At this period a dearth of interesting matter is invariably experienced, and, like all journalist ic enterprise, fundamentally we are dependent on at least some news coming in to form: a basis for comment, wise or otherwise. Of course, we could, per- haps, take a hearty supper of Welsh rarebit and pickles and transcribe the resultant internal, or infernal, visions supervening, but, of course, this has already been done, more or less realistically, by other writers of greater renown, and we are nothing if not original. Or ain’t we? (In case of causing undue perturbment the slang is intentional.) And the object of all this fulmination? Well, if the various Club Secretaries cannot answer this ques- tion for themselves we ‘* mun juist let it bide,’’ as we say in the alleged vernacular—whiles. And no prizes are offered for correct, or incorrect, solutions. Too near ne’er day, see! Curiously enough, we have been inundated with anxious inquiries as to the transport facilities to America—at the earliest possible moment—since the last issue of this Magazine, and not all from bachelors, either. Mysterious, very. Wha says we hae na Model Yachting news? We have to congratulate the Glasgow Society of Model Engineers and the Clyde Society of Shiplovers on a most creditable exhibition staged by them by courtesy and on the premises of Messrs. Lewis’s Palytechnic Stores, Ltd., Glasgow. Un- fortunately, we were extremely busy at the time, and only able to afford a more or less cursory visit, much to our regret, as it was obviously well worthy of a detailed and careful examination. In our hasty run round, however, we noticed ‘‘ Oigh Alba,” bearing the scars of some of her misfortunes, modestly hiding in a rather inconspicuous position, and sans any intimation of her notable performances. To our mind this was a blemish on an otherwise excellently arranged display. If a card had been attached, giving the information that this power model had held the world record by running at over 42 miles per hour, with the date and other particulars, we are sure it would have attracted immense interest from our mechanically minded Glasgow public. Perhaps the omission may have been rectified subsequent to our visit, as the Exhibition ran for several days thereafter. It would be invidious to refer specially to any selected items from such a galaxy of expert craftsmanship in so many varied forms, and to maintain our well-established reputation for veracity, we admit we had insufficient time to justify detailed criticism. It is sufficient to record that the entire collection reflected infinite credit upon the Societies, and the individual constructors represented. We are glad MODELS 329 to add that public interest in the exhibits was intense. We again congratulate the participants on an outstanding achievement. While not concerned with racing sailing craft, the display included the 6-m. ** Violet “’ and ‘* Charmée,’’ winner and runner-up respectively in the ‘‘ Lewis *’ Cup race, and another 6-m. example, *‘ Stella ’’ (D. Weir, of the Dennistoun Club), was also on view. We understand that Saltcoats has produced several new models during the recess, which are expected to give a good account of themselves when active racing is resumed. Commodore Robertson has a 6-m. Rodrick design, and this model has been the subject of favourable comment, equally for craftsmanship as for design. Another A-class, from the board of Mr. W. Smith, Largs, has been built by H. Miller, and is likely to prove a welcome addition to the existing Saltcoats fleet of this class. Mr. McCallum also has a new “ six” from the ‘‘ Glenesk ’’ lines, and, if she is anything like her progenitor, we anticipate she will give some of the former leaders something to think about ere long. W. Gilfillan has another new “‘ six ’’ on the stocks to add to the tally. At the West of Scotland, Mr. W. Brock is building a 6-m. to his own design. Another is under construction by W. Wallace from a design by Sam. O. Berge. This club appears to be taking up the A-class seriously. At any rate, Mr. G. W. Munro has one on the stocks from the board of Mr. P. J. McGregor; the new Rodrick boat is showing improved form, and we understand Mr. H. Morris is busy with the erection of another from the design of Mr. W. Smith. Altogether, we will be interested in comparing the performances of these craft when the days lengthen. We are informed that Mr. W. Smith, of Largs, has been appointed Official Measurer of the Y.R.A. for the Clyde area, and hasten to extend felicitations to this enthusiastic model yachtsman and good sport on the distinction conferred upon him. Port Bannatyne has sustained a great loss by the passing to rest recently of Mr. Charlie Gow, who was a consistent builder and active sailer of models for many years. We tender our sincere sympathy to all his colleagues and friends. Morning glory fades, Noon draws into night, But through the darksome shades, We reach a purer light. We have just returned from a brief period of rest in the Kyles of Bute. And you may believe it was a rest without any doubt. We were in bed early, in the evening, not morning, and rose late, in the morning, not evening, and did we enjoy the peace and quietness! Despite unfavourable, unsettled weather, and notwithstanding our long and intimate acquaintance with this glorious district, the scene was ever changing and always new. Now it was a perfect rainbow, or perhaps two at the C n 330 MARINE same time, and again the distant glint of fitful sunshine on the hills veiled with a thin, shimmer – MODELS PARTICULARS WANTED ing curtain of diaphanous mist, faintly luminous in O*: of our readers, Eng.-Captain M. C. John- porting themselves in the water, and the sea-birds anxious to secure the lines and particul ars of the replica of the Gogstad Viking Ship, which a purple sheen. Anon, a school of grey seals dis- beating up against the strong, gusty breeze. And, over all, the noisy silence of isolation and seclusion and peace. Noisy silence? Yes, because the crescendo hum of the wind, wash of wave on shore, call of pees-weep and gull, all blend and provide a balanced natural cadence, free from the clangour of our every-day town life, merging into the atmosphere, as it were, and only dimly perceptible to our conscious senses. In summer, with the white sails of constantly flitting yachts, the ebb and flow of holiday makers, mild zephyrs and sunny days, there may be more “ life,’’ as gregarious mankind generally understands it, but for our part we some- times prefer the quiet of the winter, and certainly derive benefit from it. And what has this to do with model yachting? Why, nothing, but is it not true? And does it help us to fill the ‘* Page ’’ this month, Mr. Editor? THE SCOTTISH COMMODORE. THE 6-METRES Owned son, 129, Garrison Lane, Felixstowe, is was built in 1880 at Bergen, and sailed across the Atlantic on her own bottom. She proved a marvellous seaboat and created a great sensatio n on her arrival in America. Captain Johnson is anxious to make a model of her, and will be grateful if any reader can oblige with lines and particulars. Any reader who can help our correspondent is requested to communi cate with him direct at the above address. The Editor will be pleased to receive articles for publication, either technical or constructive. Articles submitted will be carefully considered and, if unsuitable for MARINE Mops s, will be returned if accompanied by a stamped addressed envelope. Every care will be taken, but no responsi bility can be accepted for loss or damage. MODEL “CLUTHA ” by John A. Stewart, West of Scotland M.Y.C. ‘*Clutha ’’ is an adaptation of a typical design by Eng.-Rear-Admiral Alfred Turner, 1932. The owner considered that for sailing on a tree-girt inland pond where reaching winds prevail, the fin might be lengthened two or three inches with advantage for the purpose intended. The late Mr. John A. MacCallum, naval architect, Glasgow, made the desired alterations. The season of 1933 was spent in- experimenting, not very successfully, with cocked-up booms and other contrivances. In 1934 “ Clutha ‘’ settled down to racing, winning the “Robertson’’ Cup in that year, the National Championship in 1935, and the Scottish Championship in 1936. The ** McAndrew “’ Cup was won in 1934 and 1936, and numerous other prizes, mainly on her home waters, for the owner has not time to take ** Clutha ’’ about to open regattas. ‘‘ Clutha ’’ has proved to be a good, all-round-boat, being specially to windward in light airs or a good sailing good breeze. The hull was built by Mr. J. McKinnon, the hollow mast by Daniels, fittings by Bauer, and sails by Drown. BOOKSELLING DEPARTMENT Readers books quire. books, are reminded (technical that or otherwise) we can that supply they may any re- We do not carry an extensive stock of but can mention title, obtain to order. author’s name, Orders should and publisher. By placing orders with us, readers are directly helping MaRINE MODELS. Enquiries are dealt with promptly and, whenever possible, answered by return of post, Photo: “ CLUTHA,”’ 6-METRES, W.S.M.Y.C. Elia Stem MARINE MODELS 331 AMERICAN NEWS By C. O. BROOK (Hon. Secretary, Eastern Division of M.Y.R.A.A.) J spent a clean nearly the ** different ’’ week-end—started to dust completed from three the shelves—saw volumes of my MARINE MopELs—thought I’d glance into one of them— became so absorbed, I started with the first 1934 issue (April)—the shelves have not been dusted yet —they make interesting perusing these cold winter nights. We hardly realise what a wealth of information and fine photographs they contain. Try it, Skipper ! Several of my correspondents ask what the status of the new I.M.Y.R.U. is in relation to the several National Associations—such as: ‘‘ Has the new International Association been recognised as the * Boss ’ outfit of Model Yachting>?’’-—we would like to know. Just received a ‘* Resolution ’’ on Spinnake rs, signed by the I.M.Y.R.U. Secretary—I do wonder why they will make me sweat—I have a great big ” spinnaker—some 2,800in. of cloth—it is a wonderful driver (until it sags in the water; and do | say nice things then?). I am much in favour of leaving a good set of rules alone, especially after | spend $5 and then find I have to discard the purchase. We would like to learn the reason for the restrictio ns on spinnakers. I would like to see them abolish the fore-triangle measurement—why> Oh, I guess my new “‘tub”’ sails better when I set the jib ahead a couple of inches. Charlies Farley (Sec., M.Y.R.A.A.) is like a hen on a hot griddle over the dates, venues, etc., for 1937, Why, oh why are Secretaries and clubs so slow in responding? Some clubs haven’t given us the dates for events they were asked for a year ago —and the event is over now. national competition; or, would the average repre- sentative have to re-cut his $10 suit—not through lack of care on his part, but through lack of under- standing on how close measurements must be. Help through these pages at this time will be most timely, since there seems to be a healthy interest in the A-class model—perhaps a book is sold that covers these subjects minutely with a minimum of technical phrases. There is a dearth of news for the rest of this winter period, but I look to see it break out with a bang pretty soon; and that’s that till later. [We commend to our correspondent’s notice the chapter on Measurement in Model Sailing Craft, also the article on the Toronto S.M.E. Measuri ng Apparatus, which appears earlier in this issue of MARINE MopELs.—Eprror, M.M.] AMERICAN FLOODS E tender our heartfelt sympathy to all our W American readers on the frightful calamity which has overtaken the districts of the Ohio and Mississippi rivers. All Britons will join us in this expression of condolence to our cousins in the States for the disaster that has overtaken them. CANADIAN NOTES I’m in your corner, Charles—wish I could make a tour of the clubs and collect them. But, to date, the Calendar certainly is an interesting one—we will have to give up working to attend them all—every month has its big event—this does not include the local inter-club meets. Red Bank M.Y.C. suggests the Eastern Division being rearranged into four sections for some of the Selection races, such as the preparations for the 50800 National Championships—the Eastern area has grown so that we will have to work out some plan to give the Host Club in the Eastern Trials and the National event some show to make a race of it. The thought is good, but gosh! how will we attend the events now scheduled—and the news of the growth of the sport is gratifying—if it keeps on, where will it all end> If our friends from across the ocean take the new 50-800 Trophy home with them, we will probably never see it again on these shores—it’s a swell bit o’ nautical work. A skipper, who has just been selected as a Club Measurer wants information on “ dry ”’ measuring a model—many Club Measurers can stand a lot of assistance via the various accepted methods of measuring—this scribe wonders at the system used in many cases. I am thinking of sail area—no ulterior thoughts—just that the thought suggests itself as to how closely boats are measured in ordinary Club routine, and how accurately in Inter- VANCOUVER MODEL YACHT CLUB NEWS The Vancouver Model Yacht Club wishes to re- port great strides in the model yacht racing game, and the 1937 season augurs to be the best ever enjoyed by the club. In International competition with two clubs representing Bellingham and Seattle, Washington, U.S.A., and the other local club, the Vancouver Model Yacht Club won two of the major events out of three, in which it had entries. Practically all of the 1936 club events were won by the scant margin of one or two points. An International A-class model from Prince Rupert was a visitor during the summer months, the boat being the ‘* Talisman.’’ During the Canadian Exhibition races at Toronto, Ontario, the club was represented by the Commodore’s model ‘‘ Robin.” We have had the honoug of having our Commodore elected to executive office in the newly formed Canadian Model Yacht Association, and we are looking forward to a great future for model yacht racing in Canada through this body. Our present fleet consists of five International A-class models, 14 D-class models, two 50-800 build- ing, and we are looking forward with keen interest to the building of several 6-m. models, which class was adopted by the Canadian Model Yacht Association as an intermediary class. H. ScIARINI, Sec.-Treasurer. 332 . MARINE CORRESPONDENCE SHARPIE DESIGNS—FOR AND AGAINST Dear Sir,—I read with interest your notes on Sharpie Designs, but still would say that, in my opinion, they are not yachts, and should not be encouraged. I think we could well follow our elder brethren, who have formed rule after rule to prevent freak yachts being built. Rules are made with one intent—that of providing really serviceable, weatherly, fair-proportioned and good-looking yachts —freaks being discouraged. The Sharpie, all said, is nothing more than a freak yacht, an ugly contraption built for speed with nothing else in its favour. Labour cost would be practically the same in both cases, cost of materials of small difference, while the one is a yacht of beauty of form, the other a square box pointed at the ends—an ugly sight on the water, and worse out. I note with pleasure the articles once again by ** Yardstick,’’ the writer who has his own clear, MODELS are now helping in the formation of a model yacht club at Liége, and one at Ostend will be founded next Sunday. So you see model yachting comes into favour in Belgium—sailing as well as power boating, in addi- tion to models of sailing ships and historical vessels. A Federation will shortly be set afoot handling everything connected with marine models so as to get some unity in the different sections. Yours sincerely, G. HEYDT, Antwerp. simple, understandable way of giving the pith of things from the bottom upwards. H. L. AsH. Editorial and Publishing Offices : 52, FETTER Dear Sir,—The letter re Sharpies, from one of your readers, portesting against your encouragement of them, needs replying to. Wherein are they not proper yachts? Does the fin-and-skeg on an A-class International Racing Model make her a proper yacht? Obviously, no. Must we all, then, have full-keel boats in order to satisfy the writer protesting about one particular design of hull? I don’t think so. The *‘ Islander,”” Harry Pidgeon’s ocean-going Sharpie, proved that the hull was a real, sound yacht, and stood up to every one of the seven seas, and came home smiling, so I for one do not understand the gentleman’s protesting against an obvious proof as to her yacht-like lines and construction. I am building a 5ft. replica of the ** Islander ”’ to scale, and shall prove her worth at Easter, | hope, in the sea as well as on our pond here. I[ am adopting fin-and-skeg instead of her full keel, and making a few other slight modifications for model sailing purposes. From her lines it is quite obvious that she will be fast and thoroughly reliable. M. C. JOHNSON, Eng.-Captain, R.N. MODEL YACHTING IN BELGIUM Dear Sir,—You will, perhaps, have wondered occasionally how model yachting is going on in Belgium. We may say that we have had very hard times over here, but now we are slowly coming up again. Our members are starting anew with much energy, and, if we have some luck with our sailing water, we will have good sport this year. In the meantime, we have not been idle. On the contrary, failing to have enough water for sailing Antwerp M.Y.C. 2, Place de la Comedie, LANE, LONDON, E.C.4. Telephone: Central 9914. SUBSCRIPTION RATES Inland, 7s. 6d. per annum; U.S.A. and Canada, $2. Overseas, 8s. 6d.; EDITORIAL Contributions, Correspondence and Club News intended for publication must reach our Offices not later than the 16th of month previous to publica- tion.. The Editor does not undertake to publish all matter received. Where a nom-de-plume is used, correct name and address of sender must be enclosed. The Editor does not undertake responsibility for photographs, plans, or articles submitted, but every care will be taken to ensure their safety, and we will endeavour to return same if postage is enclosed. TECHNICAL ENQUIRY BUREAU Queries involving technical matters will be referred to the experts in charge of various departments of this Magazine. Long technical replies cannot be given unless a fee of 2s. 6d. is sent. Enquiries necessitating an answer by post cannot receive attention unless accompanied by stamped addressed envelope for reply. ADVERTISEMENTS Terms on application. Special rates for Club Announcements of Regattas, etc. SMALL PREPAID ADVERTISEMENTS Private advertisements for our For Sale and Wanted Column are charged ld. per word. Minimum 2s. craft, we have pushed our steam and motor section, Box numbers, c/o MARINE MODELS, can be used if desired at an extra fee of 6d. be relied on to perform as they ought to do. We devoted ourselves also to guide and help the Brussels M.Y.C., a new club born a year ago, and All advertisements must be received at our Offices not later than the 16th of month prior to publica- where a lot had to be done to get boats that could tion.