The Model Yachtsman: Volume 2, Number 10 – January 1930

YACHTSMAN) | HODEL PRICE ey} i SAIL & POWER Vol. 2. Yo. 10. | HE January, 1930 NEW YEAR’S GOLDEN GREAT NUMBER HOUSE, PULTENEY STREET, LONDON, W.1. ; lla TRE YACHT MODEL ra ‘3 _~ A Vol. 2. No. MONTHLY MAGAZINE aay 22a FOR MODEL YACHTSMEN. 10. JANUARY, OUR RACING 1930. CLASSES. By Moeanpor. HE revision of Rules will figure on the Agenda time. It is interesting to note that many of the for the Annual General Meeting of the Model By a very wise arrangement earliest boats built under the rule are still able to Yachting Association. put up a good show in competition with the latest it has been decided to incorporate in one book all rules for which the Association itself accepts direct responsibility. Rating Rules, which are formulated by other bodies (viz., the I.Y.R.U. Rule and the I.M.Y.R. Association’s formula for the A-class), creations, and anyone: building to the class can be assured that his boat will have a long and useful racing life. both in The class is popular in many clubs, and England and Scotland clubs formed specially to cater for this class. have been The Scot- are printed in separate books so that any alteration tish Club is a very young affair, having only come in- made in them by the responsible authorities will not affect the M.Y.A. Rules or necessitate further to being a few weeks ago, but it has amongst its re-printing before the next revision is due. sive modelmen in Scotland, and should do very well. members many of the most influential and progres- One of the most important questions that will The most. numerous class of model in England is come up for decision in connection with the revision will be the list of classes for national recognition. the 10-rater. In a way this is a class apart from other models. It is much the oldest class that we have, being built under a rule formulated forty odd Racing classes can be divided into the three cate- gories of International, National and Local, but only the National Classes come under the jurisdiction of the M.Y.A. Of course, an International Class can also be a National Class, and it is well this should be so, as it ensures a strong fleet. from which to select an adequate representative for an International Race. ; Actually, we have only one international class. of model recognised by the International Model Yacht Racing Association. This is the A-class, measuring l-metre (39°37 ins.) under the I.M.Y.R.A. formula. Undoubtedly this is the best class we have ever had, and there is no possibility of a change for a very long years ago, but that is not necessarily a disadvantage except to those who like to be in the latest fashion. The Length and Sail Area rule was invented for real yachts and proved a great advance on its prede- cessor, the 1730 rule, under which the “ planks-onedge ’’ were developed. The Length and Sail Area rule produced an entirely different type and the first boats under it were very handy crait. The possibility of obtaining additional sailing length by reason of the unmeasured overhangs, however, soon led to the introduction of the scow type, and overhangs became longer and longer. This eventually led to the abandonment of the rule in the prototype 174 The Model Yachtsman. for open-water racing, but it still continued upThames where the classes of l-raters and }-raters continued to give much satisfaction. After the rule was discontinued by the Y.R.A. it was taken under the wing of the 8.B.A., which caters for the sport on these inland waters. One of the great difficulties in these lightly-built skimming-dishes with their long overhangs is to keep the boats from hogging and consequently lengthening their water- line. There have been no new boats built to the class for many years, and the 8.B.A. has now decided to rate them by sail area alone. Thus the only survival of the Length and Sail Area rule is in models where the 10-rater class continues to flourish. This is not to be wondered at since the 10-rater is a very nice boat and highly suitable to certain waters, particularly inland waters of limited extent. January 1930 (1-in. to ft.), 8-metres (1}-ins. to ft.), and 6-metres (1-ins. to ft.). Two reasons were given for this recognition. The first was that the classes were not then individually strong enough to get any real racing and the second that the ““ Combined Classes ”” would afford an opportunity of testing which of these classes was the best, with (if the writer’s memory does not play him false) a proviso that at the end of the period of test, the best of the three was to be adopted. Now there are practically no 8-metres so that class may very well be left out of reckoning. There are a certain number of 10-metres in England and Wales, but to-day there must be almost as many 6’s. Many of the more recent 10’s have also been built with an eye on the possibility of the 6’s being ultimately selected and have sufficient displacement to allow them to rate as 6’s. Also the rule is very simple and easy of compre- In Scotland there is a very numerous and up-to-date hension, whilst the boats are light and portable. They certainly require skilful building as light fleet of 6’s, but no 10’s. Owing to the fact that the boats were sailed up to last season without crew weight, there was little to choose on season’s results between the 10’s and the 6’s, but with the addition of the crew weight the scale should be turned in favour of the 6-m. The 10’s are somewhat deficient as a model in draught, whilst the minimum displacement is rather high in the 6’s. Actually the writer does not feel that the average 6-m. model to-day represents what can be done under the rule, and probably a model with a l.w.l. of about 38 ins. (lengthening to 39 ins. with her crew weight aboard) and carrying something over 1,200 sq. ins. sail will be eventually evolved. construction is essential in order to get an adequate amount of lead on the displacement. The rule has been brought up-to-date as regards Sail Area measurement in all respects except batten limits, and it would not mean much to bring it into line with other classes in this respect also. The class is purely a national one and model yachtsmen are in a position to please themselves what they do. The next group of classes are the I.Y.R.U. metre classes. The formula for these is settled by the International Yacht Racing Union, and model yachtsmen have no option but to adopt whatever changes and adjustments are made by that body. The classes and scales on which they are built are, however, in the jurisdiction of modelmen them- selves, and as these classes are not recognised by the I.M.Y.R.A., British model yachtsmen can decide these matters without any reference to anyone else, and they are purely national classes. The largest of these classes is the 12-metres, and there is a numerous fleet in Scotland. The boats are only a trifle smaller than the A-class, but lighter in displacement. The prototype 12’s are beautiful boats, but the model is rather too light in draught. In England the class is eclipsed by the A-class as the difference in size is small, and the great interest aroused by the International Model Races and British Championship attracts recruits to the class. It is not every man who has the physical strength required for handling these large and heavy models, and all waters are not suited to them. Even when the water is suitable a boathouse within easy reach is essential. Hence there is a natural demand for a smaller, lighter boat also. At this point the writer feels certain that he will be accused of propaganda, but actually he is pointing out hard facts and leaving model yachtsmen to draw their own conclusions therefrom. If this be propa- ganda then he pleads guilty. Several years ago the M.Y.A. recognised the “Combined Classes ’’ for a limited period only. The classes that came under this head were the 10-metres Now the exact position with regard to the “Combined Classes” is this. Both 10-metres and 6-metres are recognised as separate classes; they are also recognised as units of the “ Combined Classes.” The main object of instituting the “Combined Classes” was to determine which was the better, and the set time for decision has now arrived. Model yachtsmen will, therefore, have to make up their minds. The alternative to this is to admit that the “Combined Classes” give satisfaction as they are and keep them on, but if this is done it must be remembered that there are no ‘“ Options” as to draught and displacement in the I[.Y.R.U. rule. By an ingenious arrangement of scales the model yachtsman has brought the models of three different LY.R.U. classes out the same size, but by recognition of these three classes as one “ with options,” he entirely alters the characteristics of the tormula, and in fact creates a new rule which is entirely different to the I.Y.R.U. Rule that it is supposed to represent. To call this an I.Y.R.U. class is wrong, and a new title is needed. What are model yachtsmen going to do about it ? The 18-footer class is another class of approximately the same size as the units of the ““ Combined Class,” and actually when the 18-footers have met 6-metres or 10-metres, they have held their own comfortably. This was, however, before the introduction of the crew weights in the metre classes, and January 1930 The Model Yachtsman. a 6-m, as outlined above should be able to more than hold her own as she would be a more powerful craft. It may be added, however, that some of the best 18-footers would rate as 6’s with very slight alterations. The history of the 18-footer class is of interest. During the War when all big boat racing was at a standstill, Major M. Heckstall Smith (who was also responsible for the I.M.Y.R.A. Rule) invented the 18-ft. formula. This was intended for a class of real yachts smaller than the 6-metres. No real sailing was possible, but in order to try out the formula, the M.Y.S.A. (one of the oldest model yacht clubs with headquarters in Kensington Gardens) built and raced models to the class. These turned out extremely fine little craft. Aiter the War, the Boat Racing Association, which was formed to encourage small boat sailing, took the rule up. The rule was subsequently adopted by the I.Y.R.U. and limits imposed. Only a very few boats were built as they proved too small for the Solent waters, and after a few years the class was dropped by the I.Y.R.U. In the models the class was adopted by the Model Yachting Association. Although most excellent models, the class unfortunately did not take on outside the club where it had been born. Here and there a few were built but gradually the class has lapsed and the National Championship has not been contested for several years. In spite of the fact that we have so many classes, there is one very great omission. Nothing smaller 175 bearing in mind the difficulty of measurement and that much of the racing will be held by seaside authorities, it would seem clear that the very simplest formula is needed. Waterline length always presents difficulty when proper appliances are not to hand, and therefore l.o.a. should be taken. This in itself will not be sufficient or we will get outrageous boats. If 36-inches l.o.a. was adopted, we might have boats with 25 lbs. displacement and, somewhere in the region of 1,800 square inches of sail. The writer would, therefore, suggest a dis- plagement limit. By fixing this sufficiently low, both the form of the boat and its sail area would be limited, especially if a restriction was also imposed on draught. As this would mean finding the waterline, it might be better to make it depth from deck to keel. Beam might also be limited. Sail area is difficult to measure for a seaside authority, and by limiting the hull, s.a. might be automatically limited. The writer owns that he would prefer the three restrictions of l.o.a., s.a., and weight, but foresees difficulty in getting the sails measured. The alternative would be l.o.a., beam, depth, and weight, and let as much sail be carried as the boat will stand. As an example, and as a 36-ins. class is obviously needed, the writer would suggest the following limits :—36-ins. l.o.a., 10-ins. beam, 10-ins. depth, and 12 lbs. weight. The final conclusion. reached after a survey of the various class is that we have too many classes of approximately the same size. It is not possible for than the 10-m., 6-m., and 18-ftr. size is recognised by the M.Y.A. Undoubtedly such a class is wanted the A-class to clash with a 36-in. l.o.a. class, but urgently and this rule revision gives a great oppor- where there are several classes of approximately the tunity for its adoption. At many seaside places there are races for boats of this size. There are small ponds where they are just what is needed, and, above all, there is the necessity of something suitable for the juniors. Whilst the Imperial Junior League caters for the youngsters, it is essential that the British National Authority should also recognise their existence and formulate a class for them. What guise this should take is open to discussion, but OUR BURGEE of a Burgee suitable for use by the Model Yachting Association. The prize of one guinea was donated by Mr. H. G. Pyne, Hon. Secretary of the Solent M.Y.C. The Competition was judged by Mr. John A. Stewart of the West of Scotland M.Y.C., who is a well-known authority on heraldic matters. We have to thank Mr. Stewart not only for judging the competition, but also for the excellent report Tne prize design is by Mr. G. W. Munrve, I8, Sutherland Street, Hillhead, Glasgow, to whom a cheque has been sent. The winner has contributed many capital drawings to our pages. I think Tt will eventually have to be solved by the majority, The writer has carefully avoided expressing any personal opinion and has simply stated facts as they are, and unanimity is for the benefit of the sport. leaving readers to ought to be done. DESIGNING S will be remembered, it was suggested that we should hold a competition for the design appended. same size, undoubtedly interest is divided. all modelmen will agree on this score, but every one of us would wish to retain his own favourite class. decided for themselves what COMPETITION. JUDGE’S REPORT. It has been a pleasure to judge the designs submitted in this competition, and by careful elimination to arrive at a decision. I award the prize to the design of Mr. G. W. Munro, as, in my opinion, it best fulfils the stipulated requirements, If accepted by the M.Y.A., it is to be hoped that it will not excite unrighteous envy on the part of the Y.R.A.! The three crosses marshalled by the Act of Union are known throughout the world as the flag of Great Britain and Ireland and the British Empire. In the standards of the 15th and 16th centuries the cross of St. George or of St. Andrew borne next the staff indicated the nationality of the bearer, while the 176 The Model Yachtsman. personal badges were displayed in the fly. The red saltire is sometimes questioned ; but in ancient times it appeared in the arms of the FitzGeralds ( Hibernis ipsis Hiberniores—more Irish than the Irish them- selves), and in the order of St. Patrick, 1783, prior to its inclusion in the Union flag of 1801. January 1930 W.F.B. sends a sketch which is well-intentioned but far too complicated to be effective on a burgee. No. 1251158 is a burgee of St. George (white with a red cross), with St. Andrew’s cross on a blue blue canton. An Anglo-Scottish combination, effective in its way, but not so fair as the first Union flag of 1606 and 1707. L.C.W.—Another burgee of St. George with a model yacht thereon. This might be suitable for an English model yacht club. A.E.F.—A red and blue burgee with two silver stars. Suggests the Aberdeen line with an extra star, or an American club. An effective design all the same. a In Mr. Munro’s design the Union is in the right place, the crosses are nicely proportioned, and the fimbriations are of the same width throughout the flag, as they ought to be. OO The Admiralty badge is a gold anchor on blue, and in this design the anchcr has rightly been altered to silver. In effect, this is the burgee of a British club or association with authority, but not the Admiralty. The normal proportions of a burgee are 2: 3, so that a height of 3 inches would give a length of 43 inches, and RE – 77 D 7 KRRRRRKPSSA so on in proportion. E.G.E.—White with a red cross surmounting a blue roundel. The roundel is is quadrants separated from the red cross by the white field. Some of the English model yacht clubs might consider this design. N.C.—A red burgee with a white pheon or arrow thereon. H.S.—A study in black, white and yellow. A gold yacht on a silver field is not good armory. The field might be blue and the wavy bars might be white, giving the usual representation of water. A few words on the other designs may not be out of place. Mr. F. W. Plews submits an attractive design showing the three national crosses on separate shields. For the present purpose I prefer to see the crosses blended in the constitutional manner. Quis Separabit ? Like the winning design, this is a work of careful draughtsmanship; but it is a decorative design rather than a burgee. H.E. (non-competitive) —A burgee of St. George with a blue lozenge bearing St. Patrick’s cross on the top of St. Andrew’s cross, or a red saltire with white edges. Ingenious, but not equal to the Union crosses. T.E. (non-competitive). Described as “a red burgee bearing thereon a device in white with blue quarterings such that the white device is left as a circle with a cross, this being the sign which the olden shipwright was wont to chalk on his mould for the midship (or master) section. The red, white 177 The Model Yachtsman. January 19380 and blue are the British national colours.” Perhaps this could be blazoned—Gules, a roundel azure fimbriated argent, surmounted by a saltire of the last. One of the simpler and more effective of the designs; it might be most appropriate for a Little >? Ship club. The present system of indicating colours by means lines drawn in various directions, and of distinguishing gold by small dots, is said to have first been used by Petra Sanctain a work published in 1634, and it is the survivor of many which were devised in the early part of the 17th century. It is an inartistic device, except perhaps when applied with discretion in fine line engravings, and in strong line work it is best avoided. When colour must be indicated, as in this competition, it is better to adhere to the known system rather than to invent new systems as several competitors have done. The proportions of crosses and other charges iin relation to the field is a matter of importance in armorial of design and will repay study. Joun A, Stewart. a af el ef ee T nes = ee In \ a SSS oe === ims, Tat See be ———— IN THE MIDLANDS. MODEL YACHTING AT BOURNVILLE. Since its inception in 1923 the Bournville M.Y.C. developed steadily, and several oi its members have since taken an active part in the formation of the Birmingham M.Y.C. Racing for the Walter Edwards Challenge Shield took place on October 12, when seven boats of various types competed for the shield and other prizes. The sunshine and a moderate westerly wind, following the heavy rain which filled the Rowheath Pool almost to overflowing after the prolonged drought, made racing conditions ideal. The old 5-rater models which formed the Club’s original fleet received four seconds’ start from the more recently constructed 36” models. The result was uncertain until almost the last race. Mr. G. Beale, Jnr., and Mr. J. W. Edwards (son of the donor of the trophy) won all their heats up to the point of meeting each other, when Mr. Beale, sailing a 36” model, managed to get in ahead of Mr. Edwards, and thus secured the trophy. On the following Saturday most of the competitors met again to race for the Davey Vase, which is at present restricted to 5-raters. The competition was again keen and resulted in a victory for Mr. W. H. Davey, the Commodore of the Club. i 19″ 0 al , es Y Re 32 a 48 . 40° i) Pa Sail Plan of * 10-Rater Model ‘Flying Designed by A. W. LITTLEJOHN. The lines of this powerful 10-rater were published in the December number of THE MODEL YACHTSMAN. Blue prints giving lines half-size with full-size plan are available for 12s. 6d., a set, post free. section Spray.” 86… The Model Yachtsman. January 1930 AOTIAS UETIES rarenalonith ! fl TWO QUERIES AND A IMPROVING THE L. SUGGESTION & FOR S. A. RULE. I should be obliged if you will inform me where I can obtain the “ Certus”’ or other good brand of Casein Glue as recommended in your columns and how it is sold as no one about here seems to know anything about it. I am just starting a scale model of a design of mine which appeared last year in the Yachting Monthly. The boat is square-sterned and the rudder is hung ‘“ outdoor,” so I would like to know if it is possible to fit a Braine Steering Gear and how to make it operate thereon. T have noted in your columns much prejudice against the old L. & S.A. Rule, but the worst its opponents have to say against it is that (a) it is obsolete and (b) that its adoption for a fresh class is a retrograde step. to me to be a Those who write thus seem trifle illogical as most of them no doubt use the (so-called) new fashioned Bermudian rig, forgetful that it is even older than the L. & S.A. rule being nothing more than a development of the very old “leg-o’-mutton”’ sail, and further was a rig used more than forty years ago on a famous class of dinghies in Bermuda, whence its name is derived. True, it has been improved and brought into line with present day hulls, therefore nothing prevents the same being done to the old L. & S.A. Rule. Better pens than mine have lauded its merits and the fact that the 10-rater (and in some parts the 15-rater), is still going strong is proof of its worth. I am not decrying the beautiful creations from other rules, on the contrary I admire them, but there must be many such as I, who look with awe at formule they cannot grasp, and are either too old or have not enough time to learn. To them the L. & S.A. appeals and may tempt such as can draw a bit to chance their hand. In the smaller prototypes the rule developed extremes that killed it, but I believe this might have been avoided by restrictions. My suggestion is merely to take the rule as it is and add the following restrictions :— 1. Overhangs not to exceed 3 of L.W.L. 2. Beam and draught added not to-exceed 3 of L.W.L. 3. Displacement not to be less than 1 Ib. for every (let us say) 70 sq. ins. of sail Example :—L.O.A. 714 ins., L.W.L. 44 ins., Beam 14} ins., Draught 13 ins., S.A. 200 sq. ins. Rating 13.33. 3 of L.W.L. = 27} ins. + L.W.L. = 71} ins. L.0.A. 2 of L.W.L. = 274 ins. shared between Beam and draught. 2,000 sq. ins. S.A. divided by 70 = 28.57 lbs. for displacement. Many 10-raters have been built carrying between 80 and 100 sq. ins. of sail to the pound of displace- ment, therefore, I think that my suggestion would compel reasonable dimensions and weights. Personally I do not see the need of being bound strictly to prototype dimensions when models are admittedly made to sail under very different conditions. ENTHUSIAST. REPLY. We believe that ‘“Certus” Glue is stocked in small tins at most of Messrs Hobbies’ branches. Mr. W. J. Daniels (see Advertisment can supply Casein Glue. columns) There is no difficulty about fitting a Braine rear The only difference is in the quadrant used which has the tail on the fore side. The elastic centering line operates on the fore to a square stern boat. side instead of abaft the rudderhead. The pulley blocks and steering sheets are fittedin exactly the same manner as usual. If ordering from a fittings maker it is necessary to specify that the gear is for use with a square-stern craft. The suggestion with reference to the L. & S.A. rule is of interest. Worked out on the basis of a 10-rater, it would give a craft of 40 ins. L.W.L., beam 13 ins., draught 12 ins., L.O.A. 65 ins., s.a. 1500 sq. ins., displacement 21.43 Ibs. Possibly .ome of our 10-rater friends. might like to express their views on this suggestion in our Correspondence Column ? THE ‘“‘YACHTING MONTHLY” CUP. Can you inform me of the conditions under which the above Cup is held? DICK WHITTINGTON. REPLY. The original Cup was won outright in 1925, and the present Cup donated the following year. The competition is ofen to all nationalities belonging to the I.Y.R.U. and the U.S.A. It is held for the year by the winning Club, but can be won outright by being gained three successive years by the same Club represented. by same owner. The races are held under I.M.Y.R.A Rules at the time and place selected by the country that holds the Cup for the time being. The A-class is used, and yachts must be designed, built, owned and skippered by persons of the nationality represented. Skippers and mates must be amateurs. PROPELLERS. (concluded from page 172). AVITATION has been the bugbear of speed “ craft designers since the days when Thorneycroft turned out the first torpedo craft. Experiments then made proved that this difficulty could be largely overcome by means of a suitably designed propeller boss. The best results were obtained with a long torpedo shaped boss of relatively very large diameter in comparison with the total diameter of the propeller. The modern engine, whether reciprocating, turor internal combustion, relies largely on obtaining a high rate of revolutions, and consequently gives relatively greater power output bine By A. BRAcKETT. How far this Contrapropeller would benefit a speed-boat like a hydroplane, it is impossible to say, but it would appear that the device is well-worth trial. The writer gives a drawing showing a method in which it might be applied in a three-blade form. Suaaestion FoR APPLICATION OF for its weight and size. Unless this gain is to be largely offset by cavitation losses, gearing down has to be resorted to and propeller design carefully studied. TO A SPEED-BOAT tired Sta Ee ES ConTRAPROPELLER Mention has repeatedly been made of losses owing to the rotation of the stream thrown by the screw. aL Any means to mitigate this are worthy of consideration. One of these was the Thornycroft jet propeller. Another which would appear to be highly successful is the Star Contrapropeller. This device consists of fixed vanes just abaft the propeller set at an angle to gain a forward impulse from the rotation of the propeller jet. It is claimed that in a cargo steamer on which this was used the saving in power averaged almost 20%, whilst the vibration was decreased and steering improved. SSA The most useful application of the Contrapropeller is to steamers when it is usually made in a fourblade form. The stern-post forms the up and down blades and a member at right angles to the sternpost forms the other two. == SCREW TT ON 187 SS METS. The Model Yachtsman. Sle ee January 1930 This device has also been Aerer ConrrRaPRoPetter tried ahead of the screw giving a contrary twist to A-A. the feed stream before it reaches the propeller and also to extract a forward thrust from it. It is claimed that this results in a further improvement almost equal to that of placing it aft of the screw. UPPER B, VANES Lower VANE ForwarD ConTRAPROPELLER FRoPeLLeR Jet SHOWING Notatory Action. C-C. UPPER VANES. D. Lower Vane. E. UNIVERSAL JoinT. F. PROPELLER GUARD. Finally it may be said that in spite of the fact that the screw propeller has been in use many years, very little is yet known about it. Even to-day the costly method of full-size expcriment is tried on real ships, and often several propellers are fitted before the correct one is found. The model power-boat enthusiast need not feel discouraged if he has to make a number of propellers and experiment deeply before he finds out what suits his boat and engine. The whole science of propeller design is up in the air, and theory does not always tally with results. experimenters At and the same time the work of mathematicians must not be derided as a knowledge of their discoveries will help us to an understanding of results obtained and an avoidance of many sources of difficulty. Yet nothing so far discovered will absolutely put us in a position to calculate a propeller and say definitely that we know exactly what propeller any given craft will perform best with. 188 The ao Ss ee Model Yachtsman. oe The Editor accepts no responsibilty for opinions expressed by Correspondents. Letters intended for publication must be brief and to the point. They should not exceed 500 wordsin length and must be written on one side of paper only, Correspondents are requested to read our note on this subject on inside of back cover. THE A-CLASS. A SIMPLE APPROXIMATE FORMULA FOR MAXIMUM SAIL AREA. Sir, For the purpose of this letter, formula as follows :— L+ v8 Lv8S a 4 | quote the Rating second term then becomes §8/2.664, and the re- sultant equation is 25 L + .625 VS = 39.37. This is easily memorised, observing that the coefficients of L and vS are } and 3 exactly. For practical use the equation is best written VS = 63— 0.4 L. = 39.37 12D For the absolute maximum. sail area for a given value of L, D must have the greatest value allowed by the rules, i.¢., (0.2 L + 1). If this is substituted for D in the second term of the formula, both L and D disappear from that term, and the equation contains only L and ,8. The resulting equation is however too complicated in form for practical use, due to the fact that ‘D is not exactly proportional to L, although nearly so, for values of L ranging from 42 to 50 inches. ARCHD. 231, Strand, W.C.2. SHARP. THE RIGHT IDEA! Dear Sir, We of the newly formed Bedford M.Y.C. wish your paper every success, and are doing our best to get every member to subscribe. We hope to be able to furnish you with a report of our meetings every month next season. Yours faithfully, If D = .222 L be substituted in the equation, the greatest error in the value of D for the above range of values of L is less than one per cent. The D. B. WELLAND, Commodore, Bedford M.Y.C. 110; Gladstone Street, Bedford. Section Plan of “Flying Fish,” oe Metre—Hydroplane. Designed by Rue. W. Lance. 7 (TTT wall tL WW | One-third full size. The lines (cne-sixth of full size), appear on page 189. —— SS Joale «2 taches Half-size blue prints (Section plan full size) are obtainable from THE MODEL YACHTSMAN for 4s. 6d. a set, post free. SSS TS Dear Mr. Editor, I read with great interest the article appearing under the above title in the SS x UY November MODEL shaft. The results marvellous, and I should like to put this point forward for consideration of | model power boat men. ettitthe i I think when one considers this | angle of shaft business, it will be seen | that the advantages of a fairly acute angle fairly outweigh the horizontal | line aimed at by most designers. At any rate, ‘the proof of the pudding | | i being in the eating,’ I must leave the point for our friends to experiment with. | Referring to the hydroplane design \ at . TMm e ‘ / designed some time ago for a friend and this model fitted with quite a small power-plant gave exceptional] results. Perhaps some of our friends may care to try her with bigger powers. Yours faithfully, Rea. W. Lance. 11, Haslemere Road, East Southsea. n See REG W LANCE. —— OESIGNED BY ‘ —— ” FISH inches Joate in FLYING “ —— METRE- HYDROPLANE (a \ published in this number, this was ° = Mr. Lance’s point is an interesting one and we hope that some of our other readers will have something to add to the discusston. The design referred to is published herewith, and shows a very pretly craft which should have great possibilities. We hope she will be built to and tried out with a fairly hefty plant. It will be noticed that she embodies many of the features suggested by ‘A Model Yacht Designer’ in his article. Mr. Lance has had considerable experience in the designing of power craft, but is best known as the designer of the International Champion “Little Nell,” (A-class). He gained third prize in our First Designing Competition. Editor, The M.Y. onbed PT of Ez iS SOE Sil ‘ angle obtained with very small engine were ca- Cbs a “Viper” type hull and an extremely acute x < TM TESTS SES Now several years back the Americans experimented with SiGe propeller. ..... * i/ | Gupwate —t VENT To sTee | THE I have picked out for discussion viz: ‘‘The down pull of the ii] | of One portion of this article which y/ Y j issue YACHTSMAN. aE Ee PROBLEM OF MODEL HYDROPLANE DESIGN. SE THE SSO ES 189 — The Model Yachtsman. ae January 1930 190 The Model Yachtsman. January 1930 success and the simple rule will in all probability A SAFETY DEVICE FOR MODEL remain for ever a Will-o’-the-Wisp. SPEED BOATS. Sir, Re Windjammer’s letter which appeared in your November issue, he suggests a device to stop boats which break away from. the line attaching them to the pole. The following is an idea which I think would work admirably : For usr with Prrrot Boats, a lever pivotted at A is held in two spring contacts BB, inserved in one of the battery leads, by the hook D being hooked under the line F just outside the spring-hook C which attaches the line to the side of the boat. Whilst the line remains taut the level is held in position, but should the line slacken or break, the spring E will pull the lever out of the forward spring clip thereby breaking the circuit. The ‘“ B” class is something quite different and distinct, and should be considered solely on its own merits. This class is to be given international status, and it would appear desirable to work to a popular and well-tried current full-size rule and build to a reasonably large scale. Consideration must be given to the fact that the final product must be small enough to be carried “* en voyage ”’ without undue fatigue, yet sufficiently large to give good sport, and there is only one rule and scale in conformity with these requirements. The LY.R.U. 6-m. is an undeniably popular class and a scale of 13 inch to the foot produces a handy crait with sufficient displacement and draft to give seaworthiness and reliability in any weather. In adopting this rule the question of vested interests would not arise as there is already a considerable fleet of these excellent little ships in being. Finally, regarding difficulty in designing and measuring—surely the “A” class is no easier ? SAFETY DEVICE... For Use witu STEAM Boats, instead of pivotting the level at A, it should be fixed to a plug cock inserted in the petrol pipe of the blow camp whith should be fixed in the boat, when the breaking of And the popularity of the “A” class is beyond question in spite of the allegedly complicated formula. Yours very truly, MERCURY. “ Kodai,” Farm Lane, Purley, Surrey. the line will turn the petrol off. Alternatively the plug cock could be inserted in the steampipe and a safety valve boiler. fitted to prevent damage to a flash As a power boat man, I greatly appreciate the friendly spirit which is growing up between yachtsmen and power boat men. Wishing your paper every success. Yours secretary, J. P. OAKLEY, Chairman, West London P.B.C. 33, St. Mary Avenue, Wallington, Surrey. B-CLASS. Dear Sir, Since I wrote you last there has been considerable controversy around the suggested ““ B” of which has left us in statu quo. class, all Unfortunately this matter has in many cases been confounded with the demand for a simple rule intended for the younger generation. We have now a very strong and able body in the Imperial Junior League and I am quite sure that this question may safely be left in the League’s hands. A sound, simple rule can only consist of restrictions! The THE B-CLASS MODEL YACHT. Sir, In your November issue, Mr. E. Mark Robinson puts forward the sound reason for bringing such a class into being, i.e., its size and portability, enabling easy transport between countries. Does Mr. Robinson know that at the last meeting of the I.M.Y.R.A. at Gosport our French friends were in favour of the adoption of a class to the T.Y.R.U. Rule? Quite a number of British modelmen favour this rule also, but our delegates were instructed to press for the postponement of the adoption of a B-class on the ground that the time was not quite ripe and that it would be unwise to divide the interest with the A-class. When the time for the adoption of a B-class does come, the fact that our French confreres favour the 1.Y.R.U. will have to be borne in mind. With regard to the three formulae put forward by Mr. Robinson, I have tried various constants but found them faulty. Will Mr. Robinson please tackle this constant himself and see where it leads him ? Yours truly, W. F. Benenna, Commodore, Solent M.Y.C. best yachting brains in the world have been seeking this Ultima .Thule for years past without complete ** Montpelier,” 57, Stubbington Avenue, Portsmouth. Printed and Published for the Proprietors by H. G. STONE, Town Green, Wymondham, Norfolk, January 19380 Why not have YOUR Fitting Chas. Out done by a Practical Model Yachtsman ? 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The Model Yachtsman. January 1930 The Model Yachtsman. | c 61 WALKERS 61 Why not let your New Year’s Present be a nice Model Yacht or Power Boat ? “K” SAILING YACHTS 5/6, 8/6, 10/6, 146, 17/6 and 35)/-. “K” POWER BOATS 87/6, 12/6, 16/6, 21/-, 27/6, 30'-, 50/- and 60/-. (Clockwork and Electric) SPECIAL OFFER. Constructional Sets to make up your own Boats, complete with plans and full instructions: Sailing Power Boat Boat a (Clockwork)... Na 14/6 14/6 and 21/- Dl ee ee BURTON BOATS 31/6, 42/-, 59/6 and 75)- Special Yacht Models constructed by us by Mr. George Braine, full £8 specifications and £12. see previous oe For issues. 61, Baker Street, London, W.1. WELBECK 8835.