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LS : : = . . fer might be expected by the choice of name for this new “M7” class boat, through- out the design the keynote is on dynamic balance in order to achieve the best possible performance to windward. As a rule a new design does not usually turn out quite as first intended as more often than not various unforeseen factors combine to modify the lines to a large extent, but with Dynamo the completed design adheres very closely to the original conception, although the displacement at 22.5 lb. is rather more than was expected, considering the very moderate proportions of the hull. Nevertheless all the original require- bags os ments have been met, not the least of which was the intention to keep the fin as far aft as possible in order to allow the root to fit snugly into the wave hollow, thus assisting the huil balance though at the expense of a little stability, since this means that the lead must be placed in the fin leading edge rather that at maximum draught. However, it would seem that pendulum stability is by no means the only force helping to keep the hull upright and it may be noticed how most yachts show a tendency to come upright when driven hard. This is probably due to the hydro. forces attempting to equalise pressure, and therefore symmetry on either side of the centre line, and the effect is particularly noticeable when running before a strong quarterly wind when most models, especially those capable of planin g speeds, come upright or very nearly so, even though the lateral component of the wind pressure is obviously being only partly compensated by the weight of the keel. ’ The balance as a whole has been divided into four separate sections with the intent ion of securing a reasonable degree of balanc e in each. These are firstly, ordinary static hull balance, which in the design shown is quite good owing to the easy type of section used together with the moderate beam and long waterline. Secondly, dynamic hull balance in which the positioning of the appendages is of prime im- .wersonnn as PLANS Ro caeetnnoe sWitty skeg are placed as near as possible to that position normally occupied by a full fin, so as to use to advantage the energy of the garboard stream while at the same time counterbalancing the tendency which most hulls have to drive along the curve of the neutral or Welch axis of the heeled sections, A similar system was in fact used almost universally in the old long skeg Braine yachts to such effect that this not only cancelled out the natural unbalance of the hull, to, ODEL MAKER DYNAMO § ERVICE 1 portance. To achieve maximum effect the fin and 140 difficult to trim in gusty weather, since which I have always given particular attention to this point. The mast position must also have some influence as the further forward this is, the more the hull will tend to feather into the wind behind the thrust point. Fourthly, aerodynamic balance of the sailplan which, while it can never be completely balanced in itself, can be improved by using a fairly large foresail. That these measures have largely been effective can best be judged by comparing the mast position as shown on the plan, with that of other “M” class yachts. In general the sailplan must be moved forward to counter the amount of unbalance of a hull—a poor compromise which shows up badly in a variable wind. With Dynamo I determined that the lead should be given something like the correct amount of advance necessary in order to balance the weight of the vane gear aft. Taking the weight of an “M” vane as 6 oz. or .375 lb., and the distance to the centre of hull balance as approx, 24 in. means that the 15.5 lb. of lead in the keel must have an advance of 0.58 in. (0.375 x 24=0.58 x 15.5). This is, of course, only true providing that the other hull weights balance each other out around the C. of B., an assumption which has been found to be reasonable in practice. The lead as drawn balances out at .57 before the C. of B. which is quite near enough, for although it is well known that a similar amount | A NEW MARBLEHEAD BY THE S. WITTY EMPHASIS DYNAMIC WITH ON BALANCE of advance is necessary for correct trim fore and aft, seldom does one see this achieved in published designs with the result that most models do seem to sit a little by the stern. The sail plan as drawn is quite low compared with some other new designs, but is more versatile and robust as a result. The foresail has been given a straight edge to the leach, thus allowing for the elimination of the battens altogether, which, being limited to a length of not more than two inches, probably cause more turbulence than flow promotion. An advantage of this is that the selvedge of the Terylene can be used to good effect on the leach, thus avoiding the spoiling caused by the lip of the turn-over, the strong multi-weave also helping to prevent angular distortion of the plastic, which is very sensitive to a diagonal pull, As the efficiency of both fore and mainsail is to a large extent dependent on the speed of the airflow at this point any improvement which can be gained is not to be sneezed at. As the mainsail is of moderate aspect ratio, and since the height of the fore triangle is limited to four-fifths of the hoist, the height of the spinnaker is rather less than usual This is all to the good because the long narrow spinnakers often seen do not fill too well in light weather, due to the accumulative weight of the cloth, and are difficult to control when there is any weight in the wind. On the whole I think that Dynamo will prove a little faster to windward than Hornet, particularly in one of the larger ponds, while retaining a very fair chance of success on the run. 141 AN a and in the author’s opinion is the main reason for the apparent lack of balance in yachts having a wide stern. The very first boat built to one of my designs (a 14-in. beam 10R) had this very fault with the result that she was very Dunes en but also the powerful effect of the very long foot of the mainsails which were used then. The small relatively high aspect ratio skeg and rudder used on Dynamo achieves a similar though less harsh effect without the drag caused by the extra root interference, skin friction, etc., by induced rather than forced flow, as is the case with a long skeg. The difference between the old and the new systems can be likened to that between the ancient Archimedes screw and a modern marine propeller which has more space between blades than actual blade area Thirdly, aerodynamic balance of the above water hull which means simply the prevention of any appreciable difference between the centre of air pressure heeled and upright. This is mainly a question of keeping the width of the transom down to moderate proportions, 1958 ——— MARCH, MARCH, 1958 CHINA BOY Part Three of D. A. Macdonald’s Sharpie Marblehead — finishing off the basic hull. Covering the bottom When all is ready tee markings will be very necessary later. The topsides As the topsides of the hull are flared out, the side faces of both inwale and chine strakes will have to be bevelled off to the correct angle. This. work is a little more exacting than the previous bevelling operations as the moulds are cut away at the sides and give no guide as to the angle of bevel. However, the spokeshave can be used (with care in holding it at the correct angle), to remove most of the surplus wood, the finishing off being done with sandpaper 9n Full-size plans for this first-class racing or radio yacht are available from Model Maker Plans Service, price 10/6 post free. for the bottom covering, a template should be made up from stiff paper. (Brown wrapping paper is suitable). This should be pinned to the framework, marked, and cut to allow a small overlap (4 in. to 3/!6in.) all round. From the pattern, the two pieces of 1/16 in. plywood are cut out, trimmed as necessary for an exact fit at the fin and skeg, with a small overlap elsewhere. Pin the sheet temporarily in position on one side and mark a line round it 3/16 in. from the outer edge of the chine and a similar line +in. in from the centreline of the keelson, $in. in from the joint with the fin and skeg and +in. in from the outer faces of the transoms. Prick starting holes for the copper pins at 1 in. intervals all round the pencil lines, and for a couple of additional pins at the ends. Apply glue to the keelson, transoms and chine strakes on one side of the hull, but do not let any glue get on to the moulds. If in doubt apply candle grease or wax to these to prevent them sticking to the plywood. Now apply hardener to the appropriate piece of plywood and pin this to the keelson and chine strake near the centre section and, by temporary pins only, to both transoms. Now start to pin down, working from the centre forwards and backwards in turn, using every third pin position only. Then repeat, fitting pins in the remaining holes. This work must be done quickly as the glue begins to set fairly soon, especially in a warm room. A helper is worth having, in order to get the pinning operation moving quickly, and it would be a good idea to do the work in as cool a place as possible, bringing the hull back into a warm place afterwards for drying. Wash off all surplus glue from the hull with a brush dipped in hardener. When the first bottom piece is dry, trim off the edge on the keelson so that the other bottom piece may be butted over it. and fit the other bottom piece in the same way. When this is dry, trim off the overlap on the keelson. Remove the temporary screws holding the chine strake to the trim off the surplus plywood on the plywood edges can be done plane, set “fine”, finishing off position of the section stations (i.e. the correct faces of the moulds) on the deck side of the inwale, These moulds (1 to 7) and both sides. Trimming with the small block with the sandpaper block. Inwales The inwales may now be fitted. These are screwed and glued into the transoms, the slots in which will need to be chamfered slightly to the curvature of the inwale line. Their positions on the moulds 1-7 are indicated by the deckline marks, and they may be held temporarily to these positions by pins driven through the inwales diagonally from the deck-face into the mould. (These pins will have to be removed later, so do not drive them right in!). Mark the a block long enough to cover both inwale and chine at the same time. Again, care is needed to avoid rounding off either the chine or the inwale and so leaving a gap when the topsides are fitted. The transoms will be bevelled off slightly in the fore-and-aft direction in this sanding process. A ruler laid across from chine to inwale at points along the hull will check that the bevel angles are correct. Next make a paper pattern for the topsides, again allowing a margin for trimming, and cut the two pieces of ply- wood. These are marked for a line of pins }in. from the deck and chine lines, and}in. in from the ends. Pin starting holes are again spaced 1 in. apart (except at the ends, and the pinning and glueing operations are carried out in the same way as for the bottom pieces. Remoyal from the jig When the topsides are dry, trim off all the surplus plywood at the chine and at the ends. The shell can now be removed from the jig. To do this, unscrew the transom securing fillets from the building board. The hull is now free and can be lifted off the moulds. If it has stuck anywhere (due to stray glue spots), the building board should be supported at both ends, with the hull hanging downwards; a long block of wood is placed against the inside of the keelson and tapped gently with a hammer until the hull is released, If the boat has been built on the Lancet system, the slots for fin and skeg should now be cleared out, removing the encroaching plywood with a sharp chisel and finishing off with a file or rasp and sandpaper. Now temporary deck beams are fitted in positions next to the location of the keelson posts and chocks added to these beams to hold the posts central. Glue is now applied generously to the inside of the fin slot; the fin is treated with hardener, and then pushed into place, locating the posts in the chocks on the temporary beams. G-cramps or tool cramps may be used to apply pressure to the keelson at the joint. The skeg is next fitted into its slot making sure that it is line with the fin. This can be ensured by holding fin and skeg together between two long blocks of stripwood while the glued joints are drying. When the glue is dry, and the temporary fastenings for the keelson posts removed, the hull is now in the same state as if it had been built by the alternative method. The rest of the work is now common to both cases.-So proceed to trim off the surplus topside plywood, flush with the inwales. If it is desired to trim. off surplus wood from the inside of the keelson, this can be done at this stage. A useful saving in weight can be achieved in this way. 143 mi Se ase Le le RS WODEL MAKER} Garboard fairing To conform with the MYA rules for the “M” class, fairing has to be added in the garboards to produce a curvature of a minimum radius of 1 in. at or near the midships section. This fairing can be made from a block 13 in. x 14 in. x 3 in. on each side. Obechi or even fairly hard balsa can be used. Place the block flat on the side of the fin and offer it up to the underside of the hull. With a compass, mark off the curvature of the hull on the side face of the block, and the rise of the floors on the ends. The top edge of the block may then be shaped up with a spokeshave to fit snugly to the undersides of the hull. Now round off the lower edge of the block so that it tapers away to about jin. at the ends in a smooth curve. When both blocks have been shaped in this way, they are glued and cramped in place. When dry they are sanded down, using a 2 in. diameter round tube as a sandpaper block to ensure the correct curvature amidships. This may seem a dreadful waste of time and effort, and the fairings are neither useful nor beautiful; but they must be there to satisfy a rule which the M.Y.A. does not intend to change—so don’t blame me! If, of course, the yacht is not for racing under M.Y.A. class rules, the fairing can with advantage be omitted, as it detracts from the performance. Deck beams, etc. From the drawing, measure off the width at the deckline at each of the stations 1 to 7. Starting at No. 4 and working outwards, fit temporary tie-pieces of thin stripwood across the hull at the section stations (marked as you will remember on the inwales), so that the width is held correct at all these points The actual deck beams may now be tailored to fit the hull. Make a template of deck beam curvature from the specimen deck beam in the plan; this template gives the curvature for all deck beams. Set off along a straight line drawn on the wood the width of the deck beam between inwales. Draw the curvature with the aid of the template. Mark out the ? in. square notches for the inwales, allow }in. below the inwales, and complete by marking out the curved underside, to give deck beam shape resembling the specimen shown. Cut out the beam with the fretsaw and offer it to the ‘hull. You will find that it will require some trimming off due to the curvature of the deckline, and the “lugs” which go under the deck beam will have to be trimmed and bevelled by “cut and-try” methods until the beam fits snugly in the correct place. Make all the deck beams you require in this way and fit little recessed platforms to those which support the horses, as shown on the plan. Before finally fixing the deck beams it is advisable to fit the two “floors” which strengthen the midships part of the hull against the stresses imposed by the lead keel. The pattern for these floors may be taken from the cross section shown on the plan. Cut slightly over- size and trim as necessary for a snug fit up against the keelson posts. These floors can be of obechi, and lightened if desired by cutting or drilling out wood from the centre. They are glued in position in the hull and also glued and screwed to the keelson posts. Note the cutaway tips on these floors to allow a drainage path along the keelson. Platforms of thin wood can be laid across the boat from chine strake to chine strake to carry radio equipment in the = desired positions. These platforms can be cut and 144 prepared at this stage, but must not be finally fitted until after the inside of the hull has been varnished. The deck beams are held in position by glue and by screws driven from the top of the inwale. These screws should be well countersunk. Carlings may be fitted between deck beams to form hatchways. The runners between end beams and the transoms can be prepared, and the notches cut to receive them, but they should not be fitted until after the bow and stern blocks have been attached. Bow and stern blocks These consist each of three pieces of wood lamin- ated vertically. The centre lamination can be of mahogany if desired, and this would be a special advantage in the case of the bow block which has to stand up to collisions. Otherwise, obechi should be used. Mark out the outline of the blocks from the profile plan and cut out the three pieces for each block. The laminations are glued together and clamped while drying in a vice of G-cramp. When dry, level off the face of the block which joins the transom. Mark the shape of the transom end on the face of the block, and also mark the shape of the deckline on the top of the block. Use these two lines to guide you in removing most of the surplus wood, with the aid of chisel and spokeshave. The blocks are then glued to the transoms, and further secured, each by a large screw from the inside of the transom. Apply glue generously to these joints and wash off the surplus squeezed out when the screws are drawn up tight. When the glue is dry, the blocks are shaped up to the contours of the hull. The cabinet rasp will be found very useful for the rough part of the work, the finishing stages being done with a sandpaper block. At this time the tops of the inwales, and of the blocks can be planed and sanded down to follow the curvature of the deck beams. Rudder tube To prepare the housing for the rudder tube, start by cutting a “V” groove down the trailing edge of the skeg and round the groove off with a round file or sandpaper wrapped round a tin. dowel. Using the carpenter’s brace and 5/16in. twist drill, drill out the gap between the skeg and the sternmost piece of the fin centre layer. When this is done, the 5/16 in. O/D tube should fit snugly into the rear edge of the skeg and through the hole in the keelson. The runner between mould 7 and AT should be drilled in the correct postion to receive the rudder tube and a trial fit made with the runner in place, to ensure that everything lines up correctly. Now mark off on the rudder tube a distance equal to the length of the skeg, and cut away the tube as shown in Fig. VI so that only half remains over the distance. Drill and countersink the fixing screw holes as shown in the drawing. Now apply glue liberally to the hole in the keelson and to the aft edge of the skeg. Apply hardener to the tube and fix it in position by screwing it to the skeg. The runner between station 7 and AT is now glued and screwed in place, sealed with glue to the top of the rudder tube. If some packing is necessary where the tube passes through the keelson, “load” some glue with fine wood dust to make a thick paste. Use this as a filler and apply some hardener to the filling when it is in place. When all glue is dry, the rudder tube may now be filed down to conform with the lines of skeg and hull. The bow runner (from station 1 to FT) may now be fitted. (To be continued) ‘i MODER MAKER) /| RADIO FOR YACHTS 2 W/B SHEET CONTROL THE EASY WAY Vic Smeed discusses two simple, light, and inexpensive vane/sheet control systems to fit any size yacht TATEMENTS such as that made by our good friend D, A. Macdonald in his China Boy introduction (“Fortunately it is not my present task to devise a radio control system … ) bother us. They suggest a snag to surmount or something difficult to be done—it has been said that 90 per cent. of invention is the realisation that a question exists—and they slip our mental processes out of a comfortable neutral and accelerate us away on all sorts of weight of only, say, a pound and a half to two Naturally, in reducing weight and pounds. expense, some small limitations must creep in, but, as will be shown, these appear quite acceptable, Anyone who is interested at all in radio control will have some idea of the pulse system. In this the single-channel transmitter emits a continual pulsed note and the receiver relay vibrates to it, making no electrical contacts. The operator has two buttons, one of improbable routes to add the most practical 10 per cent. to complete a workable notion. A mental gear-change woke us one night at 1 a.m. and the following thoughts had to run their course before we could drop off again. Mr. Macdonald suggests that the only way which cuts the signal off completely and enables the relay to make one contact, and the other cuts out the pulsing so that a steady signal is sent, causing the relay to make on the opposite contact. The pulsing can be simply produced either electronically or mechanically, the main point being that it provides two “switches” in the model. Let’s start with the sheets. We wire into one side of the relay a small electric motor and battery, and drive via small gears a crank which rocks a vertical lever (Fig. 1) backwards and forwards. The gear reduction determines the time for the lever to complete one cycle— about 6 to 8 seconds would seem reasonable. The sheets are led through pulleys (or tackles if the lever movement is insufficient for full sheet travel) and attached to the lever, the main sheet at the top and the jib lower down at a point which provides a_ proportional amount of travel, having in mind the fact that the jib clew travels through a smaller arc than the main. Now when we press the appropriate button the sails go through a cycle of being sheeted hard down, eased right off, and back home again, all in 6 to 8 seconds, and we can stop them at any point by taking our finger off the button. Snag—to ease off when on the homeward part of the cycle will mean completing a half of the round trip, say 3 seconds, to sail a R/C yacht efficiently is to have control of both sheets and vane gear, and we agree. Such control, however, seems at first glance to call for multi-channel (and therefore heavy and expensive) equipment. However, it appears upon examination that it can be done with quite simple gear, and for an all-up equipment CONTACTS i] i i CAM age a ESCAPEMENT ROTOR a : Hy | 148 MARCH, and it would be desirable to remember which way the sails would move next. This can be overcome by fitting an escapement in the circuit (Fig. 2) so that rotation of selected at will. With a two pawl rotor on the escapement, the normal position is neutral, and a signal moves the Release of signal allows the rotor to move a further quarter turn to the second neutral, and another moves it to the second “action” point. By providing a cam with two contacts at the end of the rotor shaft, we can wire the motor to rotate in either direc- tion at will, if necessary by skipping the inter- mediary contact by a momentary signal. Still to remember where the sails will be driving direct on to the rubber would give a controllable speed for fine adjustment. The vane arm would be fixed to this disc, which would rotate on the vane body. The disc would need a light spring beneath its retaining nut to ensure that it gripped the vane body sufficiently to prevent slip, while remaining capable of being turned by the motor. As in a normal vane, balance would be desirable, and could be achieved by counterweighting without difficulty. The weight of the unit should not be very different from a conventional gear, and tiller linkage ratio, etc., can be variable in the usual way. Optional direction of rotation would be achieved via an escapement (and dial transmitter switch) in just the same way as suggested for the sheets. Problems of visibility and operational “touch” would be no different from the most elaborate set-up, but weight and expense would be considerably reduced. EACH SIDE =e bike, Res HT OR BYPASS PULSER To get an idea of the last two, let us consider practical needs, First, cost. Transmitter and receiver—any commercial set-up, say £11. Built yourself, maybe £4. Pulse box, purchased, £3; home-built, less than £1. Dial switches, home-built, pence. Two Rising clockwork escapements, £3 5s. Od.; home-made from clockwork toys, say 15s. Two TG 18 motors, just over £1, or you can find cheaper ones, Say £20 with all-commercial gear, possibly only £8 or so if you do it yourself. Model weights— receiver and batteries, 14 oz. Two escapements, two motors, and required batteries, 14 oz. Wiring, sheet gear, four or five ounces. You can increase battery sizes if you wish, but adequate sizes for some hours’ operation have been allowed for. * k * * When discussing the above with A. C. Armstrong, the following system came to light, Basically, it is a development of the multicontrols from single channel published in our May, 1957, issue, but uses an electronic pulse box for the transmitter and a_ simplified actuator circuit; developed and tested with steering and engine control in a boat, it is quite adaptable to vane and sheet control. SPRING RUBBER ‘TYRE’ (OR GEAR) MOTOR MAIN PIVOT 149 é got moving? Not necessarily—fit a simple dial switch on the transmitter (Fig. 3) which will always correspond with the escapement and which can be coloured to enable a glance to sort out where you are. It would probably be necessary, by the way, to fit a delay condenser to each side of the relay, to avoid inadvertent triggering of the escapement. Nothing very new in all this so far, and still we have the vane to worry about. Well now, we don’t need anything very elaborate for ‘the vane—no self-tacking or swivelling body mechanisms or locks, etc., because the thing is going to be under our control at all times. Fig 4 suggests what seems a suitable gadget; the motor (TG 18 or similar) is mounted on what would normally be called the vane body, and drives, either by gears or friction, the vane arm in a circle. Using a rubber-tyred disc of 24 to 3in. diameter with the motor spindle CONTACTS CONTACTS . tie rotor a quarter turn. HOLD KNOB FORE OR AFT FOR TIME REQUIRED TO OBTAIN DESIRED TRIM Cou the sheet motor can be 1958 mi HT + 45 VOLTS SHEET OUT < PAKEYSWITCH servo; relay 2 normally lies in the pulsed position, i.e. out. With a 50/50 pulse the vane servo will merely dither with the continual current reversal, but will not turn the vane. Any tendency to “creep” is killed by adjustment of the P3 potentiometer on the pulse box. Using key NE CLOCKWISE YA Vane ANTICLOCKWISE PO. KEY 50: RRS ] switch will alter the ratio of When key switch 2 is used a steady full or no signal results and relay 2 in the receiver pulls in, switching out the vane servo and switching in the sheet motor. Whichever side the switch is pressed, the sheet motor will move the sheet arm accordingly, and when the key is returned to neutral the sheet arm. will. stop aSWITCH * in that position. The pulse box circuit (Fig. 5) gives the basic idea of the set-up. With both key switches in neutral (i.e. centred) the box gives out a 50/50 pulse. This is adjusted by potentiometer P3, which is provided with a knob on the face of the control box. Moving the key switch 1 to the left selects the extreme end of pot P3 and gives a 95/5 pulse, this ratio being adjusted by Pl. Moving the switch to the right gives a 5/95 pulse from the other end of P3, the ratio adjustment being P2. This is much faster and easier than turning the knob of P3 from one extreme to reversion to 50/50 pulsing automatic. 1 current passing backwards and forwards in the vane servo, the servo rotating in the direction of the greater ratio. The vane can thus be moved to any position and held. the other, and is, of course, P.O. key switch 2 selects either full off or full on, the central position allowing pulses of whatever ratio key switch 1 decides. The controller’s mechanism, then, simply consists of a box attached to the transmitter with the one potentiometer knob (for pondside adjustment at the outset) and two key switches suitably marked. For large waters a desirable addition would be two repeater indicators, synchronised to the model, to show the actual positions of the controls at any time, but this is not absolutely essential and the basic pulse box can be built for a total cost of about 45/-. Any single-channel transmitter can be used. The gear in the yacht will consist of a receiver (the Armstrong circuits are based on. the Hill 2-valve receiver with an additional valve for pulse discrimination—see May, 1957, MopeL MaKER) plus two relays of about 5,000 ohms ; the Manning Carr type is suitable. Relay 1 follows the pulse ratio and so. continually reverses the current through the vane 150 It would possibly be neces- sary to provide stops for the extreme positions of the sheet arm to prevent the servo crank from completing a full revolution and thus creating the possibility of control reversal. Probably a worm-driven crank would also be an improvement, and with a worm there should be no difficulty in respect of power available to sheet in even A class sails in a blow. Cost of the yacht gear—well, you can buy a kit for a Hill receiver for 30/-, plus valves, plus two relays and two servo motors—say about £6. Weight is no problem, since the system is light enough to use in even a smallish aircraft model. A pound-and-a-half covers it easily, including all batteries, making it entirely feasible for even the 36R class. Batteries allowed for would cover a full afternoon’s continual sailing, but in any event the only ones with any serious drain are those for the servos, and there would be little objection to changing these midway through anyway, Well, there it is. Seems workable to us, though radio boffins may be horrified, If we’re wrong somewhere, or someone has a better idea, let’s hear about it, as only by publicising constructive thought on the subject will the “ultimate” system evolve, (ric 6| RELAY 2. RELAY /. oe oe VANE SERVO oe ne plan STEADY SHEET SERVO s ‘i MARCH, The Little Portugal Cup (A-Class) When the late Mr. J. P. de Freitas of Portugal presented the “Little Portugal” Cup to the Model Yachting Association, about eighteen months ago, he made certain stipulations as to its purpose and uses, but gave the M.Y.A. entire power to vary these conditions if it was found desirable. A number of suggestions were made at the Council Meeting where the matter was discussed, and to me, at all events, it was not altogether clear what conditions were finally adopted. Hence in my “Talk” that appeared in the August, 1956, issue of this magazine, I included a suggestion made by one of our officers that the venue for these cup races should not be Fleetwood or Gosport as these waters are used for the British A-Class Championship and International “Y.M.” Cup events. I must apologise as this suggestion was not officially adopted. However, to make matters entirely clear, | now have pleasure in reproducing the official conditions which govern the “Little Portugal’ Cup:— 1. The Cup is to be a perpetual trophy known as the “Little Portugal’ Cup. 2. The Cup is the property of the Model Yachting 3. 4. 5. 6. Association. The Cup is open to competition amongst yachts of the International A-Class. Entry is limited to skippers who have never before won this Cup, the British Open Championship (A-Class) Cup, or the “Yachting Monthly” Cup. The venue of the races, and any other conditions of entry, shall be decided from time time to time, by the governing body of the M.Y.A., The governing body of the M.Y.A. may change any of these conditions should fulfilment be found impossible. N.B.—Condition No. 4 was subseauently extended to include mates as well as skippers. It will also be noted that there is no bar against yachts that have won the Cups detailed, provided they are being handled by a skipper and mate, both of whom are eligible to sail for this Cup under Condition 4. There is, likewise, nothing to prevent an owner who has won the Cup previously, entering again with the same or another yacht, provided she is sailed by a crew who are eligible to compete under Condition 4. M.Y.A. News The sad death of our old friend, Mark Fairbrother, left the M.Y.A. News without an Editor, but Mr. H. E. Andrews (9a Spencer Road, Boscombe, Bournemouth, Hants.) has now kindly undertaken the job. He states that just as soon as Club Secretaries and others furnish him with the necessary material, he hopes to produce his first number. Subscriptions and accounts should, as heretofore, be sent to Mr. J. G. Meir, 129 Ladypool Road, Birmingham. 1958 ~ UCKER’S DEVOTED THIS MAINLY TOPICAL MONTH TALKS TO M.Y.A. NEWS Ne sf sailed in almost every country that is a member of the I.M.Y.R.U. The main merit of this class is that it produces a model of convenient size and weight for travelling. It has the demerit of all classes embodying an L.O.A. measurement in that it produces boats without overhangs. Also the rule precludes the use of an unfilled (or unpadded) garboard angle. Whilst this may be a desirable restriction on round-bottomed yachts, the filled garboard is bad technique and entirely unsuitable on sharpies. All suggestions that the rule should be amended in this respect for sharpies have hitherto fallen on deaf ears as far as the American originators of the class are concerned. International contests have recently taken place between French and Italian model yachtsmen, the class of yacht used being the French National 1-Metre. This is a restricted class, of which the main features are;—L.O.A. 1.00 metre. S.A. 40 sq. decimetres. The maximum hoist allowed for sail is 1.60 M., and jib hoist is restricted to 4/5 of maximum hoist. The method of computing S.A. is unusual. Mainsail area is taken as 4 (luff to underside of headboard x foot), while headsail area is taken as 85 per cent. of + (luff x foot). The French National Association, seconded by the Italian, have now suggested the adoption of this 1-m. class as yet another I.M.Y.R.U. Class. The suggestion has not received the approval of the M.Y.A. as it is felt that we already have enough I.M.Y.R.U. classes, and this in no way prevents the French and Italian Associations from using the class for international competition between themselves. While this matter was being discussed at the first M.Y.A. Council Meeting of 1958, reference was made to the Belgian National 1-M. Class, as being a far better class than either the French 1-M. referred to above or the M-Class. As a matter of interest, I quote the formula for the Belgian Class which is:— L.W.L. (in cm.) + v S.A. = 1 metre (or 100 units) L.W.L. measured in fresh water. S.A. measured as per I.Y.R.U. (taking 85 p.c. of fore triangle) in square c.m. There are a number of restrictions, the most important being on draught, which must not exceed 16 p.c. of L.W.L. plus 8 c.m. Any excess is multiplied by five and added to the rating. The yachts produced by this rule are about the same size as the M-Class with overhangs added and a shade more S.A. In fact they are much like a 5-rater would be, and very nice little craft. I.M.Y.R.U. Recognised Classes At present, the I.M.Y.R.U. recognises three classes of yachts—the A-Class, the I.Y.R.U. 6-m, (1} ins. = 1ft.), and the M-Class. Of these, the 6-m has waned in popularity in England, though it is still extensively used in Scotland. As far as I know, it has never enjoyed any real popularity outside Great Britain, and it would make little or no difference if M.Y.A. National Championships The venues and dates for most of these events have now been fixed as follows:— 36 in. Restricted Class: Clapham, 3rd and 4th May 10-Rater: Birkenhead, 24th-26th May. 6-Metres: Bournville, 31st May and Ist June. A-Class: Gosport, 3rd-10th August. it was removed from the list of International classes. The M Class, on the other hand, is probably the most numerous class of model in the world, and is M-Class: 154 To be announced later.
