- Description of contents
He ae ; ae a ee eee ae ie aving discussed the possibilities (and drawbacks) of producing a scale-type dinghy last time, it seems a natural progression to pass on to scale-type displacement craft, say up to fivesix tonners. Many owners of these like the idea of a model of their craft, perhaps especially a working model, which is often a reasonable proposition if the prototype has auxiliary power. Under sail such models are still likely to be tender, for the reasons discussed last month, and if sailed in light winds which are quite likely to die away suddenly, the ability to switch on the motor and retrieve the model under its own power is useful. In fact auxiliary sailing craft models seem to be operated under power much more fre- quently than under sail, probably because they are much easier to handle and can be run in a wider range of weather conditions. Without sails (or with furled sails} there are no stability problems and although they will suffer from slightly greater leeway than a ‘straight’ power boat the difference is virtually insignificant. The weight of the mast(s), sails and related gear will want to make them roll more, but offsetting this will be a fin and a certain amount of ballast, so that the total effect is likely to be a vessel which pitches and rolls more than a normal power boat but within well-defined limits. Because of the fin they may be directionally more stable but not necessarily so, as many straight-running enthusiasts who have added fins have discovered. Early screws The Hegi tnga kit has been around for many years but it is a very good example of a motor sailor and is possibly the only one of its kind currently available in kit form. The model is 44in. long and can be constructed with a removeable mast to ease transportation. When screws were first applied to sailing craft around 150 years ago, they tended to be multi-bladed, or large diameter and area and fine pitch. They were seen as a means of propelling a sailing vessel in calm conditions, the sails being used alone all the time there was wind; even the ability to power nearly all the way into ports or up estuaries, against tides etc. was of very secondary importance. Because engines were very inefficient an enormous amount of fuel i would have been needed for long periods under power and with the weight of the steam plant the reduction in cargo capacity would have rendered the whole exercise uneconomic. However, the presence of a huge screw under water had the effect of considerably reducing sailing performance and many experiments were made in attempts to reduce its drag. The most successful, if cumbersome, was to mount the screw in a frame sliding in vertical channels so that for sailing the whole lot could be winched up above water. In calms the propshaft could be barred to a marked position and the frame slid down with a dog-drive engaging automatically. No doubt there was time to do this while steam was raised in the simple pot or haystack boiler. Some of the early boilers even used salt water, but once the wind piped up again and the boiler had cooled there was no doubt an opportunity to clean the salt out. Even with improving engines this type of lifting propeller continued in use for at least 40 years, and it was not until increasing passenger trade and reduced cargo weight (plus, of course, major steps in steam raising and engine and propeller efficiency) ushered in the sail-assisted steamship rather than the steam-assisted sailing ship that a permanently submerged and fixed pitch 96 screw became the norm. Propeller drag still exercises the minds of designers of present-day auxiliary sailing craft, even though the props used are tiny by comparison. Free-wheeling props were tried but feathering or folding ones are now most commonly used on yachts whose primary purpose is high performance under sail. For weekend cruisers where absolute speed under sail is less important, the drag of a fixed two-blade prop, perhaps only of 9in. diameter on a 30ft. hull, is considered not unacceptable compared with the cost and possible maintenance requirements of a folder or featherer. In many cases the auxiliary power is in any event provided by a portable out- board motor, either hung on the transom or through a well, which can be tilted or raised to lift the prop clear of the water. Drag reduction . Any of these drag-reducing methods could be applied to a model, but few modellers would go to the trouble. The chap who will use the model as a form of power boat gains no advantage (except possibly true scale detail) and those who wish to operate under sail will usually accept the drag rather than face the difficulty and expense of reducing much of a problem: the blades would assume the working position, by thrust, as soon as rotation commenced, just as with a folding prop rubber model aircraft, but they would have to remain very free in order to fold back and the saving of drag would be slight. A feathering or tilting prop would need an extra servo to operate it. Many modern small cruisers with an inboard engine have the engine, or at least the prop-shaft, offset from the centre-line. This may be to avoid structural complications, to prevent flow break-up round the fin and/or rudder, or simply to allow the prop to function in relatively undisturbed water. Any of these factors could arise with a model, and although asymmetric thrust will cause a very gentle turn, only a tiny amount of rudder should straighten it and there are many advantages in fitting the shaft ¥,in. or so off centre, mostly, in models, structural. Once again, the boat used as a power-boat-with-mast is in a different category, since a central prop would perhaps.make such a model easier to put round a steering course. The exception, naturally, is if the model is based on a twin-finned prototype. There are several such cruiser designs, mainly intended for use on moorings which dry out Model Boats when as the tide falls the boat will bump gently on specifically reinforced areas and end up sitting upright on its fins. Props on these are well protected and the best place for them, structurally and dynamically, is on the centre line. fairly tender and probably sluggish. At five Cruising yachts are much finer-lined and do not cater for cargo, but they do allow for stores and crew/passengers. On a 30-36 footer this might be as much as 1,000Ib, (six people plus food and water etc. for a week) which sounds useful until you work out that Fins Older readers may remember the two _ twin-finned ten-raters with which John experimenting around 1960. These showed that performance need not be drastically diminished by using two splayed Lewis Cruising yachts was fins, but in those days, when ballast conventionally fitted in the shape of the fin, getting enough weight in the slim, narrow fins entailed using cast iron fins. It would be interesting to see how the boats would perform with twin modern bulb keels, where the CG would be dropped by three or four inches. Whether single or twin-finned, a scale model of a displacement yacht will need a deeper fin(s) to sail well in average wind conditions with seale sail area. The practical answer is to make the hull and fin to scale but introduce a slot through the fin, into which a sailing fin can be fitted. This would deepen the draught of the boat and could carry the ballast weight required to bring the hull to the scale waterline in the form of a bulb. Displayed on the piano or wherever, the model would be a scale repre- at 1/10 scale (a 36-42in. model) tons (111b) it would be a much better boat, but would still need a couple of inches more draught to be able to compete with the 36R. Note that none of the boats would fit the 36 x 9 = Liin. box of the 36R rule in the conventional manner, though the 30 and 41-footer 1,000]b comes down to just 1]b. This is still a noticeable proportion of total weight, since a cruiser of this size might have an empty weight of 3%, tons, equal to 7.8lb at 1/10 scale. On the other hand, a 3¥, tonner sailed with full canvas in a fresh breeze can be heeled to the gunwale and, from experience, even three crew sitting out on the high side doesn’t seem to reduce the heel noticeably. A typical six-berth cruising yacht could be 30-32ft. overall, with a beam of from 8¥, to 10ft., draught 4-5ft., sail area around 950sq.ft. and a displacement of between 3Y, and seven tons, depending to some extenton whether it is primarily a sailer with a small auxiliary or a 50/50 motor sailer. Comparison with a 36R model and these maxima and minima at 1/10 scale is interesting. A larger and a smaller yacht at different scales are included, see Table 1. Scale fin False fin with tongue thro’ fin would fit in sideways. There have been ex- periments made with models designed to fit the box this way, but they have been unsuccessful on the water. If building a model for the owner of a cruiser, he is probably going to be delighted sentation and the slot would be virtually invisible. The false fin would only be fitted for sailing and even then would be out of sight with the model afloat. This is virtually standard practice for scale sailing models, although there are occasions when a scale model of a cargo- carrying vessel with fairly coarse lines and fair draught might just sail without it. This is because the normal waterline of the hull would be achieved with a full cargoload and we can put weight on the equivalent of the cargo the bottom of the keel. The extreme example is the box-like hull of a Thames barge, where the cargo weight exceeded the empty weight and in light winds a large scale model (‘4in. scale, or 1/24) can have reasonable stability with ballast laid on the flat floor of the hull. Even so, a detachable fin keel would provide better sailing performance (see Celia Jane notes, page 689 of last December’s issue). The seven-ton 32-footer used as a basis actually has a draught of 4ft. (4.8in.) but other, lighter craft can be found with 6.6in. scale draught. The 41-footer is at 1/14 scale and is a French design with a 3¥, ton bulb keel which at this scale works out at about 2.861b, and the 27-footer is a popular cruiser at 1/9 scale. Seven tons is actually exceptionally heavy for a 32ft. vessel of this type, and if we take five tons as being more typical we could have an 111b model with 6.6in. draught. The deepest proportionate draught we have noticed comes on a 21ft. drop-keel design, which at 1/7 scale would give a 36 x 12in. if the model sails in near-calm conditions and would not think of trying to sail it in a> blow. A modeller might expect more, and the examples quoted give some indication of the chances of success. The simplest way of using an auxiliary motor is to settle for a single-speed switch on/off installation and to fit a change-over microswitch where it can just be operated by the rudder tiller when full rudder and full trim are applied. If the trim control is not right over full rudder can be used without hull with a draught of 9′,in. Sail area at an estimate would be about 440sq.in. and dis- placement at a guess around 9-10]b. If looking for a scale prototype this yacht, the Westerly Jouster, seems well worth investigating, since it could be true to scale and sail well. Looking at the table it can be seen that when all vessels are reduced to a similar overall length, all of them exceed the beam of a 36R racing model and all but one have Offset prop greater sail area. However, even the best of them has considerably less draught and, if we except the seven-tonner, they are all below the 36R displacement. If we allow 3’4]b for hull, rig etc., we get the ‘probable lead’ line and we can probably knock another */,lb off each for radio. This, without a false keel, virtually eliminates all but the 32-footer, and even with an extension on the Twin fins fin only the 27ft. boat would be able to cope with a reasonable breeze. The seven-tonner would sail even with its true scale draught of 4.8in. because of the amount oflead and the beam, but it would be February 1985 Jouster type drop keel fear of switching the motor on or off, but when switching is required the trim is pushed hard over and application of full rudder will then trigger the switch. A simpler switch can be used if a third channel and servo are available, or if a deluxe arrangement is required a stop/ forward/reverse variable speed controller can be operated by the third channel. In either case rudder control would be normal, and the motor would only be used with the sail furled or as a retrieval system if the model was under sail and the wind died. 97 Not the most attractive looking hull shape, but she appears to do the job. Beam overall fs 18.5in. boat eliminated the diving characteristic and performed well. However, I felt it was desirable to evolvea design specifically based on the requirements for ‘Round the Buoys’ racing rather than adaptations of vane sailed boats. Concept A major consideration for the new boat design was ease of handling, i.e., it must have no vices, and be consistently easy to sail across the full range of wind and water conditions. Under radio, experience has Breakaway A new Marblehead design by Andy McCulluch design for radio, is the question of making the boat easy to sail. Displacement Past racing experience has indicated that there is no such thing as an optimum displacement for all-weather conditions. In consequence IJ elected to go for a mid-range weight, in the order of 14¥,-15lbs. Distribution of Buoyancy It has been established that it is advantageous to spread buoyancy throughout the entire length of the hull, as this reduces the tendency to ‘pitch’. With fine bow sections this caused a design problem. This was overcome by flattening the rocker in the midsections, in order to push buoyancy into the ends of the shell. This has largely overcome any tendency to pitch in a chop. Wetted Area ~ To dispel any fears people may have about the wetted area with a wide boat, I can assure them that this has been proven not to be a problem, even in light airs. It must be remembered that although the deck beam is To give some insight as to the need for ‘yet another new boat’, I will briefly run through some of the historical reasons which led to this ‘radical’ new re-think of Marblehead SAIL To History design. I began sailing Marbleheads in the mid1970’s when the availability of cheap and reliable equipment opened the door to multi boat model yacht racing. In those days it seemed only sensible to follow in the footsteps of the vane sailors, who had been developing designs for 60 or more years, and were producing undoubtedly fast boats. With this in mind, we readily accepted the shells that were available at the time, which were fitted with radio gear and rushed to the pondside to race. I started with the Stan Witty Skippy which was considered to be a good ‘steady’ boat. During these tentative development days this design served well and provided an ideal platform to work from whilst some of the more basic problems of control were overcome. However, as the science progressed, the quest for faster designs came to the fore, and with a glance back across the water to the vane sailors, I moved on to a Stollery Mad = ee No Males ie a reifiver ET 33 Hatter. This boat was undoubtedly quicker up wind, but suffered badly from nose-diving when pushed hard on a run. This experience led mein the direction of a Mark II Poppycock from the board of Graham Bantock. With its high bow, this 98 Waterline beam is 11.5in. and draft is 14.5in. All photos by the author. llin. wide at the proven that it is not the sensitive, difficult to 18in., the boat is only waterline. more the but tune boats that win events, tolerant designs, even though the sensitive boats may be faster when they are set up Bow Sections As will be seen I have used a high flared correctly, The problem is that there are very few skippers that can make this breed of bow which provides adequate buoyancy to boat go fast all the time. This has led me to stop nose-diving, and a very fine pinched believe that the most important aspect of and concave entry on the waterline to miniModel Boats 8 LUFF POETION ye ALL TAKE Tuse To SAILPLANS, S48 HAST RG MASA, DIME SIONS, a furry CLEW OF WON SUIT JIB SHEETINS MAINS AIL SO 1 #00 MARGLEKEAD SoD ine tas ae ery) Deas T 1k She OISPLACENEN? feour 8 Oboe POINT MAINSALL SHEETING POINT th TOR RUDOEN PHOT ceme nt 112! BUMPER ; BECK BEAM POSITONS LEE shows THUS | eee —— – — ee an __ rs ee| ee po i. ae ee. ~ 5: 28 oe \ | Po t EAD BULB O02 LAS SHOMN! {a § a CO Po aE \ oT en, a | . 2! ~~ MMI369 The full size plan for Breakaway is available fram Model Beats Plans Service, PO Box 35, Wolsey House, Wolsey Road, Heme! Hempstead, Herts, HP2 4SS. Please quote plan number MM1 369; price £3.60 plus 50p post and packing. Plan includes body lines for smooth and hard chine versions plus a reduced sail plan. mise any tendency to ‘slam’ whilst working to windward. This combination has been very successful in practice. Mid Sections Modern radio Marbleheads are sailed very hard, and must be able to withstand slight over-canvassing. We all know this is bad practice, bit in reality, especially witha variable wind speed, most boats are sailed to a point where they become over-powered. What matters then, is that control is maintained even under these conditions. This naturally leads to the question of stability and ability to carry sail area, i-e., the stiffness of the boat. With Breakaway I have carried the deck. and waterlines out much wider than average to counteract this problem and the result is a stiff boat, which tolerates being over-canvassed in the gusts and remains controllable almost regardless of wind strength. February 1985 Aft Sections . The aft sections follow through from the mid-section shape naturally leading to a shallow dish-shape on the transom. I have tried to maintain buoyancy in the aft end, mainly to ensure that when the boat is heeled going to windward, the extra buoyancy aft encourages the bow sections to stay immersed. This I feel is important for windward performance. Conclusions Overall you will see that a wide, powerful boat has emerged, which, in practice has proven to be a good all-round performer. The drawings show both hard chine and round bilge versions, both of which have been sailed successfully in competition. T trust that the boat will give any builders good service, and I wish them every success when racing. The sharp and blunt ends of this unusually shaped boat which dispiaces between 14.5 to 15ibs. 99 earl Sail Measurement for Ms The latest issue of the American Model Yachting Association Quarterly reveals an 85-15 thumbs down to the proposal to adopt a set of M rules different from the rest of the world, which is encouraging, buta 75-30 vote in favour of changing the method of sail measurement. Regrettably, we do not see this publication regularly, and cannot say what the sail measurement system entails, though since it appears to have been adopted for all AMYA classes it can only be something basic, like measuring flat on a table rather than See width. In other words, marked deviation from the norm would have to offer an obvious efficiency bonus. Rather than penalising sail experiments, this could urge them to more research but with an additional parameter. In placing such a restriction we would be reducing the advantage of expensive sails and producing perhaps more even racing. From the average club skipper’s viewpoint that may be no bad thing, and for the expert, well, the best tuned yacht with the best-set sails will still win, so it is not as retrogressive a suggestion as it may at first appear. There is still a basic difficulty, and that is the variation in what are taken for granted as accurate measuring tapes. This caused considerable problems and embarrassment at the last World Championships, where there was almost a centimetre difference between the three tapes used. What was out of rating on one tape was in on another, and it took some time to realise that one or more of the tapes was at fault. Are we trying to be too precise? In a Marblehead luff 1cm is about half per cent, but if half per cent tolerance is allowed the keen lads Roulette, Bob Burton’s fast entry in the A champs (near camera}, an event he had won twice. See Obituary opposite. rigged on the yacht, or possibly how much tension may be applied or similar. What is clear is that this sort of unilateral decision is what makes it necessary to process all the entries in a World Championship, or other international race to ensure that all countries are interpreting the international rules correctly. In turn this is what sparked off the ill-fated M-rule revision three or four years ago, one of the aims of which was to adjust rules in such a way that their method of application was unambiguous. We are clearly still a long way from that desirable state of affairs: most of the solutions put forward have been overly complicated or, if not, have been argued out by people saying “Ah, but what if…” This sai] measurement business raises more queries and seems a bigger stumbling block than any other aspect of any of the class rules. And, no thank you, the answer is not to follow IYRU procedure, which is far too complex. In full-size in. is neither here nor there; but ¥,in. in model sails is significant; it can easily be fiddled by varying tension. The more measurements that require to be taken the greater the chance of error in the average club. It should be possible to evolve something simple? A lot of people seem to think that measuring on a flat table is preferable, so suppose the head eye has a panel pin driven will push it to the limit, just as M hulls are always 504,in. (plus bumper) since ‘in. (i.e. half per cent) is the allowed tolerance on the 50in. nominal hull. In view of the relatively small numbers of people prepared to compete internationally, would it be an answer to have a separate ‘International Standard’ system of through and, say, 1kg (2.2Ib) tension is applied with a cheap spring balance to the measurement? It doesn’t really bother the average club skipper if he is sailing against (on a line bisecting the luff if you want to be fussy) and the clew eye pinned. Luff height area, and since the backbone and finance of the movement is composed of such skippers why should they be bedevilled with tack eye, which is then pinned securely. The balance is then applied to the clew eye and foot length, or the longest length at right-angles to the luff, are then easily measured. Now, anything outside the basic triangle could then be measured and calculated and added to the triangular area, breaking down awkward shapes into rectangles, triangles etc. which is tedious rather than difficult. Or, simpler, the half-height measurement taken (i.e. a right-angled measurement taken at 50 per cent of luff height) sail edge to sail edge, with the rule in contact with the sailcloth all the way (a flexible tape?) and this figure to bea maximum percentage of the longest length at right-angles to the luff. This would mean that a very full-bodied sail would havea slightly smaller chord length thana flat-cut sail, but presumably itis more efficient and the gross power from either sail would thus be more nearly equal. If the luff is cut with a pronounced convex to fit a permanently bent mast, the distance by which it extends forward of the straight luff line will be deducted from the roach someone with three square inches more sail unnecessarily complex rules? Sails measured to international standard could bear a rubber stamp to that effect. In many sports an intending entrant must take out an international competitors’ licence, at some expense, so 1t would not be so difficult to expect a would-be international skipper to cover the cost of a special measuring session where the rules could be as complicated as they want. The matter of sail measurement is certainly the major area of controversy and almost any suggestion put forward can be guaranteed to attract disagreement; despite this, in giving the subject a prod we can confidently anticipate a totally underwhelming response, as usual. Classes Also evident from the AMYA Quarterly is the number of classes recognised in the USA — no fewer than 16. This arises from official sanction being given to a class when someone can produce 20 registrations 100 Model Boats in the potential class. Half of the 16 are commercial kits, representing an approach to model sailing unique in America. Some critics may feel that this is fragmentation of what is already a relatively small sport, but in a country with such vast distances, it is not really surprising that if a particular model proves popular in one small area someone is going to form an association to get some racing going. If 100 registrations are needed for recognition, well, the yachts sail the same and racing is much the same if the class is unofficial; by recognising them when 20 are keen enough to register the AMYA gains another group of members and there is always the chance that the class will catch on over a wider area, even answer, however, is that if 50 ofa design are registered and an affiliated club proposed recognition, Council can move, but they aren’t prepared to initiate something which may not succeed. R. J. Burton _ We regret to report the death in August of Bob Burton at the age of only 60. A member of the Clapham club since before WW2, he had moved to the coast in 1965 and was commodore of the Eastbourne Club; he had also served for a period as MYA Racing Secretary in the 60s. His expertise as a skipper arose from sailing with his father, whose Braine Left: “Guns plus three” and right, ‘A fairly close finish’ at the 575 Chiltern Open meeting at Hinksey Lake, Oxford. Photos M. Boast. He was the instigator of the sailing lake at Bournville and was founder and, for many years, president of the Bournville MYPBC. Although he relinquished the presidency when the park was made over to the local authority, he remained a life member and vice-president of the Club and was a good friend to model yachting. The Mid Thames 575 Open — October 28th — Reported by M. Boast At one stage 23 people had entered for this first ever open 575 event to be staged by the club, but with rain forecast for the day a few people dropped out beforehand and so the field was reduced to 18. It was planned to have 12 heats with each entrant having 6 races; this worked well with the last two races being held in calm but wet conditions, the previous races having had a good breeze, enough to complete two laps of a large course. Of the twelve heats nobody won more than two with seven skippers taking five honours, «55 nationally or, as in the case of EC12, internationally. An example of the old saw “Nothing venture, nothing gain,” perhaps? Apropos of which, it is interesting to see that Bud Salika (who we have met at regattas over here) has launched what is hoped will be the ‘AMYA One-design’ and initial response has been requests for 96 sets of drawings, including several from clubs, plus some enthusiastic letters and one dashinga bit of cold water. Don’t know what the boat is, except that it’s simple and the hull can be built from 80 ‘4*4,36in. lengths of balsa. A smallish, simple onedesign has been suggested to the MYA from time to time, i.e. the MYA Council would choose and promote a suitable design (possibly through a design competition) to attract newcomers, even perhaps seek some sponsorship for a national event. The boats he continued to race with considerable success in 36, M and 10 classes until 1960, when he turned to vane; he won the 1963 and 1969 A Championships with two Highlanders and he had also twice won the 36R Championship. It was always a the best five results of the six races were counted as the contestants total for the day. Many thanks to all who attended and the final results were as follows: pleasure to look at his boats, which were invariably beautifully built and finished, and he was also a designer with an eye for grace as well as performance. Only recently he had ventured into radio and it was clear that his skills would have shortly taken him into the top flight. Our sympathy is extended to his family. Paul Cadbury Less well-known to model yachtsmen generally was Paul Cadbury, of the Cadbury family, who died in October. Next year the open will take place on 22 September pre-entry to M. Boast. For the best in fibreglass hulls and scale drawings \ WE SHARPEST NAME WW ORAFT TOOLS Kingston Mouldings For your next model, why not begin with a top-quality fibreglass boat hull from our range. All our hulls are strongly and accurately moulded, and with each hull we supply a copy of our own detailed draughtsmandrawn plan. We currently produce about 30 different scale hulls of various types, and if you send us 50p in postage stamps, we’ll send you a copy of our latest illustrated cata- C10 CRAFT BLADES Obtainable from most Graphic Art supply shops February 1985 logue and price list by return. Exports are no problem atall, and we’ve sent our hulls to customers in many different countries all over the world. Outside UK send 4 IRC (International Reply Coupons) or £1 or S2 currency note (US, Australian or NZ) and we’ll send you a catalogue by airmail. Kingston Mouldings 411 Ringwood Road, Parkstone, Poole, Dorset BH12 4LX. 101 7 Ht twisting the rudder in situ, a bit risky. but it worked. See Figs. 1 & 2. 5. Carefully cement deck to hull to prevent leaks. . 6, File lip off flange of deck to reduce water drag when heeled. See Figs. 3. 7. Make all parts — mast, booms, sail winch, etc. exactly as instructions; the time to experiment is after you have won your first race! 8. Make sure that the sail winch arm gets a full sweep so that the sails can swing out a full 90° to the boat centreline. 9, Use lead for ballast. Your boat will not be competitive with concrete ballast A flotilla of 575s photographed at last year’s national Championships. 575 Beginners Please Roy Waddington offers advice to new builders of this popular one-design yacht his article is aimed at beginners. Not just beginners at sailing model boats but those who are also beginners at building model boats in general. The 4575 from Lesroa is a beginners boat. This is because it is a quick-build and very complete kit and is comparatively cheap. This is not to say it is a boat which only appeals to beginners and who normally progress to better things. Oh no! Quite the contrary, it is a boat that has a large following of keen and expert skippers who enjoy tight competition in a series of well supported regattas throughout the summer and autumn. It is a boat that gives pleasure to skippers at all levels of expertise, that has characteristics of full size ocean racers (after all it is semi-scale), is tender, gets knocked down if pressed too hard in a blow, rolls down-wind, even broaches-to like a fullsize yacht if not steered carefully before a stiff breeze. Not at all like the model yachts of the established classes which although they may produce a good turn of speed have a performance that is artificially stable compared with a full-size craft. However, to get back to the project in hand, which is, basically, to produce a series of tips for the beginner so that he or she may hopefully avoid some of the elementary as suggested in the instructions. This mistakes which cause much frustration and is the one exception to rule 1. I found lib. 10’40z. (750g) required making an all up weight of 3lbs. 5ez. (1.5kg). 10. Start with ballast enough to float boat level on the waterline. I found that the lead plug in the keel needed to be thicker at the front than at the back to float the boat level even with the receiver in the bows. See Fig. 4. . 11. Set mast up straight, not leaning to left or right or fore or aft. perhaps even the abandonment of a sport which is such good fun, by the less persevering of us. Fig. 3 File off 12. Do not set up standing rigging so tight Rudder wire fouled transom Seal with cement ‘Hull One of the great attractions of the 575 class is that itis a restricted class so all hulls are competitive no matter how old. The make-up of a top class boatis about 8% basic assembly, 2% tuning and 90% the skill of the skipper. This means that to get oneself into the position of winning the odd race or even hanging onto the leaders for a map meansa lot of practice. However, to get started on the right road it is essential that the basic 8% is correct. Without certain basic adjustments being about right the boat will not tack quickly, will not point to windward and will generally Fig. 1 give the impression of not answering the controls. Here then are my humble offerings: 1. Read and follow the instructions in the kit carefully with one exception. 2. Make sure that the rudder is held flat when the halves are cemented together. Polystyrene cement softens the plastic and it may warp if not careful. 3. Set the rudder up carefully so thatitis perfectly in line with the keel when viewed from the stern. If it is not the rudder will have a different effect when heeled on port tack to that when Servo » mistakes I and others seem to have made, heeled on starboard. Less than 45° 4, Make sure that the rudder has enough Should be 60° each way movement, 60° each side. On my boat the tiller arm fouled the back of the boat before sufficient rudder move- Fig. 2 ment could be obtained. (It took me a lot of sailing time to decide more rudder was needed). I cured this by Rudder Rudder wire twisted that it bends the mast. 13. Glue ail knots—one is sure to come undone at the most critical moment if you don’t! 14. Sew hooks onto the luff of the jib similar to the main and hook them on the forestay so that the luff of the sail does not sag. 15. Set the sails so that they are smooth — no creases or stretching marks. They should not be stretched out tight. They need to have a fair amount of bagginess or curve. 16. Adjust the sheets so that when the transmitter stick is at the end of its travel the sails are close-hauled, i.e., the end of the main boom is about 15mm off the centreline of the boat and the jib boom is around 40mm. The trim on the transmitter can be used to harden the sheets further if necessary. The sail winch servo must not be trying to pul] the main boom down into the deck which will prevent the servo reaching its full travel and re- duce its life. Also, the jib needs to be at a slightly bigger angle to the boatorit spoils the efficiency of the main. 17. Use ratchet gear on the sail winch transmitter stick so that it can be set and left. Self-centring control for the sails is no good. Well, that’s it, see you around the regattas and good sailing. Receiver Battery pack j, |
