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Description: | Design analysis . . Two small yachts by Richard Carr and Colin Mudie The Dragonfly and the Audacity are two small yachts within the price range of a family car, one of which is intended for estuary and inshore sailing, the other for offshore cruising and extended voyages. In this analysis, the authors. one of whom, Colin Mudie, is a naval architect and yachting journalist of considerable experience, have examined the functions of the two boats to see how they are related to the design, and how the design might be improved. The yachts tested lifelong to two industrial designers, Len Wingfield and Ronald Brookes, who were asked to report on their boats using the sort of critical approach they would normally adopt when tackling an industrial design problem. Yachting, like horse racing, was once thought of as the sport of kings, but since the last world war a revolution in the Use of sail has been taking place and yachts - at least the smaller variety - are now owned by a great number of people who use them for weekend and holiday sailing. The average owner of this kind of boat is not a fanatic but has bought it after all the other requirements of modern family life - a house, a refrigerator, a car and so on - have been met. Indeed, if one looks into the future, it may not be long before a boat is regarded as an essential requisite for most people in the same way that a car is today. The main requirements Broadly speaking, the requirements for the type of small yacht mentioned above are usually along the following lines. First, the cost of the boat is extremely important and should be relatively analogous to the cost of the family car, so that the boat can be bought without great financial strain. Unlike the car, however, it does have the advantage that it is a one-off purchase that may last 10 or 20 years, will hold its market value over a long period of time, and (like a car) can have equipment and fittings added to it whenever the owner is able and feels inclined to do so. Second, it is essential that the small yacht provides some form of overnight accommodation to allow people to spend the weekend in secluded anchorages. Indeed, for those who live too far away from the sea to make sailing anything but a weekend and holiday occupation, the cost and trouble of booking in at hotels for overnight stops would be out of all proportion to the kind of recreation a small boat provides. The sleeping accommodation must be for at least two people, but preferably for two couples or one couple and family. Third, the sailing performance of the small yacht must be good enough to provide the pleasure of being under sail but need not be in any way exceptional. It is usually enough to be sailing as such and competitive sailing is rarely taken seriously with this kind of boat. Fourth, the small boat is frequently used under power, even though the term 'motor sailer' is most unpopular with the yachting Fraternity, and an engine, either inboard or outboard, is essential to ensure reliability and reasonably ccurate timing during weekend sailing excursions. For families that have to be home at bedtime and fathers who must be back in the office on Monday morning, this is an important consideration. Fifth, the great expansion in sailing since the war has put a premium on deep water moorings and on winter lay up space and yards. It is therefore an advantage if the yacht has a shallow draught, so that she can be moored in shallow water and taken home on a trailer when the season is over. Her convenience is even greater if she can lie upright when aground without risk of damaging the hull. Sixth, though owners of this type of yacht are initially attracted by the thought of the cheapest possible maintenance costs, most take considerable pleasure at 'fitting out time' in painting and varnishing and adding small improvements. The design should take some note of this. The point mentioned earlier -that owners often add equipment and fittings over a period of time - also means that these yachts can be designed to allow for this to reduce the initial outlay. The last but not least requirement is safety. It is not always possible but it is extremely desirable that a yacht should have sufficient built-in buoyancy to remain afloat if swamped, and that she should have sufficient ballast to be selfrighting if knocked down in open water. If the yacht is to be taken offshore, then a cockpit which is self-draining or at least watertight is essential. Safety, of course, also covers such basic points as adequate scantlings for the yacht and suitable fittings. The attachments of the rigging holding up the mast must, for instance, be beyond reproach. These requirements include all the main considerations that must be taken into account by people designing - or buying - a small yacht. They formed the basis of the analysis of the two boats which follows. Both are intended for family use, both are in the price range of a family car (ie, from £500 to £1,600) and their main difference is that one is intended primarily for weekend coastal or estuary sailing while the other is suitable for extended off-shore cruising. Indeed, in experienced hands, there is no reason why it should not be sailed to the Mediterranean or even across the Atlantic. The yachts were also designed a few years ago and it is possible that in some particulars fashion has changed since then. Both have small fore triangles with the forestay attached some distance below the masthead while today very few yachts of their size are designed without the slightly cheaper and simpler masthead fore triangle rig. (caption) The position of the outboard motor on the Dragonfly is port of centreline, clear of the transom-hung rudder. This offset position is chosen to counteract the tendency of a right handed propeller to turn the boat to starboard. (caption) However, when the boat is heeled to starboard, the motor loses effectiveness because the propeller races in broken water. In this case, a centre position for the outboard motor would be more suitable for rough weather use. (caption) When sailing in reasonably clear water, the outboard motor can be kept ready for use although clear of the water. The mainsheet is also well away from the motor so that it does not foul it when the boat goes about. (caption) The Dragonfly under sail. For overnight cruising, the cockpit can be put under canvas to provide extra berths. (caption) The Audacity under sail, showing how the rolled sides give her a lifeboat-like appearance. (caption) In the open sea, however, it is better to stow the motor. The Dragonfly cockpit is arranged so that a seat can be removed to enable the crew to get close to the motor to do this. (caption) But a better solution would be to mount the motor inboard. This could be done by having a propeller shaft tunnel integrated into the hull. It would protect the engine from spray and make maintenance easier, though it raises problems of turbulance and ventilation. (caption) The shallow fixed keel of the Dragonfly is not very efficient when sailing to windward in rough water as it does not reach through the surface drift and broken water. The smaller of the two boats is the Dragonfly. This is an unashamedly inexpensive boat but, within that overriding limitation, he is well designed and well built. Her construction is in the conventional manner of plywood applied on frames and stringers. The frames are perhaps bigger than necessary, but this is probably due to the convenience of using stout frames when building this way. Inside, her furnishings are cheap and simple, with varnished plywood used simply and soundly. There are few storage lockers, for example, but this is to keep cost to a minimum rather than because of insuffcient space. The cabin has sleeping accommodation for two eople and can sit four people for tea quite comfortably. On the other hand, the boat has a fine big cockpit with plenty of room for fishing or picnics. In inshore sailing, this is an important feature and more than offsets the fact that there is little room elsewhere on leek for people to sit and sun themselves. The other points for and against the Dragonfly are that, although he twin keels and ballast keel enable the boat to be kept in drying ut harbours or shallow water and to be easily/railed, they may compromise the sailing performance a little (although Desoutter has escribed the performance as "sparkling"). This is a point of great controversy and it may be that this effect is due principally to the cutting down of sail area and ballast from the point of view of economy in first cost. This attitude can be seen in the fittings on the yacht which are all to the minimum dimensions possible. A larger size throughout would not have been out of place although it is difficult to argue that those fitted were in anyway inadequate. Again, is difficult to argue against the big cockpit which fits in perfectly Pith the proper purpose of this version of the boat which is inshore family cruising. However, the occasional owner will be tempted to choose his weather and nip across the Channel with the hazard of eing caught out. No amount of telling owners that this is not what he is designed for will convince everyone that such a handsome and seaworthy looking yacht should not be used for this (except in the version fitted with a self draining cockpit). Finally, it is generally considered sufficient in this kind of yacht to leave the owner or his dealer to fit an outboard motor bracket on the side or the transom. To provide more extensive facilities for an outboard engine is an expensive complication. However, it is such an important part of a yachting weekend that it deserves a great deal more consideration. The Dragonfly we tested had the outboard motor mounted on one corner of the transom where on one tack it either had to be removed or was covered in spray, while on the other the propeller did not even touch the water, so that propulsion had to be either by sail or by motor but could not be by both. An efficient outboard motor fixture should be provided as standard. The Audacity The second yacht, the Audacity, is altogether a more ambitious craft and therefore offers greater scope for examination. The boat was designed to take advantage of the moulded plywood construction developed during the war for building Mosquito aircraft and so to dispense with traditional, more complicated and expensive methods of construction. By this means, it was also hoped to batch produce a small, seaworthy craft in the lower price range -the Audacity was originally sold for under 900. The exact requirements for the Audacity were also rigidly laid down by the News Chronicle and the original builders of the boat, Walter Lawrence Ltd. These requirements were the result of a survey which called for a four berths b shallow draught c trailability d good sailing performance e inboard engine; and f reduced maintenance cost by virtue of home maintenance and laying up. (caption) On the Audacity,the deep centre-plate is highly efficient when sailing to windward, especially in rough water when it 'grips' the water below the surface drift.. (caption) The large, deep open cockpit of the Dragonfly is unsuitable for offshore sailing in bad weather when waves may break inboard, but it provides room for four people, good security against falling overboard and helps to make rescue operations easier. (caption) The small, self draining cockpit of the Audacity, however, Is essential for extended offshore cruising, but in rough weather there is a risk of crew being thrown overboard and rescue operations would be difficult. In addition, the rolled type side deck and glass fibre moulding for the doghouse and coachroof made it possible to simplify building methods and reduce the boat to virtually three mouldings. Owing to the strength inherent in the shape of ply itself, frames and timbers were not required. Bulkheads give athwartships rigidity, stringers give fore and aft strength, and continuous bunk fronts also act as fore and aft girders. The Audacity is, in fact, an excellent boat for serious cruising. The snug rig, self draining cockpit, rolled deck sides and adequate ballast make her safe for extended offshore sailing, and her exceptional accommodation is big enough for her crew to live comfortably at sea and at moorings. On the other hand, she is not a particularly suitable yacht for family weekend parties, since the cockpit (which is appreciably smaller than that of the Dragonfly) will not seat more than three people in comfort and the rolled top sides leave little room on deck. Lack of deck room and small sail area also mean that she is not really suitable for racing, since there is not enough space for a crew to work in ease, though for less rigorous sailing the facilities are adequate. The accommodation, on the other hand, is very handsome for a 20 ft boat, providing good sleeping room for four people as well as a private W.C. The galley, which can be placed either below the bridgedeck or amidships on the starboard side (in which case the fourth berth is virtually lost) is quite adequate and the stowage for ship's equipment is very good. Stowage and lockers for crew's clothing, however, is so poor that they would probably have to keep their gear in kit bags while at sea. But, as with the galley position, it is really a case of inadequate lockers and four berths, or good lockers and three berths. Space had, in fact, been increased on the Audacity we tested by cutting away part of the ply bulkheads without, apparently, any detrimental effect on the strength of the ship. The cabin is also affected by the steep drop from the bridgedeck, over which one has to climb to go below. This is a big safety bonus at the expense of giving the cabin a closed in, claustrophobic atmosphere - another point to consider in relation to the use of the boat. And although the glass fibre moulding for the doghouse and coachroof has increased the cabin headroom (and is also leakproof), it appears to have been made to replace a wooden structure, while a more imaginative use of glass fibre might have given the cabin a greater feeling of space and airiness. Similarly, although the shallow bilges of the boat make a very desirable building form, any bilge water in the boat is immediately flung about and would quickly wet bedding and other equipment. For offshore cruising, it would probably be better to mould in a small reverse turn at the centreline to the keel to contain the bilge water. Criticism can also be made of the engine position which is not really suitable for use and maintenance offshore because of limited access through a hatch in the cockpit sole. Finally, the Audacity carries a relatively small rig, if anything a little old fashioned now, and when the boat is heavy with cruising equipment on board, her light weather performance is poor. Moderate to strong winds are needed to bring her to life, and she is probably much happier at sea than running close to shsore. (caption) The iron keels of the Dragonfly enable it to go ground in comfort and safety, and prevent mall rocks or anchors from damaging the hull. (caption) The Audacity, however, would heel over if it went aground on a hard surface. It would then be most uncomfortable on board and there would be a risk of damage to the hull so that good moorings are very important. (caption) Of course, a conventional, deep keeled yacht would be even worse offend unlike both the Dragonfly and the Audacity, cannot be put on a trailer and laid up at home. Summing up Generally speaking, these two small yachts fulfil entirely different functions, even though, like all boats, they overlap to some extent. The Audacity is a high class vessel and in style a smaller version of the classical ocean racing and cruising yachts for which her designers are famous. Her rolled decks and round bilged hull give her a great air of confidence and safety and throughout her fittings and equipment, seamanship has come before cost. As the more ambitious vessel, she is more open to criticism, but generally speaking she is the most successful version of her type to appear since the war. The Dragonfly, also designed by a successful ocean racer designer, stems more from the dinghy and probably attracts the dinghy sailor who wants a family boat. Both have the advantages of shallow draft but the Audacity would probably not like drying out regularly. Both are simple and easy to haul out on to a suitable trailer to be taken overland to other cruising grounds or home for the winter; and both, once the initial cost is over, would be cheap to maintain although the standard of maintenance, like everything else, depends entirely on the individual owners. Any analysis of the two boats cannot but end on the note that sailing performance depends to a very great extent on the experience of the owners and the amenities depend on the care, time and money they lavish on their yachts. (caption) The Dragonfly being winched on to a trailer for towing to a new mooring. The more usual method is to float the boat on to its trailer, as is done, right, in the case of the Audacity. Using a Land Rover, the operation is remarkably simple for a boat of her size. The boat can also be parked and used as a hotel while on the road. | Source: | Vads | Creator: | Artist: Richard Carr & Colin Mundie | Identifier: | http://www.vads.ac.uk/large.php?uid=8291... | Go to resource |
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