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This evening seminar was held on the Wednesday of Weymouth Speedweek and as usual it attracted a full house in the large upstairs meeting room at the Royal Dorset Yacht Club. Michael Ellison took the chair and the meeting progressed swiftly through a series of five minute talks with a halfway break to watch video footage of the weeks events. SLADE PENOYRE Slade has a habit of putting into practice those simple ideas which many of us may well have thought about but which rather fewer of us have actually bothered to try for real. An example is his suggestion to use an air bag hoisted to the masthead to right an inverted multihull, as now tried and proven by Harvey Bowden - see below. Slade's idea for '99 is to use a spinaker pole to hoist a bag of water to windward to improve the windward performance of a monohull cruising yacht. This could be applicable to many cruising yachts. It would not be so applicable to racing since it would contravene most racing rules. The water bag would be used only for long windward legs, just as a spinaker is normally used only for long off wind legs. The time and effort required to set up the system would be at least comparable to setting a spinaker so it would not be appropriate for short legs. Slade showed a suitable bag manufactured by a company called Seaflex and intended for use by divers to raise heavy objects from the seabed. These sturdy bags are made from a plasticised fabric and fitted with strong rope attachments. After rigging the spinaker pole the bag would be lowered into the sea to fill it then raised again. Such a simple idea should not cost much to try out. Slade is keen to get in touch with monohull owners who would like to collaborate in trials. HARVEY BOWDEN Harvey Bowden brought his highly tuned and stripped out Firebird catamaran to this years Speedweek and used it not only for speed trials but also to demonstrate Slade Penoyre's suggested self righting method. He has now tested this self-righting method seventeen times with success on all but two occasions. Unfortunately one of the two failures was during a demonstration on the Tuesday of Speedweek and resulted in the breakage of an expensive carbon fibre mast. During the interval we studied a video of the demonstration. The main shrouds are both fitted to tackles and with the cat capsized to a fully inverted position the shrouds were adjusted to incline the mast under the water. An air filled bag, which I think was one manufactured by Seaflex (as above), was then attached to a spare halyard and winched to the masthead. This successfully brought the cat to an angle of heel somewhat more than 90 degrees, floating on one hull with the mast tip supported by the bag. The next stage is to incline the mast the opposite way to cause the boat to overbalance and flip upright. Unfortunately at this point the shroud out of the water was inadvertently slackened off whereas it should have been kept tight. This meant that as the cat very suddenly flipped upright the mast stayed roughly horizontal and smashed against the hull. Harvey immediately ordered a new mast but obviously the boat was out of action for the rest of Speedweek. Slade has since been thinking about avoiding the need for adjustable length shrouds. In this case the final stages of righting would be by a pole and water filled bag deployed from under the bridgedeck. During the interval we also watched video footage of Orion travelling at well over 20 knots on the speed course. At these speeds the lee hull throws up a most impressive bow wave. BOB QUINTON Bob has designed and built an 8' long funboat called 'Broadboard'. This is a wide shallow square ended skimmer with a small version of the rigid slatted wing rig he used on his day sailing cat at previous Speedweeks. The Broadboard has been extensively tested and found to be very easy to handle. Bob is offering the design as a kit or as a completed craft and has taken several orders. The wing is pivoted from the top of a short mast and can be inclined to produce both lift and forward drive, or can be set horizontal when you want to park. The boat sailed well at the beginning of Speedweek but was then put out of action when the transom became partially detached from the rest of the hull. NICK POVEY Nick has been thinking about possible ways of improving the performance of sailboards - as if one needs to! Nicks ideas follow on from tests by Bob Spagnoletti using a sailboard with a stepped planing surface. The idea is that splitting the planing surface into two longitudinally separated regions will improve longitudinal stability and also allow small angles of attack without excessive wetted area. It is a principle which has often been tried on fast power boats and seaplanes but has never become really popular. To develop the idea further Nick has built what he called a 'development platform', this being a sailboard with a long thin flat bottomed hull under which various types of planing surfaces can be attached in various positions. At present there are simple plywood planing skids, one at each end. Early trials are showing promise. As an aside, the author of these notes has in his workshop a similar sort of 'development platform' which did not quite make it to this years Speed Week. My boat would be categorised as a single handed dinghy rather than a sailboard since it does not have a universal joint at the mast foot. It is smaller and lighter than almost any other dinghy I have seen, being perhaps rather too close to a 'sinker dinghy'. Various lifting surfaces can be used and if the boat will sail well enough I intend to try relatively deep lifting hydrofoils and to compare these with planing skids and with the narrow hull in displacement mode. One possibility I have in mind is a hydrofoil which lifts the hull in the mid speed range then becomes a planing surface at the top of the speed range. It occurred to me that Torix Benet's boat might also be a suitable platform for such experiments - the fittings on the back of each of his hulls might serve as mounts for my prototype foils - what do you think, Torrix? NEILS HARBOSH Last year Neil showed us his imaginative 'butterfly boat' with two masts splayed apart at 90 degrees. This year he brought along a collection of boat parts from which to build some more interesting boats. One was a trimaran with floating free wheeling wheels in place of outriggers. With some hacksaw work this trimaran could be converted into a kite powered boat with small planing floats in place of the wheels. The boat sailed well in kite powered mode but Neils said he could do with stronger wind. The kite is a 'Whipica' kite which can be relaunched after landing in the water, i.e. it does not become a huge bag of seawater as do some kites. The wheeled trimaran was fascinating. The wheels have fat inner tube tyres about 1400mm overall diameter. The cross beam is a pole and also serves as the axle for the wheels. The idea is to save skin friction but Neils admitted that he is not sure how well this works and with the simple bearings used there is no certainty that the wheels will actually rotate when the craft is sailing. I believe that a steamship with floating wheels was built in Victorian times. Considering the construction materials in use in this era I cannot imagine how the wheels provided enough buoyancy unless they were as big as the one which has just appeared opposite the Houses of Parliament in London, in which case they would surely present a lot of windage. CHRIS EVANS Chris bought two boats, one his very pretty daysailing trimaran with main hull styling based on a Canadian canoe. This now has a new rig, the unstayed una rig we saw two years ago being replaced with a much sturdier sloop rig with stayed rotating wing mast and fully batted mainsail. Chris's second boat this year was a new trimaran designed in collaboration with David Chinery. Last year David Chinery showed us a radio controlled model of a trimaran with retractable foils which supplement stability in displacement mode as well as allowing foil borne sailing in the right conditions. Just 12 months later Chis has completed a 7.4m long version for daysailing with a crew of one or two persons - that is pretty good going, especially considering all the intricate parts and custom made metal work in the boat. One of David's concerns was to avoid pitchpoling with strong wind aft of the beam. To avoid this, the craft has a stern rudder in the form of an inverted tee foil with manually adjustable incidence. This can be used either to hold the stern down when running or as one of the lifting foils when the craft is fully foil borne. The other two lifting foils are inclined surface piercing foils mounted under the forward cross beams and are fully retractable under remote control from the steering position which is right aft. The hull is of 3.5mm ply coated in epoxy and to save weight there is no cloth sheathing. Chris reckons that this type of construction can rival more expensive composite materials for lightweight experimental craft which are not intended to have a really long working life. BRISTOL SPEED SAILING TEAM. The Bristol Speed Sailing Team can be relied upon for light hearted entertainment and this year these diversions included a Speedweek song with guitar accompaniment plus jokes by Bob Date. Since I missed some of the words of the song and the jokes were not all printable I shall report only the impressive technical achievements made this year. Last year the Bristol Speed Sailing Team produced a Dart catamaran fitted with beautiful forward foils designed by the late Dave Keiper but at that time the stern foil was not quite right. This year the stern foil arrangements have been much improved with an inverted Tee foil mounted on a nicely made framework of welded stainless steel tubes which attaches to the hulls right aft and to the aft cross beam. All foils can be easily retracted for sailing in shallow water. In the light winds on the Wednesday of this evening meeting the boat achieved 14 knots, the record for the day. FRED BALL Fred was sailing his 18 year old catamaran with inflatable hulls, the forerunner of the successful Catapult design. This year Fred has modified the boat by building plywood longitudinal structures which fit above each hull to stiffen the hulls and also to allow the cross beams to be raised about 300 mm higher off the water. The higher cross beams have reduced drag since they no longer plough into the wave tops but increased weight has offset this gain. The hull still lacks stiffness since the ageing fabric cannot contain the full air pressure for long. Fred admitted the craft is at or beyond the end of its working life. JOHN LINDSAY AND CHRIS HAYLE. These speakers gave separate presentations but I shall report them together since they make an interesting comparison. John Lindsay and Chris Hayle are both marketing commercially manufactured sailing hydrofoils, these being the Hobie Trifoiler and the new Rave. John has brought a Trifoiler to Speedweek before whereas the Rave was new to Speedweek and Chis brought two samples for prospective customers to play with. These products are in direct competition, both being flying hydrofoils designed to be road trailable and to carry one helmsman plus one optional passenger seated in a comfortable cockpit. Both designs have fully immersed variable lift foils and small floats at each end of a longish crossbeam, the lift of the foils being automatically controlled by a mechanism connected to articulated surface sensors. Both craft have anodised aluminium extrusions for spars, cross beams etc, both are steered by a tee foil mounted aft and both have reefable fully battened sails but that is about the end of the similarities. Foil lift control on the Trifoiler is by tilting the whole foil assembly about a lateral axis. Foil lift control on the Rave is by actuating only a full width trailing edge flap on each foil. Presumably these trailing edge flaps can be controlled by relatively small forces explaining why the surface sensors are much smaller and neater on the Rave than on the Trifoiler. The two craft have quite different rigs. The Trifoiler has a biplane rig with a mast step at each end of the cross beam, this giving a reduced height of center of effort compared with a comparable single mast rig of the same area. The Rave has a more conventional fore and aft rig with self tacking jib and very square headed main. The main is boomless and the clew of the main is sheeted to a single point near the transom. When the sheet is eased a lot of twist appears in the main and perhaps this makes it possible to spill wind high up whilst maintaining drive from the lower part of the sail. The Trifoiler has foils moulded in composite materals, the foils on the Rave are welded from aluminium extrusions. The Trifoiler has composite laminated hulls, the hulls of the Rave are, I think, rotomoulded and have an internal stiffening framework of aluminium tubing. So how did performance compare? Chris Hayle said that the Rave does need a good wind to get foil borne but once it is flying it usually sails at around 40 knots with a maximum unofficially recorded at 46 knots. However, it has to be said that the Trifoiler actually put up the best non-sailboard speed of the week at 31.6 knots, the Rave did 24.5 knots. Amazingly, the best speed of the Trifoiler was only about one knot slower than the best sailboard speed. Chris suspected that the Rave could have been adversely affected by some peculiar air turbulence caused by the way the wind flows over Portland Bill. I must admit that I would never have expected flying sailing hydrofoils to become a commercial possibility. I would have thought that such craft would be far too vulnerable to damage by grounding and hence only suitable for mad experimenters who are prepared for frequent rebuilds. This must be an inherent difficulty but the foils are robustly made, especially on the Rave. I noticed one of the Raves moored over a hard seabed with the foils left locked down as the tide receded. At first the small waves caused the foils to bump on the rocks then the foils came to support the full weight of the craft. I was surprised that all this caused no obvious damage and indeed it seems to be the standard way to park a Rave. Recently a Rave foil did catch a small tethered buoy while sailing and the foil came off best - Chis was able to show us a battle trophy in the form of the severed buoy dangling from a mangled length of 6mm cordage. I do wonder what would happen if a foil caught a heavy mooring chain while sailing fast, I suppose that the helmsperson just has to make sure this never happens. Despite my scepticism, commercially built sailing hydrofoils are now shipping, to use the parlance of the software industry. Chris Lindsay claimed 200 recent sales, mostly in the States. They really do get foilborne and in the conditions which suit them they can be significantly faster than conventional monohulls and multihulls. However, unless we see further developments, the sailboard continues to offer the most knots and by far the most knots per buck. As a big bonus the sailboard gives you remarkable seaworthiness, damage resistance and ease of transport on a car roof rack. But you do need to be reasonably athletic and highly skilled to make the most of a sailboard whereas it is reckoned that any couch potato with sailing experience can climb aboard these hydrofoil craft and drive away. You and your girlfriend sit in comfort in a light aircraft style cockpit and it sounds to be as easy as taking a new sports car out of the show room, not that I got the chance to try it myself. For quite a few customers perhaps this could be a winning factor. JOHN MONTGOMERY AND SON ALEX Alex Montgomery presented a superb 1/50th scale model made by his father and representing his father's proposal for a catamaran to compete in the forth coming race i.e. 'The Race'. During the past few Speedweek seminars we have seen some beautifully made models but this one was really excellent, to the best professional model making standard. The boat represented is a huge Catamaran with slewing hulls and no less than four independent sail rigs each mounted above one of the four slewing pivots at the junctions between the hulls and the two cross beams. Dimensions are 37m hull length, 22.6m beam, approximate sailing displacement 22 tons. Each rig has a boom extended ahead of the mast to support the forestay in the manner of the proprietary 'Aero' rig. This gives no less than eight high aspect ratio sails. The booms are made large enough to be the only working platforms required for the crew to handle the sails and they also house roller reefing drums for each sail. The unstayed wing masts rotate independently of the booms and the hull slewing. The design of the mast pivots carries cantilever bending moments directly from the masts into the cross beams reducing stresses in the hull structure. There is three meter wave clearance under the cross beams and the central pod with crew accommodation is mounted even higher. There are no trampolines, the crew accessing the working platforms on the booms via passageways though the centre of the hull slew bearings and on trolleys which run though the hollow cross beams, like miners getting to a tight coal face. I must say that the expanse of trampolines on boats such as Steve Fosset's 'Playstation' do look to be lots of windage and quite heavy when all is waterlogged so perhaps this is a better way for crew to get to their working positions. The slew hull design allows the effective length of the craft to be increased downwind to resist bow burying and helps in minimising aerodynamic interference between the four rigs. A final point is that the centre boards of Jon's proposed catamaran are mounted alongside rather than through the hulls, following the arrangement on Jon's Catapult design. The boards and rudders are all pivoted so that there is nothing to break off through hitting floating objects, this being a mishap which has befallen so many fast ocean racing yachts. If this boat reaches the start line it must be a formidable contender. Apart from anything else it would be bigger than much of the competition. Also, with four independent rigs, relatively low center of effort for minimum capsise risk and damage resistant appendages this might just be the craft that wins the race after all the others have broken up, broken down or sunk. Altogether an impressive proposal but as Alex said it still needs a lot of money plus a lot of hurry to get it to the start line. I am sure the Montgomeries would be very interested in any realistic ideas to achieve this - wouldn't you be? JEAN HURTADO Jean Hurtado starts his innovative boat designs with a balance of force vectors. Previously this lead to a narrow hull and rig which both roll through 90 degrees when tacking so inclining the rig to produce aerodynamic lift to just balance the weight at a design apparent wind strength. This year Jean has built a new boat which If anything is even simpler in concept but is still based on the use of sail force to balance the total weight. This time the sail is a low aspect ratio inclined fore sail mounted forward for downwind sailing. Again, the idea is that at the design apparent wind speed the weight is almost entirely carried by the rig. Hull drag is then of little consequence and so a crude looking hull design will suffice, in this case three aluminium drums fixed to a simple triangular frame. Best speed to date is just 1.4 knots so, as Jean said, 'everyone will be really keen to copy my ideas'. One can imagine that the concept would work much better given just the right wind strength. DAVID CHINERY David showed us a neat little model of an articulated oar which he has designed. Effectively the oar bends at the rowlock such that when you pull on the inboard end the blade moves in the same direction as you pull, not the opposite direction. This allows you to row facing forward which is much pleasanter than conventional rowing. The mechanism looks quite simple to make, it is based on cords and pulleys rather than gears or other precision machined parts. David said that he had patented the design and he told us a bit about the process for applying for a patent. There certainly have been various other devices which allow forward facing rowing by comparable mechanisms but David said that his design has the advantage of avoiding excessive forces within the mechanism and can be used on almost any row boat without strengthening the gunwhale or needing special rowlock mountings. Just a short length of cord suffices to hold the device to the gunwhale. IAN HANNAY Ian made some comments based on observations from on board his yacht 'Melina of Fleet' which acted as mark boat at one end of the course. Ian commented that this has been an excellent Speedweek with better speed sailing weather than we have had for many years. Impressive speeds had been recorded and it appears that the performance gap between the sailboards and the non-sailboards is closing. He said that in very rough terms non-sailboard speeds are now around two third thirds of sailboard speeds whereas in previous years they were about half sailboard speeds. (As stated above, the best sailboard speed this year was actually only about one knot faster than the best non-sailboard speed). Turning to details of boat design, Ian felt that some competitors are not giving enough attention to rigs. He suggested that some of us are spending a lot of time and money producing nice hulls then limiting performance by using relatively crude rigs, often inappropriate rigs transplanted from some other craft. In particular, Ian felt that standard sailboard rigs were unsuitable for use on other types of craft which potentially have much greater righting moment than a sailboard. Multiple rigs to give drive with lower centre of effort could be given more consideration (two boats with such rigs did compete this year and both achieved excellent results). I could guess that Ian is a monohull man at heart when he said that a multihull needs to be sailed like a monohull - i.e. you should be flying a hull or two. BOB DOWNHILL Bob Downhill made a quick mention of the hull drag measurements which he and Fred Ball had been making during this Speedweek. These measurements are quite simple to make and potentially most interesting. The method is to tow various craft using Fred's 28 hp Dell Quay dory which is fitted with a good speedometer and a rusty but apparently accurate spring balance attached to the towline. Various craft had been measured and Bob appealed for more to come forward. Most of the drag vs. speed plots showed a distinct hump in the mid speed range and Fred did comment that in some cases this could be due to the effect of the dory wake rather than the characteristics of the towed hull. I find this a bit worrying - presumably the towline does need to be long enough. I hope that in due course these results can be presented in an AYRS journal. Bob Downhill concluded by saying how much he had enjoyed this excellent 25th Weymouth Speedweek. He hopes to see us all back next year. John Perry Visit AYRS' new official site on the World Wide Web at: http://www.ayrs.org Find all AYRS publications, 1955 to 1998, how to join AYRS, search our online index, and more!
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