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[ rob denney rob@harryproa.com ph:(08) 9284 3483 ] [ website ]
Sailing "U" Diary Excerpts
Rob Denney's 5m prototype.
24 May:The rudders work, but what a mess! The forward one is lifted and folds back against the inboard side of the hull. It is pulled down with a string and is spring loaded with poor mans shock cord (old bicycle inner tube) so that it retracts automatically. The 5m long tiller is attached with a string universal joint to the trailing edge, which makes it the opposite of conventional tillers. This is a nuisance at first, but certainly keeps the helmsman concentrating. The weatherboard is also controlled with string through the same strong point on the bow as the rudder up and down line and the trampoline deck. Spaghetti City.
5m prototype.
Nothing broke, creaked or groaned, but the little hull twists like Adrenalin's (Gougeon designed radical Formula 40 tri with hulls free to pitch independently of the main hull) which is no bad thing, but the tubes will need wear surfaces, and the main hull tends to trim slightly bow down.
The trim should not be a problem once/if it planes. The rudders may need to be bigger, although fairing them up and shaping them properly may be sufficient. The tiller attachment point and the gudgeons need to be higher, and the wooden pintle needs replacing with carbon. The leeboard pivoting fore and aft on the beam is an easy solution and definitely works, but is probably not totally efficient due to tip losses.. Installing it in between the beams will add some weight, but introduce symmetry of distribution and load transfer.
"U" sailing a light breeze
Jib needs to be bigger, bottom bearing cleaned up and weather hull in big need of TLC. Time for a decision on the weather hull and the optimum beam. We have righting moment to burn and the drag when shunting means more helm is used than is ideal.
It is interesting. People who have not seen it and know nothing about it reckon it is rubbish and will never work. Those who do see it when I am present are usually too polite to say anything other than "isn't it different" type of platitudes. About 6 people have seen it sailing and all were impressed, making "it looks like shit, but wait until you see it sailing" sort of comments. Everyone is dead keen to come for a sail, until I try to arrange a time (Lake Samsonvale is a reservoir and you need a key to get to it) when they suddenly can't. Even in reasonably calm weather, the local yachties are falling all over themselves to help launch and rig, but won't get on the thing for love nor money.
Broken "U"
Mangled "U"
Flew a hull a loooong way up, dumped main sheet and it came down with a bang. Three bangs actually, as the beams both broke! Definitely not a load I had designed for, but they both went in the same place, which was reassuring, as was the knowledge that they had withstood the design loads I had allowed for and were not excessively heavy. Also tore a chunk out of the weather hull and provided some very good pictures.
Took it all home, reduced the leeward hull as planned, lowered the beam to 3m (lower than planned, but this is all that remains of the beams), changed from pocket luff to bolt rope so we could reef and went sailing on monohulls for a month or so. Re-launch is in three weeks time or the end of September, whichever comes first. Re-launched with easier rig, beam canting aft to lift the bow and a weather hull including a bunk. En route to the marina, the weather hull flew off the trailer at 40 mph, sailed over the car behind and hit the freeway. Few chunks missing, but fixable. Tough stuff, plywood.
End.