I will bet this keel was designed shortly after Australia II won the America’s Cup.
It’s a dead ringer for Ben Lexcen’s revolutionary keel.
But here’s the thing, while end plates are good and bulbs can make shallower keels more efficient than they would be otherwise, Australia II‘s keel was designed to get around or fool the 12-meter rule, not because there is anything intrinsically good about this design.
And yet a bunch of cruising boats at the time ended up with keels like this that will catch any piece of floating debris and have large vulnerable wings, just because it was fashionable.
Watch out for the results of trends like this when buying a boat.
Hi John and all,
Two observations:
Going aground in mud and laying over and you bury that fin like a mushroom anchor and you are not going to be pulled off (without ripping the fin off- a very real possibility) till the tide rises.
Going aground on a relatively flat sand bank near high tide. If you neglect to pull the boat over when you can, the boat will stand on its keel wings until a not necessarily strong wind (or any imbalance) will topple the boat over. If this takes long enough so the tide is really far out, the boat may be damaged as it falls over and lands on its side on the hard.
My best, Dick Stevenson, s/v Alchemy
Hi Dick,
Both are very true dangers.
My CS 40 has a winged keel, and is good to windward, so your comments attracted attention! If I had the deep keel, fin draft would be 7 feet not 5.6 ft. I thought you glossed over or dismissed as a fashion statement any discussion of the hydrodynamics which are at the heart of the discussion. Thus, I am no wiser. The A2 design did not get around the rules, it complied, and won. Is this positive evidence?
Good tips regarding getting stuck..ie don’t. And to be objective, we caught a raft of kelp this year, and dinged a wing 5 years ago. My mistakes and who hasn’t?
Cheers
Hi Ian,
Good point, that said, these are short thoughts, so not the place for a long dissertation, and I did point out that end plates were a great idea.
But I would stick with my thinking that, for example, the reverse leading edge angle is not a great idea given its ability to foul, and as far as I know, it has no performance benefits, so is more about fashion than function.
As to A2, she did indeed find a loop hole in the 12 meter rule to be faster in fact than the rule predicted her to be.
Agree re reverse angle!
Hi
i own a Contest 37 with one of these keels, I believe the purpose was to create a damping effect so the boat feels like a larger boat in rough seas. Contest yachts did not design it to win any races.
Hi Myron,
Hum, yes making the boat shallower does, in some ways, make the motion more comfortable. Think boats like the Ovni and Boreal, but given that the centre of gravity of the keel will be in the same place in this case I can’t see that doing anything to make the motion more comfortable, although there could be something I have not thought of. The other thing that supports my theory is that wing keels seem to have gone out of fashion, which would suggest it was more fashion than practicality the first place. Developments that actually do something useful tend to stick around.