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Old 06-11-2006, 08:25   #61
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I was being silly with 32kts apparent and full main and genoa rigged, close hauled at 45 deg apparent and doing just over 10 kts. I was having to spill the wind from the main in the gusts, but was really enjoying myself!

naturally, I had the main sheets in hand.
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Old 06-11-2006, 08:42   #62
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Captain Talbot, You are a 'wild and crazy guy' (American expression of admiration). My 'Admiral' would prevent me from having this much fun .... (sigh).

Rick in Florida
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Old 06-11-2006, 08:45   #63
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Next time I am over your way, we will have to meet up (I have relatives at Merritt Island)
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Old 06-11-2006, 10:51   #64
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When that time comes, the beers are on me.

Rick in Florida
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Old 06-11-2006, 13:02   #65
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Quote:
Originally Posted by yotphix
It is hard for me to believe that cats are just as safe as monos if cleating off the mainsheet in winds gusting to 25 knots can have this result. With the exception of course being dinghys, cleating of the main in a mono with winds gusting to 25 would result in a knockdown at worst and more likely just a wet rail.
You always keep the hatch boards in and the dorades bunged shut, right? Most of the monos I see sailing do not. A knockdown could turn ugly really fast.

-Scott
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Old 06-11-2006, 13:16   #66
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What are these hatchboards? dont use them on a cat, and dont have enough water on my vents to justify having dorades on them either.

A cat lives on top of the water, not in it!
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Old 06-11-2006, 13:49   #67
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Everybody knows that monohulls are way better than multihulls! whats wrong with you guys? Sure, if they get knocked down chances are they will sink due to flooding. The decks are not watertight, just read some of the hatch maintenance issues on the forum. And monohulls draw a lot more water, meaning they tend to stay out where its deep and safe. And monohulls look better, and are inherently faster. Whats wrong with you guys??
(just trying to drive the used catamaran market down a bit so I can buy one...)
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Old 06-11-2006, 14:25   #68
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Quote:
Originally Posted by Talbot
I was being silly with 32kts apparent and full main and genoa rigged, close hauled at 45 deg apparent and doing just over 10 kts. I was having to spill the wind from the main in the gusts, but was really enjoying myself!

naturally, I had the main sheets in hand.
Bloody hell, our last cat would have had a reefed main and a blade jib in 32 knots of wind and would have been doing 15 plus knots.

We once had her uo so high that we were all sliding down the deck. Definetly spilled drinks that day.
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Old 06-11-2006, 14:26   #69
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Canibul, will that actually work?

smm, I don't believe that yotphix understood the risk of cats with daggerboards at that point in the thread. You'd have to reread the whole thread.

Rick in Florida
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Old 06-11-2006, 14:28   #70
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Cat man do.. careful, that's an admission of .... gasp.... wait for it.... ...achohol abuse. .... If found guilty you may be banished to 1/2 boats.

Rick in Florida
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Old 06-11-2006, 15:16   #71
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Quote:
Originally Posted by Steve Rust
Cat's are incredibly stiff and have a higher initial stability than trimarans or monohulls. But that stability rapidly decreases once the windward hull lifts clear of the water.
Stability is a factor of where the centre of gravity is in relation to the centre of buoyancy. I would suggest that as a hull lifts, the CB rapidly shifts to the other hull, thus increasing stability. From this point it would slowly decrease to about 45 degrees heel, then the rate would increase until the boat hits its point of vanishing stability - dependent on the boat's design - but would generally be between 80-95 degrees for a cat.

The danger in lifting a hull IMO is the added windage under the bridgedeck. As well, the sudden decrease in wetted surface would cause an acceleration that increases the force of the daggerboard, resulting in an increased turning moment.

IIRC (and it's highly possible I don't) Kanter advocated keeping the leeward board down vice the windward - to me, using the windward board would be advised as lifting the hull would eliminate the boards thrust.
Any comment?

Kevin
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Old 06-11-2006, 15:58   #72
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Kevin... wouldn't using the windward board only create the necessary leeway should that hull lift? The boat would move sideways rather than lean, right?

Rick in Florida
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Old 06-11-2006, 16:12   #73
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Quote:
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Cat man do.. careful, that's an admission of .... gasp.... wait for it.... ...achohol abuse. .... If found guilty you may be banished to 1/2 boats.

Rick in Florida
I/2 boats!!!!! god no, the horror, the horror.

Actually the drink spilling day was while racing and we had a guru on board and it was a bit of a test to see just how far we could push our dear little boat. Obviously a lot further than I usually do, we cracked the 20 knot barrier that day in about 25 of wind. We had eyes like dinner plates.

Whenever the Guru sailed with us again he was not allowed a winch handle.

Dave
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Old 06-11-2006, 17:50   #74
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Quote:
Originally Posted by Lodesman
The danger in lifting a hull IMO is the added windage under the bridgedeck. As well, the sudden decrease in wetted surface would cause an acceleration that increases the force of the daggerboard, resulting in an increased turning moment.

Kevin
As the hull lifts, there is certainly an increase in speed as wetted surface is lessened, but once the boat is flying a hull, maybe 20 degrees and more, the boat begins to slow down as the perceived sail area is diminished. Ever see how slow a Hobie can go when flying a hull? We use to fly the hull high on a Hobie in the tidal flow of Stony Brook Harbor, and we could nearly stand still along side the beach in the 8 knot current. It was fun to see the expressions on the faces of the beach-goers.
The danger does come when the wind gets under the wing and continues pushing the boat over.
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Old 06-11-2006, 20:02   #75
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Quote:
Originally Posted by rickm505
wouldn't using the windward board only create the necessary leeway should that hull lift? The boat would move sideways rather than lean, right?
Rick - that's the way I see it.

fhrussell - that's an interesting observation, but I don't see how a 20 degree lean would reduce the sail surface area all that much. Leaners don't seem to have a deceleration problem when they get to 20 degrees. I wouldn't think sails spill air significantly until they're about 60 degrees from vertical. Any expert opinion on this?

Kevin
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