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post #1 of 7 Old 06-03-2010 Thread Starter
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A question about balance

I Sail a 1979 27ft Sun Yacht. She drafts 4.6. The boat seems to lean back towards the stearn when she really gets going. The stearn dips at least 1 foot. Is this normal?
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post #2 of 7 Old 06-03-2010
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Originally Posted by YamasSea View Post
I Sail a 1979 27ft Sun Yacht. She drafts 4.6. The boat seems to lean back towards the stearn when she really gets going. The stearn dips at least 1 foot. Is this normal?
Are you talking about being under power? If so it's not really unusual for a boat to squat by the stern when being pushed hard, except that the Suns were generally a bit underpowered.

More details like what conditions are you discussing, the engine size, number of people in the cockpit ! and so on.... would be helpful.

Ron

1984 Fast/Nicholson 345 "FastForward"

".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)
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post #3 of 7 Old 06-03-2010
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Yamas, I think it was 10-15 years ago that the QE2 (and you know they don't give that to average skippers) actually bottomed out and did some damage near Cape Cod (Mass.) because even THAT ship "squats" at speed and the stern lowers.

With any displacement hull, as you move faster and displace more water, you dig a "bigger hole" in the ocean, and the stern especially drops deeper into the hole. You probably could trim more bow-down, but then you might find the trim was wrong when you were sailing at slower speeds. Getting a hull design to "do" it all and "be" it all under all conditions, is quite a good trick.

If you've got weight added in the stern (tankage, batteries, anchors and chain, bigger than original engine?) you might try shifting it forward to see what difference it makes. Or sending a couple of heavy crew forward as ballast--that's sometimes a very good way to trim for conditions.
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post #4 of 7 Old 06-04-2010 Thread Starter
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Thanks guys... She squats under power and while sailing. I have a 9.9 outboard. It happens even with one in the cockpit. It happens at about 5 to 6 mph on my GPS. Would adding more jib help maybe. I have a 160 genoa that i could use.
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post #5 of 7 Old 06-04-2010
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Six knots in a 27' boat is probably hull speed, and at that point yes, you certainly will be digging a hole in the water. And slipping into it. Trim what you can,don't worry too much about the squat.
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hellosailor,

Thanks bro
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You might alleviate some of the squat under power by changing the tilt/trim on the outboard.

Ron

1984 Fast/Nicholson 345 "FastForward"

".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)
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