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Duncan Gibbs
09-30-2015, 08:15 AM
https://farm4.staticflickr.com/3731/9451280287_894db4f775_b.jpg

CWSmith
09-30-2015, 12:15 PM
Do you really think the extra 10 feet of hull behind the main results in a much faster boat? It must cut down on maneuverability and tactical ability.

Peerie Maa
09-30-2015, 12:50 PM
Do you really think the extra 10 feet of hull behind the main results in a much faster boat? It must cut down on maneuverability and tactical ability.
Yes, it increases waterline length when heeled, so is a go faster feature.

CWSmith
09-30-2015, 04:28 PM
Yes, it increases waterline length when heeled, so is a go faster feature.

Actually, increasing the waterline increases the MAXIMUM hull speed of a displacement hull. I'm not at all sure that it increases speed under all conditions. Specifically, in light air all you do is increase whetted surface and with it the drag. Then there is the fact that boat races are not run like drag races. I don't think that hull is as maneuverable as something who's length scales with the boom.

Duncan Gibbs
09-30-2015, 04:51 PM
The square metre boats usually have light displacements (therefore lower wetted surface), long water lines and short, but full keels which are ideally suited to the high aspect rig they carry. I'm not suggesting they have the same kind of manoeuvrability as a modern fin keeled boat, but are perhaps similar to Dragons. That long waterline helps the boat stand up to its rig as well.

John B
09-30-2015, 07:54 PM
In light weather the boat sits and sails on a shorter waterline , therefore less drag. As the wind increases you put in more counter and sail faster than your static waterline would allow. My boat was a 31 ft waterline which remained competitive with more 'modern' boats with say 36 to 38 ft waterline.
Of course all that is dependent on the age / style of boat. Typically a counter stern boat from say , 1880's or so or one that was built more 'cruisy' with a higher angle from the water to the counter might not put her WL in early,If at all. So those types speeds are constrained by design. I often see them lauded as fine boats here and think " what a waste".

Those SQ M boats and raters and similar , typicaly from about say 1890 on would put the counter down to some extent at quite low wind speeds.
Of the boats I raced regularly against and as an example Prize ,from circa 1923 has a relatively short counter and longer waterline compared to my boat from the same designer ( 1907), but the angle of her counter is also lower and because she has an enormous rig she pokes it in and is 'always' doing hull speed. I'd need 25 knots or so to get a nine knot hull wave.

But thats only empirical based information.

I went looking for a picture of Prize but found this instead

http://i227.photobucket.com/albums/dd48/Waione_photos/classic%20regatta%2006%20and%2007/212_1274_1.jpg (http://s227.photobucket.com/user/Waione_photos/media/classic%20regatta%2006%20and%2007/212_1274_1.jpg.html)

hahaha . Billy Backstay with a hull wave around his gronicles and cresting behind the boat. The cleats are under water. The tip of that counter trimmed at 2 ft( 600 mm) above the water normally.
We were logging and GPS ing 10.3 static, in flat water , no tide, on a 30 knot day. The only time I ever thought of the expression " and he drove the boat under".
The boat we were racing was about 10 or 12 ft longer , but only had a fraction of boatspeed on us because she was one of those earlier types with a counter hard to get down
great day.
a blast from the past, the Waione's , Thelmas( little) and Prize's cleaning up the teams racing. even a couple of boating royals in thar.

http://i227.photobucket.com/albums/dd48/Waione_photos/classic%20regatta%2006%20and%2007/215_1512_3.jpg (http://s227.photobucket.com/user/Waione_photos/media/classic%20regatta%2006%20and%2007/215_1512_3.jpg.html)

John B
09-30-2015, 08:14 PM
Geez , I still can't find a photo of Prize, and I know I have heaps of em...
one... Chad doing his thing. Good sailor that man , I hope he doesn't read this cos his head 'll swell up.
thats a good fast hull wave
http://i227.photobucket.com/albums/dd48/Waione_photos/Old%20internet%20boat%20photos%20file/Chadontherail.jpg (http://s227.photobucket.com/user/Waione_photos/media/Old%20internet%20boat%20photos%20file/Chadontherail.jpg.html)

John B
09-30-2015, 08:41 PM
Still.can't. find..

but Iorangi using some counter under motor earlier this year. I seem to recall we were doing about 7.5 knots plus ,maybe. He was trying out his new motor and prop, later he had most of that counter buried and was up to high 8's or perhaps 9 for a while.

http://i227.photobucket.com/albums/dd48/Waione_photos/Misc%20and%20sailing%202015/2015-03-27%2018.28.35.jpg (http://s227.photobucket.com/user/Waione_photos/media/Misc%20and%20sailing%202015/2015-03-27%2018.28.35.jpg.html)

bamamick
10-01-2015, 06:44 AM
I think it is very interesting that the same hull can be rated as a different class by changing the rig around some. Personally I have always favored the 30 squares because that rig looks right on that hull, but if you lived in a particularly blowy place you might want to rate it as a 22 square.

Mickey Lake