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  #46  
Old 04-17-2010, 05:38 PM
frank smith frank smith is offline
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Quote:
Originally Posted by tom28571 View Post
I'm not a fan of the rudder taking a lot of the lateral resistance. I once broke a rudder off in strong wind just off Royal Shoal on the way to Okrakoke. If there had been a heavily loaded rudder like on St Valerie, I would not have been able to steer well enough to get the boat into harbor without auxiliary power.
It worked for a few thousand years for the Chinese, but it must be a new idea to you .
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  #47  
Old 04-17-2010, 06:14 PM
Bill PKS Bill PKS is offline
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Two-fer.

Fellows,
There was a 30' <> 40' boat I saw a long time ago that had 2 boards.
A larger board forward, and a smaller way aft.
( I don't remember the name or the builder.)
The forward board was let all the way down, the aft board was used to balance CLR, and the rudder to trim.
While a really fine idea for cruising, it seems to me it would be counterproductive for any speed.
Boards , keels, fins or what ever rapidly increase wetted surface ( drag) .
Less appendage surface submerged the better, providing you have the desired directional stability for the desired use.
Much easier to move CLE, with rigging .
( See the comment on the Polynesian Cat at post 9.)

Tom, The Belhaven is very nice. ( My sister-in-law's family had a cottage up at Belhaven.) I have owned San Juan 21's ( A Bermuda Sloop). We had a fleet of 15 or 20 around here in the late 70's . A friend bought the molds from the the Clarks back in the '80, and built 30 or 40. I thought the problem with the SJ 21 was the soft chine. With board pinned up, I could turn mine on its side by swinging out on the halyard quite easily. The hull depended mostly on +500# CB for stability.
Although I could get it to Surf on a reach while jumping waves in Beaufort Inlet ( providing we had enough grog), I was always looking for, but never found, a low rocker Hard chine 20' something RFG boat to see if I could get it to plane out.
When (unofficial) racing the SJ, I would kick up the rudder,and then the board as much as possible and use sail trim and weight to steer. Absolute minimum use of rudder ( drag). Surprising how much difference that made.
With a lower house, and Sloop rig, the Belhaven hull form would be very interesting.... although, it might have a bit more rocker than I would like to try.
(For now, I'm looking at a 14' foot skiff for grandson, and 44' Schooner for me.) Cogitations about those hulls are what started this thread.)
By the way, I've got 3 or 4 of the iI-14's sold. Not enough for any production; and, I can't put in the time to build 'em right now.

Messabout,,
Absolutely right. Either the bow pushes water aside, or down ... or the water piles up.
Seems to me a Fine entry at the forefoot to slice thru the seas > More fullness higher to ride up> flowing to longest lowest rocker possible while getting buoyancy for the weight... with the objective to sail on top of the seas not swim thru them. Then, as you suggest, cut off the stern to aerate the wake and further diminish pulling up a stern wave.

Bill PKS.
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  #48  
Old 04-17-2010, 07:22 PM
tom28571 tom28571 is offline
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Originally Posted by frank smith View Post
It worked for a few thousand years for the Chinese, but it must be a new idea to you .
Chinese junks were generally balanced by inserting daggerboards to different depths fore and aft in the hulls. To the best of my knowledge they did not depend on rudders to balance lateral resistance. Such an idea on their large ships would probably have been unworkable. Not my specialty so I could be wrong but my opinion of the heavily loaded rudder stands intact.
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