Sea Pearl Tri 21

[bfrowe]

When I posted my leeboard question, I was gratified by the non-judgemental responses and suggestions I received. When I responded to the Small Trimaran question, I guess I took it off thread somewhat talking about amas and such. Sorry.
My goal with my small tri is to improve its basic systems. Lorsail has intrigued me with his reference to a Bruce foil. Sea Pearls have flat bottoms stem to stern and I know of one tri that does 8 mph in 10, 10-11 in 15 and over 15 in 20 mph winds. Broad reaches. I forgot that I had this info in my files. If a Bruce foil can help keep the boat flat or add a little lift-a la hydrovisions, maybe we can improve windward performance too.
Bruce

Bruce when you sail in the conditions you mentioned in your post can you describe the amount of immersion of your ama in those same conditions when the boat is sailed at it's fastest?

[bfrowe]

Close reach: about a third, broad reach: 10% or so. 10 mph wind
Bruce

Bruce, I ws hoping Tom Speer would jump in here as he could give you excellent advice on the foil. It appears he may be helping you on foils.org and thats good.
I'm not entirely convinced the foil is suitable but it may be.
Keep in mind that you could have two foils -one on each side-designed so that they're both not in the water at the same time which would allow asymetric foils.

[bfrowe]

If I used the foil, I might be able to get away with an ama with less volume/weight-say an old Hobie 14 hull (more rocker) and mount the foil on a seperate strut that would rotate out of the water on tacks, in shallow water or in light air.

A fourteen hull sounds like a good idea. How would you rotate the foil?

[bfrowe]

Depends on how much force we are talking about. If I keep the leeboards, then the foil wouldn't have to be 40% larger than them, I don't think Tom considered two foils in his answer. I could mount the foil on a crossbeam between the two amas. It could be on a swivel like a trailer jack with holes drilled for deployed and retracted. It could be mounted securely to the beam and then the beam could be twisted up and down. Or I could ask others for advice.
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Bruce Rowe