Comments on: Jim Brown & Andy Zimmerman Talk Hydrofoils on Small Trimarans http://smalltrimarans.com/blog/?p=8040 The first online community for enthusiasts of trailerable (and cartopable) trimarans Tue, 21 May 2013 01:18:27 +0000 hourly 1 By: Fred Goldfarb http://smalltrimarans.com/blog/?p=8040&cpage=1#comment-9871 Fred Goldfarb Mon, 28 May 2012 12:05:09 +0000 http://smalltrimarans.com/blog/?p=8040#comment-9871 While in college I had a course on some hydro/aero related subject. I was able to get the professor let me do for a final project (instead of answering a number of difficult problems) a set of hydroils for a small sailing trimaran (my Brown 25 Searunner in fact)! I got an A on that and I think an A in the course. The foils were simple “ogival” section (flat on one side, steady curve on the other, like a section from a circle extruded). However, they were curved to go under each ama with the curve going inboard, and and flat section facing away from the vessel. Net effect would be to both lift and stabilize the boat. I never got to actually build and test them, but my professor thought it was a pretty cool final project design. Somewhere in my files I still have that paper, sketches, calculations, etc.

When I worked in naval architecture we worked (including me) a hydrofoil patrol craft for israel. Used 3 inverted “T” foils and gas turbines (jet engines) for power. Unclassified speeds were 28 knots in displacement mode and 70 knots flying. Top speed flying was probably really closer to 100 knots, but that’s just my educated guess.

I’ve always wished David Keipers’ work was continued, since he crossed the Pacific in a 31′ hydrofoil trimaran (Williwaw).

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