The previous post was removed by the author since it doesn’t reflect an official position of the Formula 48 Class Owners Association.
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Note that the speed length ratio’s quoted in the above article are not NECESSARILY reflective of actual achievable multihull speeds; the old axiom for multihuls was 4 times the square root of the waterline length.But that really depends on beam to length ratio and other factors-such as is the boat using hydrofoils or hydrofoil assist…
The point I was trying to make is valid: using a shorter lenth hull for the ama must be looked at carefully and can result in less speed if the tri is designed to fly the main hull-much depends on the beam to length ratio of both hulls; a shorter hull can work with a higher beam to length ratio…
Thanks to Dick Lemke for posting the article and please direct any venom directly at him and questions to me…
Doug Lord
microsail.com
monofoiler.com
High Technology Sailing/Racing
Very informative piece, Doug. I wish I’d been aware of some of those factors when I built my 1m trimaran several years ago. Especially the part about ama buoyancy. It’s amazing how fast a submerged ama KILLS speed. Another design error was difficulty tacking, possibly due to insufficient rocker in the hulls. What comments do you have about this problem?
When I get around to trying another multihull, I hope to do a “Team Phillips” catamaran concept with twin rotating wingmast rigs. Right now I’m having alot of fun learning (from the rc plane guys) about spars vacuum bagged over foam, with skins made from glass, carbon or paper backed birch veneer.
Bill K
can somebody explained to me what “ama”? i dont build cat or tris but information is information
Cougar
Cougar, It is unfortunate that the information previously posted here was removed by Dick Lemke-it contained helpfull nformation regarding multihulls for beginners.
“Ama” is the politically correct(within the multihull fraternity) for “outside hull” particularly on a trimaran. “Aka” is the politically correct term for “cross arm”…
Doug Lord
–High Technology Sailing/Racing