vtec

David P. Martin (now independant-formally with ocean yachts is coming out with a book. A excerpt was in Professional Boatbuilder. Mostly empiracle stuff.

vtec

And me.

TopSpin80

and me I'm working in ANSYS now, but I do structures, so the flow is gonna be a WAG I'm only building 13 feet though and just for fun/research.... 13 foot with an old 50 evinrude I have in the garage.

Ernie

bcarpman

Thanks guys. I'll try to follow some of these leads, although many I have already seen and they didn't provide much of relevance for newer designs.

Ernie and VTEC, since you're building your own, care to elaborate on what you've found? From what I understand, even though you're building cats, the rest of it still applies. steps, etc. all work the same just with a lot of lift from the center section. Yes, no???

I think with Ernies small design, steps are probably not of benefit since the wetted surface area is so small anyway. What size is your design VTEC?

Thanks

vtec

48 ft or scale to 28 with some changes. pretty close to an existing design. Actually, I like to eventually make a 28 footer with a center pod and a jet drive with outragous horsepower.

For final tweeking I may hire an experienced crew chief/set up guy. For things like strake size and placement, and possible addition of sponson pads. Somebody whom has raced alot of catamarans.

But I may just build a wood model and be an armchair boat designer. If I were to build anything it would be mould-less construction.

The patents are good reading. check'em out. I really think boat design is a ton of trial and error -empiracle evolution, even though there are some good engineering analysis tools available.

I "heard"-on OSO- the alcone team(46 cut down skater) did some wind tunnel testing. Alot of the aero changes to a hull may hurt the appearance from a styling point of view, and also may not be pracital for everyday boating - a cut down transom comes to mind. For boats that are traveling above 80mph, the above the waterline features also become important.

I'm also an armchair race car junkie and alot of the same principles that apply to ground effect race cars can be related to catamarans - dynamic center of pressure related to center of gravity, ratio of intake to exhaust dimensions and the related velocity changes.

And the chapter in Principles of Yacht Design does read about stepped hulls.

We are all looking for the algorithm that outputs the worlds most optimized hull...............that's what makes the pursuit so fun.

vtec

And there's also alot to be gained from optimizing the skeg and prop combination. The skeg is the biggest piece of the pie in terms of drag.

Hydrocruiser

You just need 4 things...


Douglas Marine

Sterling Power

Arneson Drives

Miller Lite

iamfaster

Just call Reggie!!!

TopSpin80

CFD for free.... Nasa has some but I have not used it.. just found it today

http://tetruss.larc.nasa.gov/

need an Apple, of linux/unix Operating System.... I am thinking of starting up my linux machine.. haven't unpacked it since the move 6 months ago.

Ernie

Hydrocruiser

The man has incredible vision.