Power Trimaran

[BayouDude]

I am taking a course at the University of New Orleans and am going to design a power trimaran. I would like to do something about 80-100 foot with a 20-30ft beam, a range of 1000 miles and a cruising speed of 20kts. I was thinking the vessel would be used for a live aboard dive boat or possibly a yacht. I was intrigued by the trimaran hull and was wondering if anyone had any suggestions? Any input would be appreciated.

[fcfc]

You should look at Nigel Irens designs.

[D'ARTOIS]

What might be your motivation to choose for the power tri concept? Any mono would feed with ease your bill of requirements. The power tri, in its true concept, is just to achieve speeds normally unobtainable by monohulls. If you are looking for the wide-bodied designs you better go for the cat design.
I play a bit around with tri-designs, actually winged monohulls, to go fast, stable and with a minimum of draft that allows you to enter shallow waters. Beachable too.

[doesitfloat]

I did some work a few years ago with a concerp of a tri Patrol boat. There was a large gain in deck work area however the seakeeping limited it's operation. If it's a fair weather fun boat probably work out just fine.

[BayouDude]

Thanks for the input. I have just taken a look at some of Nigel Irens designs and they are impressive. I have decided on the trimaran because the class focuses on cats, tris and surface effect ships. Most of my experience is in tugs and offshore supply vessels so this high speed stuff is somewhat new. I would prefer to do something other than a monohull even though the benefits offered by a trimaran for this size and speed may not be exceptional.

[kach22i]

Originally Posted by BayouDude

cats, tris and surface effect ships.

I own a small hovercraft and have notice that Sevtec hovercraft kind of function like a catamaran- but not exactly.

This got me to thinking if there was any tri-pontoon type surface effect ships.

I know that the solid sidewall wall cushion vehicles are a form of non-displacement cat, in a gray area way.

If the hovercraft bag side skirt is made to be of such high pressure that it acts as a inflatable pontoon - or RIB (rigid inflatable boat), then it would act like one, right?

The wave impact on a RIB is turned into mechanical energy by the air-spring effect which then allows for higher speeds, right? So even a non-displacement hovercraft should be able to deflect more of the wave energy impact, or so it follows to think so.

What would a tri-pontoon type surface effect ship really look like?

Actually I have drawings and built a non-working model. Just trying for a little feed back before I post it or do more work on it.

If this concept has been explored or dicsucssed before, please suggest or provide a link. Cheers all.

Note - cool link:
http://www.nigelirens.demon.co.uk/index2.htm

[mackid068]

Throw on some drawings please!

[FAST FRED]

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[D'ARTOIS]

Caveat Emptor........

[boby boy]

I believe a trimaran is a wonderfull choice, a multi hull boat was my first creation. just some advise fom a previouse design of mine: if you are gouing to have a center board instead of a fixed keel it is very conveniant to run it through a table below deck. this way it gives the table added suport and keeps it out of your way

[boatgm]

i just started building a power tri will keep you'll updated

[brian eiland]

Originally Posted by BayouDude

I am taking a course at the University of New Orleans and am going to design a power trimaran. I would like to do something about 80-100 foot with a 20-30ft beam, a range of 1000 miles and a cruising speed of 20kts. I was thinking the vessel would be used for a live aboard dive boat or possibly a yacht. I was intrigued by the trimaran hull and was wondering if anyone had any suggestions? Any input would be appreciated.

I assume you are familar with this recently launched tri-hull vessel http://www.yachtforums.com/forums/sh...6&postcount=26

[kach22i]

From brian eiland's second link:


http://www.naval-technology.com/projects/trimaran/

ADVANTAGES OF TRIMARAN DESIGN

The advantages of a trimaran hullform over conventional mono-hulls are thought to be: reduced costs, reduced signature, significantly less drag increased speed, increased length, giving greater stability, and more room for the upper deck, which could be used for the flight deck as well as hangars for helicopters and extra armaments.

Reduced cost?

I'm not sure building three hulls is cheaper than one larger hull. However I agree with the rest of it for the most part.

What happends when a surface to surface radar beam hits the main hull and bounces back and forth inside/against of the smaller outboard hull? Does it get trapped or sent back to the sender giving away the location?

[marshmat]

Radar signature depends very much on the shape and material of that hull. 90-degree angles are very good radar reflectors; stealth aircraft usually use a lot of 48-degree angles to minimize signature. Metals generally reflect more than composites. The shape of a boat is so complex that it's hard to predict radar signature without an actual test range. Having said that, if you suspect your vessel's radar signature is small (often the case with thin composite-hulled boats) it is prudent to hoist a reflector.

[kach22i]

Reduced cost......could of meant "reduced operating cost".

That is to say for faster speeds it consumes less fuel - I guess.

48-degree angles to minimize signature

I'm thinking because the water surface is a large reflective plane, things could be different for boats than airplanes.

I've noticed all the current and future watercraft designs are stealth, patrol boats, Corvettes, Destroyers and so forth are all clean deck flat plane designs - not much more than 10 degrees (in lieu of 48 degrees).