Is it a fact that a trimaran achieves three times the hull speed of a monohull boat of equal overall length?

Question

The hull speed of a boat depends on its length if it's a displacement boat.
Now, a trimaran has three hulls - does that triple the hull speed?
The water line is three times the length, isn't it?
Would love to be told whether this is true, because I want to build a boat, and displacement hulls are first choice for me, because I may go electric powertrain, but I need more speed than a monohull would give me.

Answer 1

Not true.

Hull speed only applies to displacement hulls and only indicates the most efficient speed. You can exceed hull speed but it requires a grunch of horsepower per knot of increased speed. That's because you've out run the displacement water and are now dragging a bunch of water trying to fill the hole behind you.

What a trimaran does is reduce the water plane area. But if you were to accumulate the water line length it is substantially longer.

Tri's are good for sailing as they are very stable. For power the tri advantage ends with the cathedral hull.

Smooth water you only need a planing hull. But when you get chop you need an effective cut through the wave. Cathedrals do that well and channel the water through the tunnel.

Answer 2

An electric boat seems the way of economy and simplicity. Yachts (catamarans) are being made that have two electric motors run off battery or generator. The generator is only one engine to maintain (fuel, etc) and has been claimed to use between 1/2 and a 1/4 of the petrol of a standard setup.

Answer 3

Not entirely. The speed of the hull really depends on it's wetted surface since that is the area that is causing the friction. A Catermaran (sp) style hull traps air which allows it to float more so than a comperable V style hull.

Answer 4

If you are that passionate about writing abouut football, go and start a football blog lol Writing essays on yahoo answers for nothing is a waste of time...

Answer 5

dream on.

Answer 6

NO!