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YachtForums · 07-14-2005, 09:20 PM

I read the article in Yachts too, but it really didn't answer many questions. For example...

1. There's no doubt that White Rabbit (and the trimaran concept) is inherently stabile, both at speed and at rest. This configuration is further enhanced with an active foil system. According to the Y.I. article, it's a VT Maritime Dynamics system and there are four foils, each with 50 sq. ft. of surface area. It's pretty safe to assume they're using horizontal foils that span the distance between the center hull section and the sponsons (two on each side, fore & aft). Between this stabilization and the narrow cross section of the center hull and sponsons, I'd have to expect a dramatic decrease in pitch and roll momentum.

2. Before I looked at the article, I kept wondering about its engine room config. Obviously the propulsion systems aren't located in the outriggers! BUT... the center section is SO narrow, it had me wondering. According to the specs, the engines are staggered, front to rear. Clearly, there isn't enough space for the engines to placed side-by-side. Although this is rather unconventional for a yacht, it's actually a GOOD thing, because it further enhances stability. Quite simply, it keeps the engine weight closer to the longitudinal centerline of the hull.

3. The article tends to emphasize the above deck space. Probably with good reason... White Rabbit has a 50 foot beam! But of course, they didn't say much about below deck space. I think it's reasonable to assume, given this hull configuration... the below deck space won't match a comparable a mono-hull.

4. This hull has many benefits, BUT... I have to wonder how maneuverable it is? I understand it has a fixed bow thruster and a deployable stern thruster. I would imagine this was mandatory, because there is very little space between the props to create any leverage against the hull for maneuvering/pivoting AND you've got two rather large outriggers that are effectively acting like long rudders. This would create an opposing force against turning.

5. The article also indicated that wave slap was considerable reduced. I can understand this, due to the sharp bow entry and the narrow cross section of the center hull and outriggers, BUT... in my experience, wave slap can become more pronounced when water CAN'T be displaced and is forced to travel under exposed sections of an inner hull. In studying the pics of White Wabbit (

) it's clear the tunnels have sufficient vertical height to allow most wave-chop to pass uneventfully. But when the seas get big... I dunno!

Wisdom is welcome!

07-14-2005, 09:20 PM	#8
YachtForums Publisher/Administrator Join Date: Dec 2002 Location: South Florida Posts: 10,227	I read the article in Yachts too, but it really didn't answer many questions. For example... 1. There's no doubt that White Rabbit (and the trimaran concept) is inherently stabile, both at speed and at rest. This configuration is further enhanced with an active foil system. According to the Y.I. article, it's a VT Maritime Dynamics system and there are four foils, each with 50 sq. ft. of surface area. It's pretty safe to assume they're using horizontal foils that span the distance between the center hull section and the sponsons (two on each side, fore & aft). Between this stabilization and the narrow cross section of the center hull and sponsons, I'd have to expect a dramatic decrease in pitch and roll momentum. 2. Before I looked at the article, I kept wondering about its engine room config. Obviously the propulsion systems aren't located in the outriggers! BUT... the center section is SO narrow, it had me wondering. According to the specs, the engines are staggered, front to rear. Clearly, there isn't enough space for the engines to placed side-by-side. Although this is rather unconventional for a yacht, it's actually a GOOD thing, because it further enhances stability. Quite simply, it keeps the engine weight closer to the longitudinal centerline of the hull. 3. The article tends to emphasize the above deck space. Probably with good reason... White Rabbit has a 50 foot beam! But of course, they didn't say much about below deck space. I think it's reasonable to assume, given this hull configuration... the below deck space won't match a comparable a mono-hull. 4. This hull has many benefits, BUT... I have to wonder how maneuverable it is? I understand it has a fixed bow thruster and a deployable stern thruster. I would imagine this was mandatory, because there is very little space between the props to create any leverage against the hull for maneuvering/pivoting AND you've got two rather large outriggers that are effectively acting like long rudders. This would create an opposing force against turning. 5. The article also indicated that wave slap was considerable reduced. I can understand this, due to the sharp bow entry and the narrow cross section of the center hull and outriggers, BUT... in my experience, wave slap can become more pronounced when water CAN'T be displaced and is forced to travel under exposed sections of an inner hull. In studying the pics of White Wabbit ( ) it's clear the tunnels have sufficient vertical height to allow most wave-chop to pass uneventfully. But when the seas get big... I dunno! Wisdom is welcome!