The answers are simple, yet seem too obscure for those great naval architect minds... The bridge clearance to the water line needs to be 40 inches... There must be adequate hull ahead of the leading edge of the bridge to lift the bridge over the incoming wave... And, the tunnel cannot get smaller as the wave travels aft (water is not compressible... Look at the tunnels on many production cats, PDQ comes to mind, jeez...) The specs for the cat I am having built is coming together and meets these specifications... There is 10 feet of hull projecting ahead of the bridge, i.e. pickle fork... There is nothing in this center area, no trampoline, etc. for the wave crest to impact against... And the hull form looks like a monohull with a flared bow to turn the wave crest aside... Once architects get it in their heads that they cannot cover the hulls with the Waldorf Astoria Ballroom ( it's not a pontoon boat) and that the boat has to be light (no 3 pounds to the square foot of solid fiberglass) cats will gain favor due to their performance advantages... denny ---------------------------------------------- Mailblocks - A Better Way to Do Email http://about.mailblocks.com/info