We are starting the building process for Levitation... She is a 50' X
26' trawler power cat... The bridge clearance is 3 feet at full load..
Part of the design process was looking at issues such as stability and
pounding... The solution (we believe) is adequate bridge clearance,
keeping the ends of the hulls uncovered by the bridge, and more beam
than the popular factory designs..
The advantage of having 3 feet of bridge clearance at full load is
intuitive and no deep analysis is needed... The increased dock height
is handled by either med mooring or by opening the boarding gate on the
dock side and using a dock step....
More beam gives you two things immediately...
The first is the increased hull separation dramatically dampens the
inner bow waves from ramming each other and slapping up against the
bridge... The second is that stability is increased significantly if
caught beam on by a rogue wave...
The final part of the equation is that there is unburdened hull both
fore and aft - with generous bulworks... Commercial cat designs inflate
the bridgedeck until it covers every foot of hull and what you are left
with is a pontoon boat with a condo on top... What I did was design a
35 foot bridgedeck cat and put it on 50 foot hulls... The ends of the
hulls are not covered by deck, can plunge into the wave just like a
monohull, until the increased flotation lifts the bow (stern) and there
is no horizontal surface near the hull ends for the exploding wave to
slap against.. ..

Most commercial boat designs are aimed at looking good at the dock, and
everything else is secondary... Ya gotta march to a different drummer
if you think for yourself..

denny