waves on pontoon structure

[Hisham]

I am designing a pontoon, the left side hull and right side hull will be connected to gather at the stern with a transverse steel bars or truss
I know that in mono hull ship, the critical waves stress is sagging and hogging
So where can I fiend a good description of wave stress act on pontoon or catamaran

[KCook]

As a practical matter, on small (24 foot) recreational pontoons, the main trouble is twist. One side rises for a wave out of sync with the other side. Sorry, don't know of any studies quantifying this.

Kelly Cook

[sharpii2]

Originally Posted by Hisham

I am designing a pontoon, the left side hull and right side hull will be connected to gather at the stern with a transverse steel bars or truss
I know that in mono hull ship, the critical waves stress is sagging and hogging
So where can I fiend a good description of wave stress act on pontoon or catamaran

I would make some kind of allowance for flexing. The port hull may be climbing up a wave whie th starbord hull may be coming down one. With steel connecting beams, I would use some kind of compressable bushing under the connecting beams. Otherwise, I would have to worry about metal fatigue at the connecting joints.

Either that or I would make the structure so rigid that it would hardly flex at all. This could be done with a large, thick box beam in the form of a wing deck.

In a matter like this, experience is everything.

Bob

[ted655]

A truss will not flex. A better design would be a torhsion bar. Or a walking truss, hinged in the middle, but under a type of tension by some device (spring?) to return the truss to normal surface rigidity.