Thickness of aluminum cat hulls?

If I am using type 5052 H32 Aluminium/magnesium alloy to build catamaran hulls, is .125 thickness adequate for a robust hull, assuming all curves, and bulkheads at a minimum of 5 feet on center? Also, can this material endure without coating it?

 

I wouldn't use less that 3/16 on a boat between 16' and 22' and wouldn't use less than 1/4 on the hull bottom on anything 23'-32'.How big is your boat? The material is fine without coating, it won't corrode away...ever...provoded that you use sacrificial zinc anodes. Theres a rule of thumb for zinc protection, I don't remember what it is. But only use engough zinc such that you have to replace it annually.

 

This is for my 50 foot x 20 foot (16 meter x 6 meter) solar electric catamaran that I am building. A company provides quite good looking and fair aluminum pontoons up to 60 feet long. Their calculations say the boat will go 10 MPH with 64 HP and the pontoons certainly have ample displacement for my needs. But are they durable enough for protected and inland water ways. At .125 thickness, dents and punctures could be a concern. Maybe there should be reinforcement below the waterline?

 

I wouldn't bother trying to put any kind of reenforcing on to these hulls. If they told you they'd work, hold them to it. If you're exceeding what they told you, I dunno what to tell ya

 

Should be durable enough, ya. The maker's engineered them to be, if he has any sense at all. They'll have a fair amount of internal structure already. And the curvature gives a lot of stiffness. Remember that aluminum boats out of .100 or thinner last for 40 years being banged over rocks and left upside down ont he dock over winter.