Butted Hull Sheeting

[jprevj]

Maybe I should rephrase the question. Does anyone have any information on how often a builder, either custom or semi custom will butt aluminum hull plating of 1/8" to 3/16" 5052? Do most use hull plating of continuious aluminum or do some, all, a minorty butt sheets of 8', 10' or 12' to make the full lenght. If some builders butt how do they address the weld? Leave it alone? Grind, feather and paint?

I have a design I would like to build and have priced coils of aluminum, 5000 lb minimum, and I can't justify that. I've read here about how to well butts, but are butt welds accepted practice on boats under 18' or do most production builders use coil for the time savings?

[alidesigner]

It depends on size as you are limited by sheet lengths but under 8m most are built from one piece. People tend to avoid joins to minimise distortion. The trick is to force some slight compound curvature into the shape to minimise buckling.

If the hull is designed properly you can get a great finish, if not you can get a buckled mess.

Wouldn´t a 5083 or 5086 be the better choice?

And the one sheet hint is a very sensible one, though I see the main advantage in the spared welds. Less HAZ, homogenous material.

[alidesigner]

Most builders will avoid joins when ever they can. They take time and cause distortion. The ones that do will sand and bog over before painting, although sanding welds off is not good practise. You should be using 5083 for marine and you should be able to buy it by the sheet.

So in summary for boats under 18' it would be rare for a builder to join small sheets. It would also be rare for them to hold much stock of plate as they just buy in what they need and keep any off cuts. Shop around for a different ali supplier.

To use a single plate you do need to make sure that the hull shape is developable otherwise it wont pull up properly and the internals will have gaps or will need trimming.

Hope that helps.

[jprevj]

Thanks for the responses. Very helpful.