Welding Tips and Tricks

I am new to welding but someone has had a bright idea that I build a yacht out of Aluminium. The project is a 65ft cruising trimaran. This is planned to take about 6years to shell (fit out will be an ever ongoing - same as a house, once you finish, her indoors wants a change to decore). If your going to do a 14ft boat it will require the same skill, techniques and equipment for manufacture as a 65ft boat - so why not have what you want and not waste your money making 2 boats

The plan is for glass over ply which i am changing to Aluminium. Will be significantly lighter and cheaper to make. Less fairing time, no glass cost and price of aluminium is compareable to Ply of similar strengths.

The Ali sheet will be bonded to the frame/straiks using carbond/ metal bond and similar which will reduce welding time/costs.

The framing will be 50mm box section (6mm thick) - 6061grade
The straiks will be Angle ali 50mm x 25mm 4mmthick. 6061 grade
Skin and external fitting will be 5083 grade minimum 4mm thickness

The beams - still working on
The keel will be a mixture dependant on the region of the hull.

I need some advise for the following

1. The best technique including prep for seem welding 4mm marine grade aluminium sheet. I need to prevent warping and will be taking the welds back to a smooth finish so must have full penetration.


Any and all advise/comments are welcome.


I have the plans in paper form

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Wob