technical q's for experienced welders

[tyrion]

Hi all,

Ive been asked to repair a few small cracks in an alluminium house boat while it is still in the water. My q's is , is this safe to do so? ive read on other forums there could possibly be some issues with your ground flowing out through the bottom of the hull or through weak spots, or even melting the anti foul off the bottom of the boat. Then others saying theve done it for years without problems. Ive done a fair bit of alli welding but never while the boat is in the water. Just after some additional info before i take it on. If anyone has done this before your input would be greatly appreciated. I would be using a tig welder on what ive been told is about 4-5mm alluminium so 100 -120 amps there abouts.