It's a rivited 1448, 0.060" hull.
I plan on putting a 4'x8'x0.125" 5052 on the bottom. I'm not sure on the best way to do it. I talked with a local shop and they want to cut the old bottom out. I don't see a reason to do that, other than it might save a bit on labor. I think that cutting the old bottom completly out would cause you to loose alot of structure that is already there.
Here are some pics of what I was thinking of doing.
Cut out the runners (represented by the black), grind the outside rivits flush with the bottom, weld the new bottom to the stringer (i think that's what you call it), weld the stringer to the origional bottom just because. Also put a weld from the new bottom to the old in the middle of the runners I removed (forgot to put that one in the picture) The welds are the grey areas (kinda hard to see).
On the back of the boat I was thinking of leaving the new bottom sticking out 3/8-1/2" and putting a 4-5" plate on the back of the transom the whole width of the boat.
I would drill a few holes in the stringers so water can get back to the bilge.
I am going to be using a MM210. What wire/size would you reccomend? Right now it is setup with .035 5356. Should I go with 4043?
I don't have much experience with welding aluminum, but I've been reading all I can find and practicing alot.
I think the hardest thing is going to be making that first cut! I do have another boat incase this one is in the shop for a while, lol.