I have g 3 1648 job boat , I found a crack in the middle of my boat that's leaking water , not to bad but I need to fix it. I looked on YouTube and saw a video on super allow 5 , and other aluminum flex less rods from harbor frieght, which is the best way to repair it ? Thanks

I have used brazing rods on leaking rivets, but a crack that is leaking I would weld.

I used to weld aluminum quite a bit with a TIG welder or an acetylene torch with flux rods. It was very tricky to do.

I had a couple of cracks along a weld on a small aluminum boat a couple of years ago. I used some of the new aluminum welding rods with a MEP gas torch to weld them up. These welding rods are a lot easier to use than the old flux aluminum rods. The new alloy rods don't require as much heat and are supposed to be very strong.

You will want to go to a welding supp[y & invest in some good blue goggles. These will let you see when the aluminum is getting too hot & starting to sweat. Get some light scrap aluminum & practice some welds before starting on your boat. Brush along the seams with a stainless steel brush until you have removed any contaminants or oxidation.

My other advice is to find someone that welds aluminum regularly. It's really easy to melt a hole through your boat if you're not sure what you are doing.

Great True Advice all I ask is can you get to it from inside and can you flipboat easily (welding on back is another challenge)..If you go do it yourself route Get a new SS brush and use it for aluminum only
FERGY last statement is so true

If you have to ask what to use, you shouldn't be welding on your boat.
A man's gotta know his limitations. Find an experienced tig/mig welder. Do it once, do it right.