Re: patching up a tube
Well, yes but how do plan on getting to a leak with the boat in the water?
You can use JB Weld and it will hold almost as good as a weld but you have to be able to get to the leak first.
I would also leak check the tubes, alot of time a leak is more than one, especially if the boat is older you will get cracks at the edges of the brackets from stress.