I just had a hull repair done and filled it with foam last night. West Marine has it, but you will overpay for it. I found it at Clark Craft in Tonawanda for a fraction of the price.
http://www.clarkcraft.com/cgi-supplies/ ... 37820a362d
I had pretty good results. They say optimum temperature is 80-90 degrees for application. I set the bottles next to a space heater to keep them warm so I didn't have to heat the entire shop. They say heating Part A in a microwave will work too, but I didn't like that idea.
Clark Craft sells measuring cups, you'll need at least 2 of them and a lot of disposable mixing containers. I used 12 oz plastic drinking cups. They say to use small amounts of Part A & B (2 oz each) and layer it in. I used 3-4 oz each in the 12 oz mixing cup and that is about all you'll fit. You'll need room in the cup for mixing and some expansion.
To mix it, I cut a paint mixing stick to 4", taped it to a wooden dowel and put it in a cordless drill. Pour Part B into your mixing cup, then Part A (Part A is the accelerator), and mix fast until it turns milky and starts to bubble. pour it into you cavity before it jumps out of the cup. It is pretty simple, but you have to work fast.
The small portions make it time consuming. I tried a few larger batches (5 oz each) to speed it up, but it is harder to control and I ended up with a few high spots that will have to be cut down.
Good luck!