[JohnB]

Truck tire inner tubes make a great lifting bags, and are easy to attach. Most boats when they go down, turtle, and are upside down. You will have to lift, and then flip it. I would use the lifting and bow eyes as attachement points.
Maybe put a tube on the front and on one side of the back to flip it, if it's upside down.

If it had a leak, you probably want to plug it. Once you get it near the surface, you could use 2 straps underneath it with tubes on each side to get the gunnels above the surface. If it is a stock cutout transom, you are going to have to work hard to get the back end "above water" before trying to pump it out. I have seen people try to tow swamped boats, and more often they roll over. Be careful if you have a line between the boats that you don't sink 2 trying to raise one.