With sufficient gas, take a bearing, descend to below prop depth (15-20 ft), and swim towing my SMB. If I have to surface swim, move lower boltsnaps from the belt o-rings to the door handles (have to do it anyway before boarding, but hard-linked tanks don't move as much on the surface), clip the upper bolt snaps to the rings. Swim on my back, and use my signal mirror to look over my shoulder to track the boat. I have a reg on a necklace, so it's easy to cope with occasional waves. When towing a SMB on the surface, I hook a 3 pounder on the line boltsnap, and let it trail.