Too late for pics, but mine is as follows: The hull has a semi-circular hollow that cradles the tube through, oh, maybe 45 degrees of arc. The tube itself has a couple of flaps glued on (hypalon over some sort of heavy rubber; not sure what it is or exactly how it's attached.) The top flap is bolted to the hull (don't know if it's glued there or not. Never had reason to take it apart.) The bottom is secured with a strip of glued hypalon running the length of the tube, wide enough to extend an inch and a half or so onto bare aluminum, and onto the tube material on the other side.
Some boats bolt both the top and bottom. The leisure Zodiacs use a channel on the hull that accepts a strip of material with a bead on the end (the strip is attached to the tube, and slides on from the front of the boat.)