"Diver" on this forum, who lives in Denmark, was kind enough to send me these pictures of a setup on his RIB. I haven't been able to track down a fabricator yet (the couple I have spoken to want to see the boat, which is buried under the snow at the moment), but it looks pretty solid. (Henrik, I hope you don't mind me posting these!)
The "hooks" reference is interesting and I also wondered if it was in reference to a disabled person. The guy I dive with most often is missing one hand and is a larger guy. Generally, he is able to kick himself up high enough (without tanks, weights) that I can haul him in the rest of the way. I keep threatening to use a gaff hook, but I think it might damage his drysuit! Alternatively, I was going to glue a SIB handle to his butt!