Jay,
The retrieval system on the kits and as supplied as a fittings kit dates back to the late 60's early 70's when the boat was first kitted by Graupner, I think under a different name, but still the same ship, and had a polystyrene foam hull
The system works by having a long screw thread the length of the open compartment when the superstructure is removed. Attached to the screw system is just a length of wire with a loop on the end, that sticks out of the superstructure at the base of the funnel, The loop as far as I can remember is only needed for retrieval, launch is by gravity, when the tailgate drops. When lifting the daughter boat, it is steered into the drop door rear well, the wire with the loop on the end comes out and catches hold of the small bollard on the front deck of the daughter boat, which is then pulled up the ramp. The motion of the rear door closing should then push the daughter boat forwards and disconnect the loop, ready for the next launch.
Things have progressed a lot since then, and much more efficient designs for retrieval have been discovered, ranging from like a conveyor system that raises and lowers the daughter boat, to the use of a sail winch on a closed loop system. All much more compact and less intrusive into the main working compartment.
I found all these methods by trolling German web sites, just by searching for Adolph Bermphol. Unfortunately I sold my kit to a member on this site, and I think I gave him the web addresses with the info on. So if he is reading and doesn't mind showing who he is, he just might have the info already.
Hope this has helped.
John