For the past few weeks I've been struggling to think of some way for hamsub to dock with hampture and safely deliver hamsters to and from it. A docking collar was out of the question because it would require some kind of motorized system to pull the two docking rings tight against each other, motorized doors that would open, but also shut tightly enough to keep water out, and all of that would need to be radio controlled. It just wasn't feasible for me. Neither was an airlock system using doors, since hamsub requires an air tube. That's when this design occurred to me:
Fig. 1: Docking chamber with a moon pool in the bottom starts out full of water. This way hamsub can navigate up inside of it and come to rest on the part of the floor that wasn't cut away to make the moon pool.
Fig. 2: A separate air pump just for this one purpose is turned on, forcing air into the docking chamber, pushing the water out until the waterline has dropped down to the moon pool and the chamber is empty of water. The hamster is now free to climb out of the sub and up the tunnel into Hampture.
This is drastically simpler, doesn't risk catching the hamsters in the closing doors, and requires little in the way of modifications to hamsub. I am planning to make the docking station its own separate habitat, connected to the others by a long, flexible tube.
And no, the hamsub is in no danger of tipping over for the same reason a hot air balloon doesn't tip over; The very buoyant part is on top and the very heavy part is hung underneath it. This keeps it stably upright in water despite any attempt to tip it.