The Hatch

Docking is a hard problem to solve at pressures that we have to deal with at the habitat's depth. Most deep sea submersibles do not have to worry about docking because they commute up and down from the surface. We have to look for a way to dock with the habitat. We have decided to employ both internal and external docking mechanisms. Usually, the submarine would dock on the outside of the habitat's docking sphere. However, if it needs to enter the sphere for any reason (e.g. if it needs to be repaired), it will be moved into the docking sphere. The mechanism of internal docking has been left to the habitat designers to develop given the dimensions of our submarine. However, we are responsible for the external docking design.

We came up with a design that uses the pressure difference between inside and outside of the habitat to keep water from coming in. It works almost like a mini airlock between the submarine and the inside of the habitat. Below are two views of the docking station that will be part of the habitat.

The top picture is from the outside looking in. The bottom picture is a cross section. The blue disc is the door that opens outward. That way the water pressure will keep it closed, and keep it from leaking. The little brown assembly is the hinge. Beyond the door, there is the docking sphere of the habitat. It is not shown, but there is a little release valve in the door and another release valve on the side of the wide part of the dock.

Below is the hatch, which is the part on the submarine that fits into the dock.

The top picture is from the outside and the bottom picture is a cross section. The hatch is attached to the top of the submarine, but for simplicity the submarine isn't shown in the pictures. This door also opens outwards, so the water pressure keeps it closed. When the submarine is docking the hatch fits into the docking station snugly so the top of the hatch is flush with the lip inside the docking station. Then the water pressure is very slowly released so the sub hatch gets pulled into the dock by the pressure difference with several tons of force. That makes sure the seal between the top of the hatch and the dock lip will stay tight. There will probably be a hard rubber gasket to improve the seal. Once the pressure is released between the two doors, they can open both the doors and the submarine is docked as shown below.

An animation of this docking mechanism will soon be put up on the page to aid the visualization of the docking mechanism.