For the Design 2 build, I decided not to put the camera in the tub until I'd completed all the underwater tests (in an attempt to not break the camera this time). That done, I now needed to mount the camera. To do this I laser cut (I'm useless with a scalpel) two circular mounts out of card stock (designs are here: http://bit.ly/2drxVC4)

The camera is screwed into the center of the discs, the outer sits on the lip of the tube.

When the top is screwed back on, the camera is held in place.

Now back into the pool to make sure the the seals are still good.