[ShrimpBurrito]

The more I think about this, the more I like the idea of the vent pipe in the wall. Enter the wall of the bottom shell from the Sealand tank, then up the wall and exit to a flange on the exterior wall just below the top of the wall. That flange can then mate with another flange attached to an elbow protruding slightly below the bottom of the top shell. When the shell is raised, the connection is made. When the shell is closed, the flange in bottom shell is flush with the wall, and therefore does not interfere with the shells closing, and the flange coming out of the top shell simply protrudes maybe 2 inches below the bottom edge of the top shell, and so won’t cause any issues with road clearance.

It requires zero additional setup by the owner, should be robust, and should also provide a good seal when the flanges mate. Curious to hear what others think.

Dave