Another Small Problem (Resolved) - When I first reinstalled the gearboxes in the tank I noticed that they were not sitting perfectly flat on the mounting plate. The gearboxes would rock back and forth a little, but I couldn't find the problem. Later I removed the mounting plate itself to see what was underneath, and I discovered that it was the mounting plate that was not properly seated in the floor of the tank. I was warped - high in the middle. The reason was some protruding metal on the undersurface of the mounting plate (the metal that sticks out after drilling and tapping a thin sheet.) See the image below - these holes are tapped but unused on my tank, there are standoffs below the holes, and this is what the protruding metal is pushing on. I filed off the protrusions and now the mounting plate is perfectly flat and the gearboxes sit on the plate the way they should withought rocking.

I think that middle hole is supposed to be used, providing three mounting screws for the gearbox instead of two. The standoff below the middle hole is also threaded, but the holes don't line up with the holes in the mounting plate. Not sure if this is just a fluke on my tank or if all are like this. To use a middle screw I would need to either cut off the standoff, or maybe modify the holes in the mounting plate and gearbox so that the screw could go through the gearbox and the mounting plate to anchor into the hull itself. The later would be the best idea strengthwise.

Russ