I debated where to put these. 
Criteria were:
1. Just above the water line to make clean out easier. (check)
2. Quick and easy access. (Check)
3. Close to each other so I could interchange them in an emergency. (Check)
4. Not in the way of other things...or me when moving in the engine room. (unknown)
5. Close to the engines. (check)

So I have set them up just inside the engine room.  You can access them from the hall way.  
One for the generator and one for the engine.

Above them is one of the wiring junction that will eventually go up to the pedestal.(anchor controls, GPS power, GPS NMEA wires.)