Where not to put them is too low near the cockpit floor where water can get inside the boat, if they are the type where you are going to cut holes in the fiberglass, but Bavarias have open transoms, so a build up of water is pretty much not a concern. When you install anything (in this case speakers) you have to think of how you are going to run the wires from the stereo to the speakers, what you might be cutting in to when you make the holes for the speackers, where the speaker backs protrude, might get in the way in a locker, for instance and you also don't want to install them where the speakers will have a bad effect on compasses whether the binnacle or fluxgate, etc. You can also consider a pair that will mount on the stern railing on brackets making the speakers removable and so you can just make a hole for the speaker wires and run them through a waterproof deck outlet. There is railing hardware available that clamps on without drilling holes in the tube and then you can get creative on how to mount the speaker brackets to the rail mount hardware (Helm Ind is one source I can think of off the top of my head).
