Six shafts on a narrow ship

Certainly this is a pretty outrageous thing to contemplate, but I find a compelling desire to find a way to have six shafts and engines. My approach is to use very light, high power per weight machinery, which implies smaller machinery, and to have a destroyer-like shafting, where the shafts angle down from the horizontal. It may be a bad idea, but I would also angle them out, very slightly. That would certainly reduce their efficiency, in that the main thrust would not be on the centerline of the ship, which is the most desirable arrangement. I would also crowd the shafts together so that there might be some undesirable turbulence between propellors and adjacent shafting. I would either have a round, destroyer-like stern or else would actually go to a wide transom. A wide transom would have some beneficial effects at high speed, although it would also increase drag at lower speeds.