I'm sort of disagreeing with Roger here with his suggestion (I think)
of flexibly mounted engines but a rigid shaft coupling. On all the
vessels that we design, 95% use flexible mounts. We like Lo-Rez
because they are very soft (~0.5" static deflection). But to use them
you HAVE to have a flexible coupling because otherwise all that
vibration will get into the structure via the shaft and stuffing box.

Evan Gatehouse