not sure but I think the idea is to place engines in the centre of the mass. That would be closer to the WW hull on HP of course, raised and lowered in a box. Perhaps it is only to go forward one way and steer by rudders, never heard it come up so operationally its an important question.

You can get diesel outboards, but perhaps its better to have the same fuel as your gen-set if you have one, then its only one type of fuel to carry, and no accidents when crew top the tanks off. If you were really game, you could adapt an electric motor to an outboard leg and run off the gen-set. You would need a large generator though, or incorporate a battery supply.