Add to this a sound shield and the space required becomes a vital concern for placement of the unit. Weight also will have a direct bearing on placement. If the unit cannot be placed on the centerline of the boat, the weight factor is even more critical. Whereas placing it too far forward will create a bow-heavy boat, too far aft will force the boat to squat in the water when under way. Living aboard and cruising require different considerations than those of a weekend boat.
Noise characteristics are another important question.
The decibel level with and without a sound shield should be investigated because it's not uncommon for space limitations to rule out a sound shield around the generator. The unit must have easy access to check the oil and coolant levels and to change the water-pump impeller, fuel filter, oil and oil filter. This access must be equally easy with and without the sound shield in place. If the sound shield must be completely removed to accomplish any of the above, the projects will most likely not be completed on a regular basis. He can help calculate the correct output, physical size, cooling and exhaust requirements.