Excavator engine in a boat?

Long shafts

The same boat had 22' shafts inside plus some exposed. There was a flex coupling right behind the engine and one at the rear before the shaft went through the hull with a support bearing. Once every thing was in line, there was very little vibration with the twin 300hp cats at medium power settings. It was also very reliable- the boat went around the world plus a lot of cruising under power. My usual cabin was over the rear of the starboard shaft so I had a very personal interest in it. Bruce