I see you have 85 Yamaha motors on your diagram. Do you have these motors already?
If not I would strongly suggest you look at other motors, preferably 4 strokes.
The Yammies are very reliable, I know, but they use so much fuel(totally unnecessary), it will be a challenge when going over borders or far from filling stations to fish, and quench those motors' thirst!
Good luck with your project!