Hi Daniel
Welcome
You have not specifically described this vessel but does it float or is it submersible. From the text is would seem to float but this is not explicit.
Maybe a device like this would work
This has a rotating mirror and looks to scan 270º. It may be able to be mounted on its side so it scans from water level one side, over the top to water level on the other side. The feasibility of this would depend on whether the rotating mirror can be operated in the horizontal position.
As for plan 2. You might be better off only using one unit and find a way to rotate it 180º back and forth like the above mentioned radar device.
As for the rest. I am afraid I will have to leave that to the digital gurus.
Cheers Bob
