[ROSOBORONEXPORTCORP]

This idea is possible. Use 3d models from a patrol boat and the class file from a multi-gun floatplane. Adjust turret position, rotation and appearances and you can produce a generic gunboat.

I have tried using the MBR-2 and shooting up targets on the shore. It is a lot of fun (thanks to Oleg's ballistics model). The biggest (read only) problem is that it would require modifying the FM and DM.