This is a very cool solution to the problem.
And it demonstrates how hams tinkering with radios is a good thing.
Looking in the ham radio catalog or the boat catalog would not have yielded this
solution.
Will take a cooperative radio shop to program it?
GE MPA or MRK will do it - both are type accepted as Marine radios, and cover the Ham band. The ONLY down side is they are NOT frequency flexible - in other words, you can ONLY go on the frequencies you pre-program. Usually NOT a problem, as I have every major repeater in my area, plus all the common simplex frequencies programmed too. One of my MRKs actually was USCG surplus