I needed better access to lots of items in this area of the engine including the water pump, engine starter, water heater, wiring. So I cut out a large enough opening(a 6 gallon water heater will go through here) and then built a "sink board" to fit the cut out. In that, I under-mounted my old sink. You just loosen the drain tailpiece on the sink basket, and that's it(you could add a positive lock below but we don't do 360's ever on our boat).

It's seen over 10 years of heavy use. I oil the fir(flooring actually)every couple years, which we cut directly on. That's my daughter kneading bread dough on it more than 10 years ago. Looks the same today.