Ground conductor on a boat lift

[sailingharry]

Some background first.
Our new house (almost 3 years now -- time flies!) came with a boatlift (a cantilever type with a huge steel track that goes down along a piling). The boatlift had one completely rotted track. I replaced it for several hundred dollars and a day's work. The manufacture (Magnum Boat Lifts) stated that this was caused by the plug not being removed after each use, and their instructions clearly state to unplug after each use.


I've just replaced the dock, have reinstalled the boat lift, and just rewired the dock.


The plug is a PIA, as it is hard to remember. It just got three times harder a PIA, because it now has an in-use cover.


So, I got to thinking. We boaters are very aware of galvanic corrosion instigated by stray currents on the ground wire (I don't want to get into a semantic/technical discussion on how badly I butchered those terms -- I don't see it as relevant). In fact, we install galvanic isolators to protect our precious metal parts from bad juju coming down our ground wire.


Under the NEC, a GFCI (breaker or outlet) provides such rock solid protection that you can legally install a 3 prong outlet on a 2-wire circuit (an old house, obviously) so that folks can plug in a grounded device and have all the protection that they think the 3 prong plug provides.


So.... after all that.... would it be prudent to replace my 3 prong cord to the boat lift with a 2-prong? I could then leave it plugged in 24/7. The GFCI breaker feeding the lift should provide better protection than the 3-prong plug. The in-use cover keeps all the plug stuff protected from the elements. And the lack of a ground keeps my lift from dissolving.


Could this equally apply to a boat? If I have a residual breaker (30ma) on my inlet line (I do), is there a solid reason (besides ABYC, which may be a little slow to respond to technology advances) to bring the ground aboard? I could in theory get a 30ma shock which is 6 times the limit for a GFCI breaker but still considered "moderately safe" (which is why they allow 30ma). I could improve this suggestion by adding GFCI outlets to the first outlet of each outlet circuit, making things like an A/C (I don't have one) or the hot water heater (or the breaker panel itself) as the only source of ground shocks over 5ma.


Two questions, I know. The boat lift one is the one I'm really interested in.