Nice job and great documentation, but that's a lot of work, and the less holes in the bottom of my boat the better AFAIC!
As long as the water stays in the bilge, what harm does Ice do? Will it crack the bilge/hull? If so, Couldn't you simply have a space heater in the salon with a thermostat set at 40 degrees?
I know!...Treat your bilge to a pint of Bacardi's 151!