1st of all you're paying waaaay too much for ice. I pay $5.50 for a 186 quart igloo full (a little more than two totes). If you don't get a machine you need a new supplier.
I would not put a restaurant type of machine on a boat, the constant humidity and occasional salt water will do in the icemaker. I've seen it happen at marinas. If you really want to get one, keep it at home in the garage or someplace out of the weather.