To Drain or Not to Drain...
Our boat came from the factory with the ice box draining into the bilge. Poor idea. The cold air in the box also flows down into the bilge; then the ice melts even faster. There is the additional problem of occasional food/beverage residue helping to cause the growth of "things that smell bad" in the bilge...
I kept a hose attached to the ice box drain fitting, and put a plastic ball valve at the end of it. Whenever the ice melt builds up a bit we pull the hose and valve out from under the galley sink area and drain the water into a pan and pour it down the sink (or, alternatively, boil it for rinse water for doing the dishes).
Our sink does drain to a thruhull with a seacock, directly under the sink. You sure would not want that "gray water" going into your bilge!
Loren in Portland, OR