Re: anyone ever own this? i got questions
If you have fresh/salt on the sink you have a fresh water tank somewhere, which needs its own pumps and hoses.
Don't use a "fish box" that drains into the bilge for fish unless you want a stanky bilge. OK for a drink cooler, although probably not well insulated.
Keep in mind that with an oold boat, there's no telling what the previous owners rigged up. For example, they may have added that sink without having a fresh water system.