I'm replacing all my old water lines and drain lines.I noticed that the drain line from the ice box and the sink under the companionway lead to a through hull,almost directly under the sink.It does't have a seacock on it so obviously I have to do something about this,should I remove the through hull(it looks like it has a butterfly valve),it is below the water line ,or just seal it,and redirect the drain line.If anybody has adressed this problem,it looks like it was factory installed(WOW it's 25 years old and still holding),I would appreciate any input. Thanks Jack Trip-J's Narragansett Bay,R.I.