Thru-hull advice

[Tim Mertinooke]

Need some advice. My boat was originally outfitted with three thru-hulls that were at the waterline. One was for the bilge pump, and the other two were for deck drains and none had seacocks, only bronze mushrooms with associated retaining nuts. Last season I ran into some issues with my bilge pump creating a siphon after it finished emptying the bilge. This process would happen over and over and it took me a while to even realize it was happening. There was a one-way valve fitted by the previous owner in-line with the pump, but apparently it was not doing its job. I decided that I would (with proper technique of course) fill the bilge pump hole and move it to the transom, placed above the waterline so that there was no chance of siphoning. I filled the bilge pump hole this past weekend successfully and was contemplating raising the deck drains above the waterline as well if only so that I could re-use the nice fittings that were there originally and not have to mount seacocks. Would a deck drain at the waterline need a true seacock or could I re-use the fitting where the hole exists now like it was originally setup. Should I raise it a foot or so?

The bronze fitting for the deck drain

[Hirilondë]

.......was contemplating raising the deck drains above the waterline .......

I don't know what kind of boat you have, but your cockpit sole is most likely not very far above the water. If you raise the drain outlets you may find your cockpit doesn't drain very well.

[Tim]

I'm assuming by "deck drain" that you mean something like a sidedeck drain rather than a cockpit drain.

If your outlet is truly clear and above the waterline, I don't think you need a sea valve. Deck drains are one of those things that you wouldn't tend to ever shut off when leaving the boat anyway. Valves are always a good idea for emergency situations, but it'd be unusual to see one in this sort of typical deck drain situation.

If it's "at" the waterline, I might change my opinion. In general, I prefer to avoid fittings in this gray area--either mount them well above the waterline, or else treat it as you would any below-waterline fitting.

Is there another place you can lead these deck drains that could tie into an existing fitting elsewhere, such as conjoining with the cockpit drains or some such? Through hulls in the middle of the topsides are not too attractive and I think I'd be looking for alternatives before I relocated the one you show somewhere higher than the boottop.

[Tim Mertinooke]

They are sidedeck drains as Tim surmised. Adding them to the existing cockpit drains sounds like a good idea and I think I'll go that route. Thanks!!

[Ric in Richmond]

What do you all think of the fiberglass tube drains that are indemic to pearson products ? I have 4 of them, all are very solid, but freak me out. No valves. They do end at what appears to be a point above the water line.

The side deck drains on mine are fiberglass half round tubes that are laminated into the hull and these do NOT freak me out...should they?

Back on topic I have a bronze thru hull that is fractions of an inch above the waterline with no valve. It "should" never pose a problem, but it freaks me out as well. Next time she is out of the water she is getting a seacock there.

[Tim]

I think the general rule ought to be that if you are freaked out, add proper fittings and valves.

Specifically, I am not a fan of the Pearson fiberglass tubes and replace them with sea valves and through hull fittings as a matter of course.

The half-round deck drain tubes are fine as long as they are fine. (i.e. if they are sound and waterproof)