Above water thru hull fittings / valves

[Dalliance]

Living dangerously … my small boat has a total of 17 openings thru the hull (not including the rudder tube)! 7 are below the waterline, 6 are mid height above WL or close to deck joint, and 4 are just above WL. I have not looked at the 4 that are just above the WL at rest, but just below the WL when the boat is motoring or sailing. They have never been serviced or even checked AFAIK, except for the exhaust. I suspect that they may be a source of minor leakage while underway, so this winter I will be taking apart the whole stern area to look closely and probably replace at least the clamps. They are the exhaust, the bilge discharge and the 2 cockpit drains. The exhaust and bilge are looped. The cockpit drains are obviously not. It will be useless to put valves at the cockpit drains because it is impossible to reach them without taking apart the whole stern area bulkheads. This would be way to complicated for regular observance.

The other thru hulls above WL are 3 vents at the deck joint, an anchor locker drain, an ice chest drain next to the helm, and the vanity sink drain. The vanity sink drain is the only one above WL that has a plastic ball valve (that I have never closed). Obviously, all the below WL thru hulls have valves (Marelon), except the 3 'ducers.

I thought that sounded like a ridiculous number until I added up my through-hulls and realized I have 18 (including the rudder tube)! Seven below waterline, five at or near, and six well above or near the toe rail. There are ball valves on the intakes for the engine and the head, and on the lav and galley sink drains. The lav sink drain is at the waterline and the other three are below. I actually do close all of them when I leave the boat.
The only others that could take a ball valve are two cockpit scuppers but they are nearly impossible to reach and it would be counterproductive to ever leave those closed anyway.

 

[dlochner]

If the through-hull is in such a hard to reach place that the added ball valve shut off would rarely if ever be used,

If a boat was designed that way (and I owned one once) then we should drag the designer and builder down to the boat by their tonsils and make them service the valves or replace them!

 

[NYSail]

Gee, I wonder why I misunderstood?

and follow through with the next sentence... "considering changing configuration to reduce below water fittings and feel shut off valves are a good idea" as in I am moving them above water line......

 

[Scott T-Bird]

What would you be changing from below WL to above WL?

 

[NYSail]

My boat has 14 below the water line thru hulls.... And its a 2005 Beneteau which means the material used for valves is not as quality as it should be in my opinion..... I work my valves always..... close them every time I leave boat and open necessary ones when I am at boat and they all work perfectly with no leaking. I have eliminated 2 so far (removed and glassed over) with a basic re-configuring of front head systems and plan on removing 2 more this winter from aft head. Also will be removing eventually all valves and skin fittings to replace with Groco or Perko (or maybe composite) fittings.... One thing I have learned is just because the boat manufacturer made something a certain way does not mean I'm stuck with it. I would rather have less holes in the bottom and as such will be removing / glassing over then putting in new holes above water line. Some will remain but if I can get the 14 number down to say 8 I will be happy.

 

[NYSail]

What would you be changing from below WL to above WL?

Two Shower and 1 freezer drain discharge....

 

[Scott T-Bird]

So you eliminated the raw water intake and discharge from one toilet and will do it for the other as well. That seems odd, since you are coastal and have a large boat that would seem to be suitable for ocean passages. OTOH, if you commit to having completely closed systems for your toilets, I guess that makes sense. What else could you eliminate? I had 2 transducers for my Datamarine instruments. When I purchased the B&G instruments with just a single D-S-T transducer, I considered using one of the holes for the new transducer, but I didn't see any point in eliminating any systems that continued to work, and I like the redundancy, so I just drilled a new hole. I really don't understand the trepidation for thru-hulls. It's not like there is any significant pressure on these hulls at shallow depth - not enough to make the fittings a concern. I do close every valve when I leave because I agree that the hoses are the weak link.

 

[Scott T-Bird]

Two Shower and 1 freezer drain discharge....

I'd guess that your shower drains have to be pumped out? Is the drain below WL? Anything that needs to be pumped out, I would put above WL.

 

[Charlie Jones s/v Tehani]

If a boat was designed that way (and I owned one once) then we should drag the designer and builder down to the boat by their tonsils and make them service the valves or replace them!

LOL when I got Tehani, she had 7 openings below waterline. FOUR of those had 1/2 inch bronze pipes run right through the very bottom of the hull glassed in place Just straight pipes. No valves at all. Just the hose stuck on and a clamp. One was a sink drain, one was the ice box drain and the other two were the deck drains. ALL gone now.

 

[NYSail]

So you eliminated the raw water intake and discharge from one toilet and will do it for the other as well. That seems odd, since you are coastal and have a large boat that would seem to be suitable for ocean passages. OTOH, if you commit to having completely closed systems for your toilets, I guess that makes sense. What else could you eliminate? I had 2 transducers for my Datamarine instruments. When I purchased the B&G instruments with just a single D-S-T transducer, I considered using one of the holes for the new transducer, but I didn't see any point in eliminating any systems that continued to work, and I like the redundancy, so I just drilled a new hole. I really don't understand the trepidation for thru-hulls. It's not like there is any significant pressure on these hulls at shallow depth - not enough to make the fittings a concern. I do close every valve when I leave because I agree that the hoses are the weak link.

I don’t really fear the below water fitting as long as they are reliable.. it’s just beneteau put too many in and stuck them if tight places. I am removing toilet intakes (have fresh water flush) and also macerator discharge..... converted to gravity discharge and removed direct discharge / y valve. Lots of hoses for nothing.... beneteau likes to make simple things complicated..... you should see the electrical system!
Btw my count did not include transducers (2).

 

[Dalliance]

LOL when I got Tehani, she had 7 openings below waterline. FOUR of those had 1/2 inch bronze pipes run right through the very bottom of the hull glassed in place Just straight pipes. No valves at all. Just the hose stuck on and a clamp. One was a sink drain, one was the ice box drain and the other two were the deck drains. ALL gone now.

Hard to believe someone thought straight pipes glassed to the hull would be a suitable through-hull. It was smart to get rid of those.

 

[Dalliance]

Thinking about through-hull fittings, the one type that I am wary of is those white nylon ones. They become brittle with UV exposure and should never ever be used below the waterline or anywhere near it.

I think I have written about this before, but when I got Dalliance, the lav sink drain though-hull was that type and located right at the waterline, well below when heeled. I replaced it with with a bronze through-hull and ball valve. The bilge pump discharge was also white nylon, up high near the toe rail, but behind the electrical panel. Why I can’t imagine, but I doubt it was original. Anyway, I decided to relocate it to behind a galley cabinet and when I tried to pull the hose off the through-hull, the whole fitting sheered right off in my hand. That, to say the least, validated my decision about both of them.

 

[Jim26m]

I put a bilge pump in an unsinkable (full flotation) boat, because I would rather rescue myself than sit on a swamped boat waiting for help. I think you should move the through hulls to suit your comfort level, and add valves to any fittings that you feel might become submerged under even extreme conditions. Particularly, I'd move any with access issues as suggested in previous responses. Let's face it, after you've moved the through hull, adding a valve is almost insignificant effort and cost. If you get washed aground and laid over, you can keep her afloat, with your belongings dry, till the tow company arrives to pull you off (if it's on grass or sand...). You've done it before, so you know what it takes to fix the hull. I'd be tempted to use valves listed for through hull service.

Everyone has a different level of comfort. If I wasn't worried about a wife, kids, and grandkids, I would likely be thinking differently myself.

Your boat, your comfort level.