Thru hulls

M

mx8

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I have a couple of thru hulls leaking in my boat, not much, just a weep around the nut.. I plan to remove and rebed them at haul out in a month or so. The problem is it`s driving me nuts and I want to put a wrench on the nut and give it a tighten but i`m worried about making it worse,or breaking it which would create a problem as the boat is anchored out. Is it a regular event to have to snug them up occasionally or should I leave well enough alone until haulout?
 
I would leave them alone until haul out, if the whole fitting turns in the hull, the leak will get worse.
Smear some 5200 around it for now.
 
fwiw: I have never had the need nor desire to tighten the nut on a thru-hull. As far as I know, it is the sealant that stops weeping; the nut simply holds the fitting in place. If the nut is -loose- then it likely needs to be tightened. but otherwise, I would lead it alone.

If the hull is cored or is wooden, you will likely have other, more concerning, issues as well.

I could be wrong... get other opinions.
 
I'd leave it alone until haulout. Are you sure it leaking or possible just condensation? If your going to remove two to rebed then I'd also remove any others and rebed them also. I'd also consider replacing them with new units. A small investment now may result in a huge reduction in headackes later.

Dave
 
I think I'd want to at least know if the nut is loose and could easily be tightened a bit. Can you stabilize the threaded shaft with a wrench on the seacock or w/ a strap wrench? Don't overtighten.
 
you shoudlnt' have to mess with them.. how much do they leak? enough to trigger the bilge pump? how often?

cored hull or solid glass?

it's indeed the sealant which is making the seal, tightening the nut may help but it's not something it's try in water.

what kind of backing plate was used? could the wood be rotting resulting in the nut to be loose?

if the hull is balsa cored, hopefully the builder did it right and had a pad of solid glass around the sea cock otherwise you could have something nasty brewing in there.
 
What Pascal said.

You said "Thru Hull" so I am assuming you are talking about a transducer rather than a seacock. Is that correct?

My money is on the backing plate. In most of the boats I've messed with the inside backing plate is wood and over the years will rot/deteriorate/shrink and leak. In fact I had the exact same problem and fixed it during my repower.

I also had a leaking garbard drain. This was caused by a deteriorated outer ring. If I had tried to tighten it while the boat was in the water I would have likely broken it and had a hell of a mess on my hands.

Bob
 
It`s just enough to keep it wet,I`ve never seen the bilges come on by themselves but I turn them on manually once every couple weeks and the front one will pump a good stream for 30 seconds. I`m going with my first instinct and the advice here to leave them till haulout. I also agree that the wood backing plate has shrunk/ rotted although it is covered w/glass. I like the idea of replacing them with new and will check the hull. To be honest, I`m not sure but I`ll assume the hull is cored, 1998 Regal 402.
 
If the leaking is a concern, I'd use some 'stay afloat, and smear around the fitting inside.
 
You can never fix a leaky transducer from the inside. It must be removed and replaced with a new fairing block and sealant. If the surounding core material is wet, you must wait it to be completely dry before finishing the job. If in doubt, it would be wise to pay a fiberglass repairman to look at it before you put it back together.
 
a 30 second stream on the bilge pump is quite a bit, it should be more than enough to trigger the float switch. when is the last time you checked if the float swtiches are actaully working?

ideally, they should be checked monthly... physically lift the float and see if the pump starts.

teh backing plate shouldn't have rotted if it was glassed... hopefully if the hole is cored there is a pad of solid glass around the TH
 
Bob, it`s actually one of each, the one in the aft bilge is a transducer for a depthfinder I no longer use and the one in the forward bilge is the seacock for the macerator.
Pascal, the floats work, I think the reason the forward bilge pumps so long is when my boat has low fuel tanks and a full water tank, (Like now) it will actually sit at rest lower at the bow . When I turn on the pump water runs to it from the bow for a while.
 
there is a special tool used for seating thru hull fittings. it is a stepped cone with a notch in it used to lock the fitting from the outside with a wrench so you can tighten the nut from the inside. if you have one and can get a diver to hold it in place for you, the nut can be tightened as a temp solution.

it is very good advice, as others have noted not to mess with this until the boat is on the hard. if something goes wrong you might be going for a haul out alot sooner than you planned.
 
I wouldn't do anything until haul out. Have the area checked closely for moisture and take out the transducer and have the hole glassed in.
 
Just a note that a haul out is not necessary to replace a thru-hull. An experienced diver can do this. I had one changed out because it was leaking and I messed with it, trying to tighten it.
Maybe the suggestions to leave it alone should be considered by you. Wished I had asked.
 
You could make your own wrench if the through hull has tabs inside. Use a flat bar the same size as the hole, bent at one end, will work, or a barr with a square 2 long X 3/16" and wide as the size of the inside of the through hole welded to the bar.
 
My experience with PLASTIC through hulls is that if you tighten them too much they can "jump" a thread, putting you back to square one. Replace them with BRONZE and put a RUBBER gasket under the flange on the OUTSIDE. No more problems... Yes you can do it while the boat is in the water (been there done that).
 
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