Can someone identify where this mysterious water is coming from? (Photo)

[dad_n_Seattle]

Yeah, I thoroughly cleaned and inspected the hole where the saltwater inlet valve and fitting was - it is definitely solid GRP. I suppose it is possible that the semi-transparent area is a patch, but it would be a shallow patch that doesn't go through. One other observation is that there was no paint under that scoop. Just sealant and what you see. No barrier coat, no old antifouling.

[Cheechako]

Originally Posted by dad_n_Seattle

Yeah, I thoroughly cleaned and inspected the hole where the saltwater inlet valve and fitting was - it is definitely solid GRP. I suppose it is possible that the semi-transparent area is a patch, but it would be a shallow patch that doesn't go through. One other observation is that there was no paint under that scoop. Just sealant and what you see. No barrier coat, no old antifouling.

I guess it was determined your boat isn't cored earlier.. ? I'm really surprised it's that thick. The 44 ft boat in my avatar was probably about 1.25" thick in the same area.
If your boat was cored, it may have a donut ring of solid glass around the through hull hole to seal it and appear to be solid. Good builders would do that right?

[Cadence]

Originally Posted by chasfgr

I know of no reputable builders who built cruising hulls with balso-cored bottoms, though many out and out racers did this.


I think there may have been some water ingress between layers of GRP, not usually a disaster, unless the gel-coat starts bubbling.
Much has to do with whether the boat is in salt or fresh water - but having made sure the bilge is empty it would be worth having someone, with a moisture meter (and knows how to use it) to check for levels of water retention in the layup.
Check if fresh or salt water, if the former it's probably a leak from bilge through internal fixings. If the latter you may have an expensive problem.

If water ingress between layers of GRP has occurred there is a major problem. The layup was piss poor.

[Singularity]

Originally Posted by Dougtiff

I'm not an export with your problem, but have seen this kind of issue dealt with by drilling about a 1/4" hole, inserting a fitting that a VACUME pump is attached to, after tapping out the area, and drilling some 1/8" holes in the area with issues, Acetone is injected into the 1/8" holes while under vacume, removing moisture, epoxy is injected into the 1/" holes after vacuming is completed, the vacuming can take a day or more depending.

I agree that a vaccuum pump (even <$100 Harbor Freight model) is quite useful, but no need for acetone/solvents that I'm familiar with. The water will go from liquid to gas phase simply with the lower pressure; the key difficulty is getting a good seal on the periphery of the substrate. Vaccuum bagging supply places sells double-sided tapes, manifolds, etc, for cheap to get the job done.

Not asked/reported above I don't think.......but what does a simple tap test reveal around the suspect area???

[jimbunyard]

Believe what we're seeing here is the combination of the internal liner and the hull, which combined total the uncharacteristic thickness.

Since there is no sealant evident around the screw hole, I would take that as the prime suspect for at least some of the water entry, but if the liner isn't well-bonded at the spot where the through-hull penetrates, especially if the sealant used has hardened since installation, water could be entering there as well, and there may also be other areas.

Do you have a separate strainer? If so, I'd be tempted to get rid of the external strainer and replace it with a standard mushroom through-hull, (just think of the extra speed you'll get, haha), then fill the screw hole and be done with it.

The 100% fix would be to remove the liner around the through-hull aperture so that the nut clamps against the hull only, using a good, non-hardening sealant or adhesive sealant. If you want to use the external strainer, get rid of the screw, drill the hole all the way through and use a bolt, nut and fender washer, well slathered with sealant (and injected into the hole before insertion of the bolt) to secure the end.

The gray circle in the intake side of the strainer outline just looks like exposure of the gelcoat to the elements, but pictures are notoriously deceptive.

[mitiempo]

Originally Posted by Cheechako

Plenty were actually, C&C for one, later Sabre's also. Although we could debate if those are "cruising" boats.

All Dashew's Sundeer 56,60,and 64 were balsa cored by TPI.

[jhulmer]

Is that a blister in the gel behind the screw? Tap that area and around the through hull. You may only have a large blister full of water. As Gord pointed out the water will stink.

[Manateeman]

Hi. I agree with Jimbunyard that it looks like liner and hull. Cut into the liner but not the hull and remove enough so you can see what’s going on. I’d get rid of that external strainer. Reinforce the hull, glass and epoxy. Then put in a Groco seacock and a regular thru hull, correctly. I’d be looking for ways the water got between the liner and the hull. You can drill some small test holes to see then fill them with epoxy. You need more information on how your boat was built before say adding or removing seacocks and if you do have water between the liner and the hull, more info before I would suggest anything.
There is a web page something like marine how to ? where they do seacocks correctly. If you cut out the liner, you can put in an inspection plate or plexus it back in . Not rocket science. The more you know how the boat was built, the easier it is to fix correctly. That’s what is needed now. Till then...
Happy trails to you.
Captain Mark and his Plexus Packing manatees. Stick em up Partner.

[DeValency]

Originally Posted by coopec43

My immediate thought was that it was coming from the core.

How did it get there? Is it salty water or more like rainwater: that would be a start.

I wouldn't be in a hurry to put the yacht back in the water until you solved the problem.

I would begin by removing the through-hull as water may got into the core from poor external (or internal if you had water in the bilge in the past) sealing.

At any case, you want to do this in order to start examining the core all around. It may just be the beginning of an unpleasant surprise - hope not! At any case a proper repair would require the removal of the through-hull as a first step.

[jimbunyard]

Originally Posted by Cheechako

....Good builders would do that right?

Good builders would do it like that. The best builders (of course, in my opinion) would do it like this.

[DeValency]

Originally Posted by jimbunyard

Good builders would do it like that. The best builders (of course, in my opinion) would do it like this.

Sorry but I can't agree here: Such a structure will create weak points and stress areas not backed by the geometry of a sandwich hull.

The good builders I know, remove the core at ~1-2" around the hole and fill it with glassed epoxy. This also provide the appropriate horizontal support to the through-hull.

[Singularity]

Originally Posted by DeValency

Sorry but I can't agree here: Such a structure will create weak points and stress areas not backed by the geometry of a sandwich hull.

The good builders I know, remove the core at ~1-2" around the hole and fill it with glassed epoxy. This also provide the appropriate horizontal support to the through-hull.

FWIW Jim's "skin-to-skin" is used in critical areas of a few composite aircraft I'm familiar with, including in fuel tank fittings where the tank has foam core walls where it's critical that fuel never gets into the core. By itself making a hole in the skin-to-skin attachment provides no weak point or stress point about some frankly small hole. But the seacock...

I'd suggest that a better boat builder would use Jim's skin-to-skin approach, then build up atop (in this example, the inside skin) reinforcement to support seacocks or other attachments that might torque on the hole. But this is more work than simply reaming out core about the hole and filling with slurry, which is good enough.

All in, an academic discussion for this case. I would like to to know what a tap test finds in the OP's situation.

[mitiempo]

The op's boat doesn't have a cored hull.

[jimbunyard]

Originally Posted by DeValency

Sorry but I can't agree here: Such a structure will create weak points and stress areas not backed by the geometry of a sandwich hull.

The good builders I know, remove the core at ~1-2" around the hole and fill it with glassed epoxy. This also provide the appropriate horizontal support to the through-hull.

Trying to neither change your mind nor convert anyone else, but no it won't. Doing it the way illustrated actually spreads the load and reduces stress points because of the tapers used in conjunction with the inherent slight flexibility of fiberglass hulls (even cored ones). Furthermore, (and more importantly, since for a hull built to the proper scantlings, either type construction will adequately support a seacock, but core water intrustion will definitely compromise that function) depending on the technique and method used to 'remove and fill' the 'about 1-2" around the hole' at least doubles and possibly quadruples the chances for core water intrusion at some point in the future.

But of course this is just my opinion --- based on many dozens, or perhaps low hundreds, of new and repaired through-hull installations...and lots of cored hull design and refit.

[boatpoker]

As several have mentioned, there is no core in this hull. It is a full pan liner bonded to the hull with Plexus adhesive.The hole shows the outer glass, then the Plexus and then the liner.

My money is on water accumulating between liner and hull.

This may (or may not) help ....
Moisture Meter Mythology and Flir thermal imager

Pay attention to hull thickness when using a moisture meter as despite mfg's claims I've never seen one measure more than 3/8" thick FRP. Often the centerline and around the keel will be much thicker than this. The further you get from the keel and centerline, the thinner the hull.