Thru-Hull Repair?

[Ariose]

This is one of those "I-think-I-know-what-we-need-to-do-but-hope-to-hear-we-don't" questions.

In preparing our Alberg 30 for some upcoming coastal cruising, we noticed corrosion on one of the stopcocks. While removing the valve to replace it, one of us (who shall remain nameless), noticed a "give" feeling and thought he felt some movement of the thru-hull fitting. I went below to observe from outside (the boat is on it's trailer... thank goodness), and sure enough, a gentle twist from inside does cause an every so slight rotation of the fitting on the hull. There may have been expletives uttered from inside & outside the boat.

We don't know what bedding compound was used, but assume a polyurethane sealer as most work on the boat by past owners seems to have followed standard practise. We're quite new to sailing and boat maintenance, and aren't familiar with the properties of polyurethane, but know enough to know that we don't want to be dealing with a leaky thru-hull when underway.

So, would this kind of slight movement have compromised the seal? Do we now need to remove, clean then rebed the fitting?
thanks, in advance, for any/all advice.

Shirley
Ariose Notes | We're a "north-of-49" novice cruising couple sharing our musings about life & learning on our classic Alberg 30 sailboat. Welcome aboard!

[Stevens 47]

Yes and Yes. Do yourself a favor and purchase Nigel Calders Boatowners Mechanical and Electrical Manual, it covers pretty much all you will need to know to maintain your boat and then some, including how to install seacocks and thru holes.

[fallingeggs]

I would rebed. A leak and a seacock equals a sunk boat.

It really shouldn't be a large project as it sounds like the seacock wants to come out. Sounds like there is a mushroom fitting? Also sounds like there is no flange on the seacock and no backing plate. Unscrew the seacock from the mushroom and tap the mushroom out.

If no apparent water damage in the hole, clean (seacock, mushroom and the hole) and rebed! I used 3M 4200 as many would recommend. 5200 is too strong for something that may need to come off again in a few years time.

On that last part, if there is no backing plate and the seacock doesn't have a flange, it may be time to pony up the cash for a new seacock with a flange, a new mushroom, and install a backing plate. How old is the seacock anyway? They don't last forever!


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[barnakiel]

Yes. It has been compromised. Ease, replace the bedding, tighten, dry.

Properly bedded fitting is firm under the bedding only. ZERO movement.

b.

[SV DestinyAscen]

Replace the thru-hull - I'd recommend marleon and avoid future corrosion.

[UNCIVILIZED]

Do what the guys said above. Including getting Nigel Calder's book, plus it's "siblings" written by the author.

The through hull in question which moved could have been bedded with Dolfinite, or something like it. As it's a bedding compound which never gets hard, & doesn't have much as far as adhesive properties. It's not something I would use on fittings below the waterline, but it's another possible explanation for your loose fitting.

To some degree Dolfinite is/was like an ancient progenitor of Butyl Tape. And was commonly used to bed fittings on deck due to it's perpetual flexibility. But obviously there are much better compounds available. However it did have some other unique perks in it's original formulation as well.

[Ariose]

Thanks everyone, for confirming what I should have known, and for the helpful suggestions on resources, materials, etc.
PS - Nigel did provide excellent reading over breakfast this morning in preparation for our Saturday task: removing the through-hull.