water in bilge, not the CB bolt

[SquamPC]

Hello,

Got myself a beautiful 2001 PC that I've been sailing this summer on Squam Lake in NH. 

I've noticed that I get water in the bilge after several hours on the water, an inch or so. 

The CB bolt/washer/seals were corroded and I replaced these and do not appear to be leaking (thanks to the forum). 

When it is sitting on the trailer after a sail it appears to be leaking water from the centerboard box somewhere along where the screws/metal strip attaches to the hull.  There also appears to be a broken or missing screw. 

Any advice on how to approach this? 

Gregg

[bruce]

The SS CB trunk flange/keel joint doesn't often leak, but yours clearly is. At least you can see the drip, so you're not guessing.

The CB trunk is fastened with self-tapping screws, I'd guess #10. Here's a photo taken from the port side locker looking forward, you can see the pivot bolt washer at the top left. Replace and bed the missing screw, you may get lucky. If you still have a drip, I would carefully inspect the bedding along the full length of the flange, inside and out, for any evidence of localized leaks. If nothing presents, and you still have a drip, I would dam any suspect areas of the joint with modeling clay and fill just those areas with water. If you do locate isolated sections that leak, but the rest is sound, you might be able to dig out and rebed the flange in just those areas. Fluorescent dyes may help locating leaks.

Rebedding the trunk entirely is doable, but at some effort. If you do stop the drip, but continue to have water collecting in the bilge, I would suspect the CB trunk cover/cockpit sole joint (again bedded and screwed), or the drain pipes from the cockpit where they pass through the transom. Cracks in the PVC drains have been found, and Com-Pac glasses the pipes in place. PVC doesn't glass well.

[SquamPC]

Thank you!  That is really helpful information.  I'll get on it. 

[Dave-in-RI]

Garboard plug another possibility with many places in New England requiring you to open and drain it on the spot-- check the rear inspection port to see what's dusty and what's not. I had a leaky CB housing on a PC and used the cockpit drain plugs on the scupper intakes to then fill the dam below and make "dam" sure it was isolated. Alas, it was. Good luck!

[bruce]

Yeah, the garboard plug could leak, but rarely does. It is a proper thru-hull fitting with a flange to bed on the outboard surface, i.e. at the source. Com-Pac glasses the cockpit drain on the inboard transom surface, and uses caulk to hopefully seal the pipe to the hull and plywood core on the exterior.

Renae experienced problems on his SC, which Com-Pac does the same way. He was able to dig out and replace the caulking. Thru-hull fittings, at least at the transom, and flexible tubing to a cockpit fitting would be better practice.
https://cpyoa.com/forum/index.php?topic=11486.0

Hopefully Gregg will be able to solve his problem at the CB trunk flange. No core here, I assume, so a little leak wouldn't cause additional problems down the road.

[SquamPC]

Update: I got in there and inspected the caulking along the CB box and screws thoroughly. After attempting to remove a section of caulk that appeared deteriorated the remaining caulk started to lift.  Only about a 2 inch section was still intact, the rest lifted off effortlessly. I spent several hours removing any residual caulk along the CB box and the screws, then I went over the area with a small wire brush and cleaned thoroughly with acetone.  The Com-Pac service department was helpful and recommended several marine caulks, I used 3M 4200 (because it was available) to reseal the CB box and screws and I replaced the missing screw (#12, a size up because the original size was not biting).  Took her out this past weekend and she was bone dry.  Thanks for the assistance!   

[bruce]

Excellent, glad you could stop the leak! Just to be clear, when you say CB box I assume you mean the flanged stainless steel trunk bonded to the hull, as you originally described. The CB itself weighs almost 75 lbs., and with the trunk it must be about 300 lbs. That, and having to work under the boat requiring the boat to be off the trailer, or at least lifted high enough so that you had clearance to drop the trunk a few inches, must have made the work more difficult. Can you share details how you approached the job.

Rebonding the CB trunk cover in the cockpit to the sole would be a pain, but much easier than the CB trunk to the hull. Your boat may be early enough so you have the original mahogany cover. Most of us have the latter fiberglass version.

[Dave-in-RI]

Sounds like he was working inside the lazarettes where the screw points enter the bilge, not the exterior where the screw heads are, or the flange. That's what Gerry suggested to me with my PC— just caulk over the screws and joints from the inside and call it a day.

[bruce]

Thanks, Dave. I do now recall having this discussion with you and not being convinced this would yield lasting results. But hey, if it's working then that's all that matters!

[SquamPC]

Sounds like he was working inside the lazarettes where the screw points enter the bilge, not the exterior where the screw heads are, or the flange. That's what Gerry suggested to me with my PC— just caulk over the screws and joints from the inside and call it a day.

Yes, I was in the bilge (not the greatest place to work for several hours).  The 20 year old caulk was no longer adhering to the joint or screw points. I believe the majority of the leak was coming from the loose screw that I replaced and caulked into place.       

[bruce]

I'm sure it was tough working in the bilge, I'm sore just thinking about it.

Com-Pac does love their 2" self-tappers. I understand not wanting to stock different lengths, but is there ever a time they need 2"?