Common leak locations on 1985 Mac 25 and rub rail advice

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Seadoc
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Common leak locations on 1985 Mac 25 and rub rail advice

Post by Seadoc » Tue Jan 29, 2019 11:22 pm

My 1985 Mac 25 is being restored and is up on poppet stands. I have an on-going problem with water accumulation/appearance in the following interior areas:
1. On the surface of the V-berth liner where it seems as if it may be running down from the area of the hull-deck joint (brown water streaks on hull liner). Note also that I have seen water dripping off the underside of the V-berth overhead which is the bare, painted underside of the foredeck.
2. At the aft end of the port quarter berth where it pools.
3. On the stbd side along the stringer in the space beneath where the compression post rests on the hull liner.
4. On the port side in the space inboard beneath the access holes in the port setee.
5. In the bilge space in the area where the keel cable passes from the winch to the keel. This seems to be the collecting point since the vessel is slightly "down by the stern" due to the terrain on which she is stored. (I live in the Blue Ridge Mts. of VA.)
I've suctioned it out and sopped it up with rags, but it keeps re-accumulating.

The rub rail insert is partially missing although not in the forward part.
AND while on this subject, has anyone replaced the rub rail insert on their boat?

Thanks for any help you can provide.

Maraquita
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Re: Common leak locations on 1985 Mac 25 and rub rail advice

Post by Maraquita » Wed Jan 30, 2019 8:55 pm

I had a mid 70s Venture 25, which was the same boat, and fixed nearly all of my water ingress problems by re-sealing around the chain plates. It looks like a small area, but it is amazing how much water will pour in there during a driving rain. It is a pain to remove the metal ring and you have to get creative to reinstall it after you pack the hole in the fiberglas with RTV or similar. Make sure that you use something very flexible, because these plates move a lot due to the rigging and hull flexing.

I also found that some of the water in the bilge came in from the keel mount bolt and the keel lock down bolt if I drove her hard enough. Originally these had large rubber washers as seals, and when I owned the boat in the late 80s you could still buy them. You might have to get creative today. If it is still on the original trailer, you can pull the keel mount bolt without the keel moving, but if the trailer is modified or has been replaced, be careful. That chunk of iron is heavy!

The hull joint actually has the deck piece over the top of the hull and the open part of the sealed joint points down, so I doubt that rain water gets in there. You might get some water in if you heal it enough, and of course each bolt could leak a little bit. They are a pain to reseal.

I never replaced the rub strip, but I did remove and reinstall it a couple times. Lube it well with Silicone grease and be ready to have sore hands and thumbs by the time you get it in the channel all the way around.

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Seadoc
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Re: Common leak locations on 1985 Mac 25 and rub rail advice

Post by Seadoc » Wed Jan 30, 2019 11:12 pm

Maraquita,
Appreciate your input.

Did you remove the chain plates or just the small plates around the chain plates that are held on by rivets? BTW replacement cover plates are available from Blue Water Yachts.

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Tomfoolery
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Re: Common leak locations on 1985 Mac 25 and rub rail advice

Post by Tomfoolery » Thu Jan 31, 2019 8:10 am

Maraquita wrote:The hull joint actually has the deck piece over the top of the hull and the open part of the sealed joint points down, so I doubt that rain water gets in there. You might get some water in if you heal it enough, and of course each bolt could leak a little bit. They are a pain to reseal.
It's possible, but I don't know how likely, that someone tried to seal it up at the rub rail and actually caused it to dam up and get up into the joint. That's common on things like brick facade lintels, where the brick is supported by a length of angle iron. Folks caulk the bottom gap, effectively damming the water, making the leak and/or ice damage problem worse. The rule with brick is, water is going to get in to some degree or another, so make sure you leave ways for it to get out. Same applies to boats and other stuff in the weather, to varying degrees.

Just a thought. :wink:

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Tomfoolery
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Re: Common leak locations on 1985 Mac 25 and rub rail advice

Post by Tomfoolery » Thu Jan 31, 2019 8:12 am

Seadoc wrote:Did you remove the chain plates or just the small plates around the chain plates that are held on by rivets? BTW replacement cover plates are available from Blue Water Yachts.
There are a number of threads here about how to do this. Basically just drill out the rivets, clean up the mess, and put the plate back with flexible sealant. I used butyl tape, which remains flexible almost forever. Pop rivet them back on, or use screws. And those connections do flex, but the cover plates don't take any load normally, so it doesn't take much to hold them in place.

Here's one short thread I found in a Google search, using this forum name and my screen name. The search function is having problems, so using Google or another search engine can usually find what you want here.

viewtopic.php?f=8&t=26785&p=335355

Maraquita
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Re: Common leak locations on 1985 Mac 25 and rub rail advice

Post by Maraquita » Thu Jan 31, 2019 8:03 pm

Seadoc, Tomfoolery is right, I never needed to remove the fittings, just the cover plates on the deck

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Re: Common leak locations on 1985 Mac 25 and rub rail advice

Post by Rackman » Mon Feb 04, 2019 9:46 pm

I had to seal the chain plates on my Venture 2-24 the same way. Drilled the rivets, filled the area with butyl tape and used small screws to put it back together. Going on at least three years now with no more leaks.

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