Macgregor 26s leak

A forum for discussing topics relating to older MacGregor/Venture sailboats.

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First Officer
Posts: 269
Joined: Thu May 08, 2014 7:31 am
Sailboat: MacGregor 26S
Location: Great Plains

Re: Macgregor 26s leak

Post by Interim » Tue Oct 19, 2021 8:52 am

sorry; I put this in the wrong thread. My leak discussion is "that sinking feeling."


Posts: 820
Joined: Mon Sep 28, 2020 11:16 am
Sailboat: MacGregor 26X
Location: NH SC

Re: Macgregor 26s leak

Post by OverEasy » Tue Oct 19, 2021 12:08 pm

Hi SvScott!

Hope you have had a great summer on the water.

I’ve used a variety of purported UV resistant silicone sealants and adhesives over the years (professional and personally) and have found myself disappointed 😔 each time when applying it, cleaning it up from where it wasn’t supposed to be and very disappointed when inspecting aged installations. Actual glass does tend to initially clean up better than acrylics or gelcoat.

But getting back to the original surfaces after a silicone application has always been a real problem for me. Any suggestions for getting it off surfaces would be appreciated.

The other aspect I’ve incurred is the silicone not being very compliant after it has cured out. This has been problematic with clamped screw type applications such as the windows on a Mac. Tightening the screw/nut clamping when a leak inevitably occurs only makes the situation worse in my experience.

The butyl sealant on the other hand when properly applied generally allows for gentle RE compression and flows compliant to the surfaces.

The butyl material wasn’t designed to be in an exposed condition, it was designed to be in a captured condition between surfaces. If treated as a general filling material with large exposed surfaces then yes, eventually it will lose its oils and dry out. But when used to seal clamped surfaces (not over compressed) and the excess properly trimmed I have not found any issues even on applications in fully exposed (wind/rain//parched/sun/heat/cold) environmental locations.

What I’ve really come to appreciate about the butyl putty,aside from the long term durability) is the forgiving nature it has when having to remove & reinstall panels. I’ve had situations where I’ve reused the same butyl putty multiple times with excellent results after kneading it back into a putty.

I’ve never been able to do that with silicone products. Even when the material has been able to separate from a panel. It has never satisfactorily resealed without another application of fresh silicone material.

Again, this has just been my own experience.

I have a house/yard project coming up where I am going to be needing to seal an exterior acrylic panel to an aluminum frame and will give the compound you suggested a try to see how it performs over time.

Never too old to try a new trick. 😊

Best Regards,
Over Easy 😎😎🐩🐈

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Chief Steward
Posts: 63
Joined: Thu Nov 12, 2020 7:50 am
Sailboat: MacGregor 26S
Location: Grapevine, TX

Re: Macgregor 26s leak

Post by Stickinthemud57 » Tue Oct 19, 2021 7:14 pm

It seems to me it will be necessary to determine the conditions under which the boat is taking on water. Mine does when it rains, so it's plain that there is a leak at a window or cracks in the deck. I also have a Hunter 170 that stays dry unless I have it out on a windy day, which indicates a leak in the centerboard trunk, since everything else is sealed up.

Another source for water entry in the 26S is the sink drain. My sink lets water in when the boat heels, so if the drain line from the sink to the port on the starboard side is leaking, that could be a source.

3 to 4 gallons is a lot. If this is coming in while the boat is at rest, then of course the leak is below the waterline. If it only comes in after sailing, then suspect something above the waterline.

I can't see why the inside of the centerboard line tube being smooth or not would have any impact, but it is a strange universe we live in.

First Officer
Posts: 251
Joined: Fri Aug 12, 2016 8:35 pm
Sailboat: MacGregor 26D
Location: Erie PA

Re: Macgregor 26s leak

Post by svscott » Thu Oct 21, 2021 3:05 am

Overeasy, it's been a great year on the water but it's sadly coming to an end soon.... marina days I've got another week and a half until haul out deadline.

When using caulking, the key to easy cleanup is to not make a mess in the first place! I tape off everything surrounding the caulk bead with at least 2" of tape and the tape gives a nice clean line once the caulk is tooled and removed. When tooling the sealant around my boat windows, I have found a plastic spoon works great for shaping the bead, followed by a bit of nimble finger work to smooth any areas where you pull the spin away to clean off excess, prior to peeling the tape. Since my youth, I've literally laid miles of caulk... and I'm a creature of habit and convenience so I use what I know and have access to.
As for clean up, you're right, butyl tape is superior.... a quick wipe with some solvent (kerosene works great) takes care of it, but the Dowsil 795 takes a bit more effort. When redoing my D and X windows, after reviving the plastic, I razor blade the heavy areas, taking care not to gouge gelcoat then use a scotch brite pad with denatured alcohol, then carefully sand the area with 120 grit and wiping clean with more alcohol and scotch brite (taking care not to scratch up beyond the caulking). In my experience though, newly applied 795 seems to adhere to cured 795 acceptably so I didn't bring it down to 100% clean gelcoat.
You're also right about once the caulk has released that it won't reseal without re-application but in this rare situation, I cut out the bad area and reseal with new sealant.
1987 26D - Three Hour Tour; 1998 26X - to be named

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