Finding and fixing leaks

Phil Herring

Alien
Mar 25, 1997
4,918
- - Bainbridge Island
If youve owned a boat longer than 20 minutes youve dealt with a leak. Or two. Or more.

How have you tracked them down and once found, what did you do to make the repairs?

 
May 1, 2011
4,189
Pearson 37 Lusby MD
Had a leak in my dry goods locker. Thought it was coming from the stanchion just above or the water fill port. I couldn't find the leak initially and neither could the boatyard. Turned out that water was leaking through the mast boot and following the path of least resistance behind the head liner to the dry goods locker. I replaced the mast boot tape and all is well.
 
Oct 5, 2015
80
Hunter 33 33 Halifax
On my 2007 Hunter 33 I have an annoying leak I can't seem to isolate. When I drain my ice cooler I get water around my thru-hulls.
Does not seem to happen when I drain the sink.

Thoughts,
 
Apr 19, 2015
18
Hunter 27 Midway Marina Catawba Island Lake Erie
I believe most of my leaks on my 1980 Hunter 27 are coming in from the toe rail and stanchions. Outside of removing the entire rail and all the stanchions, is there an easier method to fixing these? I have yards of butyl at the ready. Going to do something, but looking for advice from others who have found the best approach.

Also, what is the easiest way to loosen/tighten all the bolts for the toe rail and stanchions from inside the cabin as the bolts are so much deep that getting to the nuts is a problem. Obviously cannot get a drill into most of the spaces to do it quickly.

Thanks!
 
Oct 22, 2014
20,993
CAL 35 Cruiser #21 moored EVERETT WA
When I drain my ice cooler I get water around my thru-hulls.
Just guessing here. Your ice cooler is draining towards the bilge. Hunter boats use a pan system to install the interior. The draining ice cooler water is being directed to the through hulls via weep holes in the tabs holding the pan to the hull.
 
Jun 8, 2004
10,024
-na -NA Anywhere USA
An old way was to close up the boat, sealing hatches and so forth with tape and putting a one piece of plastic over the companionway taped down too. Insert a leaf blowers thru plastic or something likewise and tape around it. Have a person standing by with a bucket of soapy water with brush to brush everything once leaf blower is on which in essence you are pressuring the cabin and where you see air bubbling out could be a potential leak
 
Apr 19, 2015
18
Hunter 27 Midway Marina Catawba Island Lake Erie
That is sheer genius!

An old way was to close up the boat, sealing hatches and so forth with tape and putting a one piece of plastic over the companionway taped down too. Insert a leaf blowers thru plastic or something likewise and tape around it. Have a person standing by with a bucket of soapy water with brush to brush everything once leaf blower is on which in essence you are pressuring the cabin and where you see air bubbling out could be a potential leak
 

mark2

.
Dec 10, 2012
54
Hunter 18 Raleigh
After 2 years we still cannot find the source of a between-the-hulls leak in our 170. We have measured, and it leaks about 2 gallons per hour in moderate winds (less in lighter winds). Our latest attempt was to fill the hull cavity with water while the boat was on the trailer and see where it came out... but of course there was not a drop or drip on the entire exterior with the hull filled for hours. UGH!

I guess we can try to pressurize it and spread soapy water around but I am not optimistic...
 
Oct 22, 2014
20,993
CAL 35 Cruiser #21 moored EVERETT WA
@mark2 if I understand this you filled the hull with water and no drips. That’s a great discovery. :yeah:
So now it appears the leak is coming in above the level of water you placed in the hull. The leaf blower inflate sounds like a good idea to find the leak or leaks. 2 gallons an hour is a lot of water.
 
Sep 26, 2008
546
Hunter 340 0 Wickford, RI
This started from the the day we bought our boat new in 2000. Our 340, had a leak in the aft cabin, port side, that soaked the walls and found its way to under the bedding and puddled up along the back cabin wall. I could push on the thin foam wall covering and squeeze the water out the bottom.
Being under warranty, the process began. I have to say Hunter really tried. They replaced ALL the opening ports and fixed windows. Rebedded the Arch and even replaced and rebedded each snap in the cockpit the hold the cushions.
Nothing worked, I spent days in the rain trying to chase water.

On the 340 there is an access panel about 3 inches wide, with about 30 screws above the fixed window. I removed the panel to look in to see if I could see any signs of water. My hands still have the scars from the sharp fiberglass edges inside there. Be careful!

That's when I saw the cause.
When they built our boat, during the process of glueing the foam wall covering to the hull, they draped the foam over the edge of the hull. Then in the process of lowering the deck to the hull they never cut the foam away from the edge and sealed th deck to the hull.
The water from the Rub Rail would find its way to that area and the foam sucked the water up like a sponge and saturated the foam all the way down.

I took an Exacto Knife and cut the foam along the inside edge, about 8 inches long, pulled it away from the area and never had water since. I did caulk the area under the Rub Rail just to be certain and all is still good.

When they were building the boat, we asked Hunter for pictures of the process and they sent about 10 or so pictures in varying stages. (There are more on my media page). And sure enough if you look close you can see the foam over the edge. Look right behind the guy standing in what is now the locker in the aft cabin and you can see the foam.
When I contacted Hunter and explained what I found they were shocked as I was. Checked my pictures and agreed. I guess I have the only pictures of it.
We can't be the only ones who had this problem in various edges along the boat, given their technique at the time. So it's a place to start looking.
 

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capta

.
Jun 4, 2009
4,766
Pearson 530 Admiralty Bay, Bequia SVG
Food coloring can be helpful for tracing random leaks. Leaks through the deck or cabin top can show up below a goodly distance from the entry point.
 
Aug 13, 2012
533
Catalina 270 Ottawa
Food coloring can be helpful for tracing random leaks. Leaks through the deck or cabin top can show up below a goodly distance from the entry point.
or water-soluble markers (where it leaks, the line you made on the hull would be dissolved)
 

DArcy

.
Feb 11, 2017
1,690
Islander Freeport 36 Ottawa
I believe most of my leaks on my 1980 Hunter 27 are coming in from the toe rail and stanchions. Outside of removing the entire rail and all the stanchions, is there an easier method to fixing these? I have yards of butyl at the ready. Going to do something, but looking for advice from others who have found the best approach.

Also, what is the easiest way to loosen/tighten all the bolts for the toe rail and stanchions from inside the cabin as the bolts are so much deep that getting to the nuts is a problem. Obviously cannot get a drill into most of the spaces to do it quickly.

Thanks!
I have toe rail leaks on my C&C 27. I have fixed the starboard leaks, haven't gotten to the port side yet. With the boat in the water (better hull support), I loosened the screws in the toe rail, about 15 at a time, and caulked along the inner edge of the rail as well as filling the screw holes. I then tightened the screws and cleaned up the squeeze out under neath. I used Life-Caulk and it stopped the leaks. This is a two person job to hold the screws and turn the nuts. I have fairly good access through the cabinets on my boat.
 

nat55

.
Feb 11, 2017
210
Gulfstar 1979 Gulfstar 37 BELFAST
Our worst leak was caused by a nearly catastrophic issue that was created even before we owned our previous boat, an Islander 32, way back in 2000 or so. The previous owner had his yard put new batteries aboard in the spring, a pair of group 31 deep cycles. What was done wrong and I'm not sure how it could have happened but the installer took a cable off the + side and bolted it to the thru bolt that attached the skeg! We had committed to buying the boat and the surveyor was aboard for the trip to the boatyard before hauling it to be sent to Maine.

When they hauled it up in the slings the strut was almost completely gone, the surveyor was shocked as well as the boatyard as this was the same place that had commissioned the boat. They fixed the damage of course, I should point out that the boat was on a dock and plugged into shore power, essentially he had been pumping some serious voltage into the water at his dock, the surveyor said that if the boat had sat on the dock another couple of days it would have sunk right there!

The saga continues as when we got the boat everything seemed good, strut was repaired and the battery wiring was done correctly. Over the remainder of the season, we took delivery in mid August, we had no issues.
The next season I noticed some pretty serious bilge pump activity, I checked the packing box and while it was dripping I didn't think it was unusual. Over the course of that season it got worse, and worse. After a more than cursory inspection I noticed that the stern tube was leaking badly, right where it went through the hull. That became my priority project that winter and what fun that was! after I got the stuffing box and transmission coupling apart the tube broke off, kind of like a loose tooth, remember those? Wiggle, wiggle plink.....so we were lucky we didn't loose it.

No pictures but it was scary.
 
Apr 16, 2017
841
Federation NCC-1701 Riverside
After 2 years we still cannot find the source of a between-the-hulls leak in our 170. We have measured, and it leaks about 2 gallons per hour in moderate winds (less in lighter winds). Our latest attempt was to fill the hull cavity with water while the boat was on the trailer and see where it came out... but of course there was not a drop or drip on the entire exterior with the hull filled for hours. UGH!

I guess we can try to pressurize it and spread soapy water around but I am not optimistic...
@mark2 crawl under the trailer and shine a flashlight into the centerboard housing. Better yet...unscrew the centerboard and pull the centerboard up into the cockpit.

Now shine a flashlight into the centerboard housing. There are a couple items to look at. 1) the centerboard pin is held in with 4 lag bolts. Not likely since you didnt see leaks here.
2) mainheet purchase has 4 bolts through cockpit floor to aluminum plate in housing. Not a great leaker since that should be above waterline.
3) there are a bunch of hull seams and flanges in here, both above and below. Look for cracks. If you pressurize the hull spray in this area.
 
Oct 9, 2013
21
Hunter 30 Lusby, MD
I believe most of my leaks on my 1980 Hunter 27 are coming in from the toe rail and stanchions. Outside of removing the entire rail and all the stanchions, is there an easier method to fixing these? I have yards of butyl at the ready. Going to do something, but looking for advice from others who have found the best approach.

Also, what is the easiest way to loosen/tighten all the bolts for the toe rail and stanchions from inside the cabin as the bolts are so much deep that getting to the nuts is a problem. Obviously cannot get a drill into most of the spaces to do it quickly.

Thanks!
Check/re-bed your ports. I have an 82 Hunter 30 and suspected similar toe rail leaks because the water drips off the toe rail bolts but it was actually coming from the ports and not the stanchions or toe rail.