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Where is my leak coming from?

Posted: Mon May 06, 2019 12:00 pm
by bobbob
Hey all, for the past two seasons I have tarped my :macx: from the mast aftwards over winter (including the entire cockpit and motor well). And for the past two seasons I have experienced water in the bilge underneath the aft berth, as well as a small pool of water right at the back of the aft berth. Last year I tried to determine the source of the leak with a hose and was completely unable to.

This year I noticed some dripping from the white fiberglass moulding right at the back of the aft cabin, right below where the motor well is. I cant for the life of me see how water would run to this "drip edge" in the first place, unless its running along the length of the boat between the top deck and the inside trim moulding. I put a wallpaper paste tray underneath this drip edge and it has caught some water during the rains the last couple of weeks, but I'm pretty sure I am still seeing more water in the bilge.

The other thing I'm noticing is it looks like there is some evidence of weeping from the bolt holes that hold on the rudders. It seems impossible for water to get in here though from the outside so I'm wondering if this is just humidity.

Also note that I see no evidence of water in any other part of the cabin (either pooling or even water trail "stains"). So if the leaking water is running inside the cabin somewhere before entering the bilge the exact route escapes me .

Any ideas on how to debug this?

Thanks!

Re: Where is my leak coming from?

Posted: Mon May 06, 2019 12:12 pm
by DaveC426913
Have you checked the line and connection from the engine well scupper?

Leakage in the connector is a very common problem on Macs.

Re: Where is my leak coming from?

Posted: Mon May 06, 2019 12:17 pm
by bobbob
Last fall I ran a garden hose into the engine well for about 15-20 minutes and saw no evidence from the inside that there was any leaking. Also, since the tarp should in theory have prevented any water from getting into the cockpit and draining to the motor well, my assumption is that this is not the issue. (Also, the dripping from the inside drip edge underneath the motor well doesn't seem possible to come from the motor well drain?).

I can have another look at all of this this weekend though.

Re: Where is my leak coming from?

Posted: Sun May 12, 2019 12:23 am
by Carioca
All deck hardware bolts are suspect. I just rebeded all with butyl tape.

Re: Where is my leak coming from?

Posted: Sun May 12, 2019 8:36 pm
by NiceAft
Where it is dripping is not necessarily the source. As we all know, water will flow to the area of least resistance. Have you tried feeling, or blotting to find a trail?

You say the boat is completely covered with a tarp. Are there any exposed areas? Are there any holes in the tarp?

If you saw puddling on the aft bunk itself, then it’s logical for the source to be higher.

There has to be a reason.


Ray

Re: Where is my leak coming from?

Posted: Mon May 13, 2019 11:45 am
by beechkingd
Carioca wrote:
Sun May 12, 2019 12:23 am
All deck hardware bolts are suspect. I just rebeded all with butyl tape.
I have similar leaks to the OP. I fixed a number of leaks that were ending up in the aft bunk area, but randomly end up with water down there still. It's strange that it will have a puddle some times after a storm but not always... I ended up making a sheetmetal gutter about 3" long that deflects the water to the stern so it will go to the bilge to keep it out of the cabin floor. It's only a small leak so at least the cushions stay dry now.

How do you access the deck hardware? I need to pull them next year and seal/tape them. I suspect I'll have to drill quite a few holes to get access to the nuts for most of the things on the sides of the cockpit. Are there any pictures of access holes people have added to get to them?

Re: Where is my leak coming from?

Posted: Mon May 13, 2019 4:46 pm
by Jimmyt
I've heard of folks dusting the bilge with talcum powder to create visible leak trails. Might not help if the leak originates at deck above liner, but might eliminate some areas.

Re: Where is my leak coming from?

Posted: Mon May 13, 2019 7:18 pm
by ramirezpm
To find leaks inside, the Great Don Casey recommends using water soluble marker on the bulkhead. You can draw a line up high and leave it to see any runs.

Re: Where is my leak coming from?

Posted: Tue May 14, 2019 2:16 pm
by bobbob
I think I figured it out - the metal plate that the boarding ladder uses to attach to the cockpit deck has some caulking that was loose. I think water is seeping under the ridge of that metal plate.

I cant fully see the path from there to the drip edge underneath but I do see evidence of water weeping down the inside of the transom and into the bilge that way, and it seems localized to the port side which is where the ladder is mounted.

Re: Where is my leak coming from?

Posted: Tue May 14, 2019 3:21 pm
by Carioca
Deck hardware can be removed by pulling all access caps on liner inside, I set up cordless impact and had a spotter on top .
Butyl tape is easiest, just roll little donuts for contact points on screws.