Lewmar Portlight leak mystery

Roc · May 19, 2008, 11:46:07 AM

Hi All,
Have a leak that I can't seem to trace down. It's the Lewmar portlight, starboard side, forward most in salon (middle one if looking at the deck from outside). I found the leak because the forward most screw that holds the teak trim that runs along the interior showed water stains on the wood. When I took the screw out, water came dripping out. I put a sprig of paper toweling inside the hole, the paper came out wet. Also, when the plastic trim is removed, the core seems like it has gotten wet because of it's slight amber color (other portlights show the core to still have mfg dust and are lighter in color). I've sprayed the hatch with water while looking at the inside of the hatch with no success. The gaskets don't leak. The little grey rubber gasket that is in the slit where the extrusion frame comes together at the bottom does not leak (called Lewmar and they said to look at that). I can't see any evidence of water coming in when I do my splash test.

I think if the bedding was the problem, I would see water seeping through.

Thanks!!

rirvine · May 19, 2008, 12:05:09 PM

I would suspect that water is getting inside the frame through the "grey" plastic pieces used to join the two halves of the outer trim together. Once it get inside that only way for the water to get out is through one of the bolt holes use to clamp the inner frame to the outer frame - or one of those not used.

Just my 2 cents, Ray

sail4dale · May 19, 2008, 02:21:31 PM

Join the crowd. My leak is the middle on port. A few years ago it leaked and it was the mast base caulking that allowed the water to seep thru to the port where it dripped on my berth.

I caulked around the mast and the leak was gone..... but only for a couple of years.

However, now I leave the hose running on the mast no leak. Not even when I leave it running on the port itself or the port ahead of it. or even the deck fitting in the general neighborhood.

Just when I think it is no longer a problem, I wash the boat and it's back.

This has gone on for over a year now and many hours of hose running have gone into the search with out any tangable results.

Ted Pounds · May 20, 2008, 07:11:05 PM

If they're like the portlights on the MK I then check the O-rings on the dogs that hold them closed. For details there are some early posts on the subject.

dgill · May 21, 2008, 03:39:16 AM

My boat had the same problem with the leaky portlights. Indeed they were the "O" rings on the handles that over 20 years had dry rotted. Contact McMaster Carr (online) and order the rings from them. For a modest price you'll get enough "O" rings that you can share them with other boat owners as I have done. This is a simple fix that solves an aggrevating problem. I believe that Ron Hill will know exactly which "O" ring to order - I just don't have the info with me.

D.Gill
#389

Roc · May 21, 2008, 06:12:35 AM

Thanks for the o-ring advice, but the portlights on the mkII don't have these. There is nothing that passes through the glass.

Wayne · May 21, 2008, 06:51:04 AM

We do have the O rings--they are on the frame part, not the 'window' part, and they are the size of the port. I had a leak occur also. I was told to clean the ring; that dust and dirt buildup could cause a disconnect between the ring and the surface that it seals to. Also it was suggested that a little lubrication in case the rubber was getting a little stiff. Did both and my leak went away. Also, built into the latch is a shim that is designed to be removed as the ring ages. Removal of this shim allows the port to latch more tightly. I don't remember if there is one or two screws that hold the latching mechanism in place, but the shim is pierced by this/these screw(s). In my case a good cleaning and oiling did the job.

Joe Kern · May 21, 2008, 08:54:56 AM

What did you lubricate the rubber with?

tonywright · May 21, 2008, 09:24:53 AM

I have used vinyl cleaner, and silicone spray once it is clean. But to stop the leak, just a damp cloth wiped over the seal and the rim of the "glass" works just fine.

Tony

Roc · May 21, 2008, 09:34:07 AM

The rubber ring that frames the window does not leak. I know to clean them from time to time. I don't believe the hatch dogs have o-rings due to the connection to the window. The only area where a leak can occur is the bedding (I've looked closely using a flashlight to see if any seepage happens), the small gray gasket that joins the extrusion together at the bottom (same thing, no seepage seen), or the window gasket or o-ring if you will (that is clean and no water coming through)

tonywright · May 21, 2008, 10:09:08 AM

OK, reread your first message carefully. Based on your process of elimination, maybe the leak is starting higher in the coachroof, eg under a grab rail mount? If that is leaking, the water could migrate, and cause what you describe. I recall earlier discussions on lifting the grab rails and resealing.

Tony

sail4dale · May 21, 2008, 07:47:12 PM

I have poured water for hours on the port area and no leak. ON True Luff the water is migrating from elsewhere. I still haven't found out where .... ey!

Roc · May 22, 2008, 05:23:03 AM

Tony,
Good point, I'll check. However, in looking at the wood core, which is exposed around the frame, the top and sides look dry and clean. The bottom section, seems a bit darker and moist. The screw hole where I see water from is off to the side of the window. If the leak was coming from above, I would suspect the wood core around the window on that side would be moist; that is the section of core above the screw hole. The moist core is only along the bottom window frame.

Roc · May 27, 2008, 09:49:03 AM

The forward lower chain plate is right near the hatch, so I decided to see if that was the problem. I doused the chain plate, but found no water seeping into the screw hole (I first taped over the two through bolts on either side to only have water hitting the chain plate). I then removed the tape on the bolt heads and ran water right over the forward bolt. Like magic, water immediately seeped into the screw hole. Found my leak! I need to rebed the bolt. Hatch is ok. Did the same with other bolts, and found they are ok.

tonywright · May 27, 2008, 12:18:02 PM

Ah, logic prevails! That's why the upper holes were dry, and only the lower was wet. Congratulations on finding the leak!

This reminds me that the more experienced folks in our club recommend rebedding all thru-bolts etc on acquiring a new (to you) boat, and every x years (I'll have to go back and check the specifics). Apparently this can save all kinds of grief with wet cores etc. Another item for the to-it list.

Tony