DRAGONFLY Trimarans User Forum

I've owned this boat since 2000, and have had a rain leak which showed up on the aft top middle edge on the starboard side of the saloon bulkhead.
It started to discolor the wood and I was concerned about rot.
Multiple efforts proved fruitless, but after nearly 14 years I finally found the leak !
It was rainwater seeping under the windshield frame and dripping onto the main halyard where it goes into the tunnel.
From there, it dripped down, ran aft through the joint between the tunnel floor and opening for the lines (which the factory had overlooked and not sealed) and leaked onto the inner liner.
From there, it ran forward to the aforementioned bulkhead.
It also ran aft and dripped onto the galley counter top, seemingly coming from the companionway door.

I could write a book on all the other spots we resealed in an attempt to stop this leak...




Two leaks fixed for the price of one ! YAY !

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Congratulations, I am still fighting with the same problem. This is my 4th year so I have still long way to go...

Is the way to test this leak: take a dry day and pour water into the tunnel - and look for the result?

And where did you stop the water? And how?

The turning block at the mast was insufficiently bedded.
The lower mounting screws sit in a puddle.
The nuts on the back side weren't accessable and were turning with the screw. Argh.
I ended up drilling out a couple of access holes above the screws but under the aluminum cover to access the nuts. It was wet when I got to the nuts.
I made a threaded backing plate for the nuts as well.
Then I reinstalled the turning block, well bedded in 3M4200, re glassed the holes.

It still leaked just as bad as before.


Next, I sealed the tunnel outer seam with a piece of fake fur wrapped around a long dowel which was slathered up with sealant, and ran it back and forth in the tunnel.
I checked my work with a borescope camera which was purchased on ebay.


I still had the leak just as bad as ever.


Finally, after taking off the windshield for probably the tenth time, I put a small mirror in the tunnel and looked down and aft.

There in all its glory was a very mature growth of MOSS !!
I scraped it out with a bent piece of copper wire and cleaned it up with a shop vacuum and spray alcohol.
After letting it dry, I filled it with a couple of applications of 3M4200 using my finger.

It is FIXED !!!!!!!!!!!!!!!

It hasn't rained since I repaired the leak(s), but I removed and serviced the winches on either side of the companionway.

Both were insufficiently bedded, and after a week of hot sunny days it was wet below the winches.

I don't know if they leaked or not, but after servicing, they were reinstalled in a bed of 3M4200.