inspection ports leaking

I just installed deck plates (aka inspection ports) on my Eastport Pram, and ona whil decided to fill the boat with water and to check if they are watertight.

Turns out, not at all! They were leaking quite a bit—as far as I could tell, between the flange and the bulkhead. I put a fair amount of silicone caulk in there, but perhaps not enough...

What woulod you guys recommend? Unscrew the flanges and add even more silicone caulk? Something else?


5 replies:

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RE: inspection ports leaking

   Assuming these are the screw attached. I'd take 'em off clean all that silicon off and reinstall with 3m 4200 or 3m5200 (more forever) . Those products are made for boat applications. I've used 5200 underwater for years.  Put the product under the flange between flange and deck. Screw holes too. On an area where you might one day refinish I'd use 4200. It stays soft. 


The other kind epoxys on. I doubt you used that one. 

The screw on inspection covers will leak sometimes when under water through the threads of the screw on covers but not "flowing". 

RE: inspection ports leaking

   Yeah, I used the one that are attached with screws. Would you still use screws with 3M 4200?

RE: inspection ports leaking

4200, yes.  For a good seal, screw down just until it squeezes out evenly.  After it cures a bit, tighten screws down some more.  With 5200, you might get away without the screws, but they are helpful for getting an even squeeze anyway.


RE: inspection ports leaking

   Thank you! Cleaning off the silicon turned out to be a big nuisance (I am avoiding using sharp tools). Any tips or ticks?

Other than that, I am going to try 4200.

Menwhile, feeling silly that I damaged a perfectly good boat...

RE: inspection ports leaking

   I use a five in one tool. Sharp not too much but effective. 

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