Fixing Leaky Thru-Deck Fills

We are three short weeks away from our (hopeful) June 1st departure and we both are wondering how we will make it all happen. On the plus side we are almost done with all the major leak repair work.

One of the major source of leaks on the boat were the port side thru deck fills/hardware. We have three of them for diesel, water and holding tank pump out. They have leaked so bad over the years that they not only rotted out one of the internal bulkheads but also caused the fiberglass tabbing in those locations to pop off the hull. Sometime in March we put a large cooking pot beneath the diesel fill thru-deck to see how much water we would collect in a period of one week. We couldn’t believe our eyes when we collected almost the entire cooking pot which would be about 1 gallon in just over 7 days.

As usual, we were un-pleasantly surprised when we started investigating the situation. The hardware was simply screwed onto the teak with a bit of polysulphide below. We figure water was entering from this interface, as well as getting beneath the teak planks and entering at that interface and finally of course from the soggy core which was wet from the teak deck leaking screw holes. See diagram below of original leak points.

Leaks from thru-deck hardware before remedial action

I wanted to remove the crappy small screws into the teak deck and instead thru-bolt the hardware on a new solid fiberglass disk. I brainstormed with Peter the previous owner and he instructed me on how to build the disks by wrapping fiberglass around a PVC pipe. Our “mould” cost us $0.69 and we used car wax as the release agent once the fiberglass had cured. I then cleaned the old teak around the thru-hole so I could bed the new fiberglass disks and epoxied them in place. I also removed the old wood in the core around the hole and filled with thickened epoxy. Finally, I thru-bolted the entire assembly and bed in butyl tape. I have a new-found love for Butyl tape as a bedding compound. It’s relatively inexpensive, easy to work with and will last longer than our boat. You can read a great description of why and how to use Butyl tape here. Below is a sketch of the new installation. I have vowed to Saxony I will eat my dirty shorts if these thru-decks leak during our trip!

Final install! I'll be keeping my undergarments extra clean just in case.

 

The old hardware was screwed in to the top teak planks.

The old hardware was screwed into the top teak planks.

PVC pipe mold and car wax as release agent. This was a first for me and worked out perfectly.

PVC pipe mould and car wax as a release agent. This was a first for me and worked out perfectly.

Fiberglass wrapped around the mold. I colored the epoxy black thinking it would look better on our deck but in the end you can't see it at all so that was a waste of black pigment!

Fiberglass wrapped around the mould. I coloured the epoxy black thinking it would look better on our deck but in the end, you can’t see it at all so that was a waste of black pigment!

Fiberglass mold after first cut. I then cut three 1/2" thick disks. These will last literally forever.

Fiberglass mould after the first cut. I then cut three 1/2″ thick disks. These will last literally forever.

Disk in place in one of the three thru-decks. These were then epoxied in place.

The disk in place in one of the three thru-decks. These were then epoxied in place.

Hard at work. No wonder my back and knees are killing me

Hard at work. No wonder my back and knees are killing me

The complete thru-deck with wet epoxy prior to disk being glued on

The complete thru-deck with wet epoxy prior to the disk being glued on

Ta-da! Finished project!

Ta-da! Finished project! I’ll be keeping my undergarments extra clean just in case.

 

 

 

 

4 Comments

  1. Thank you for the photos and schematics. I will be soon repeating the same exact work on Carmela.

    • Glad this helps Andrea. Discussing with Peter the previous owner we now are both of the opinion that the colloidal silica I used to thicken the epoxy for “potting” the opening may have made the epoxy to hard and rigid and boat flex could cause failure. For this reason we recommend Thickened GFlex epoxy. Good luck and send some pics!

  2. Somehow you guys make the worst jobs look glamorous! Think it must be the black pigment. I won’t tell Jon about it or every future epoxy project we do will have to have some fancy colour 😉

    • Haha thanks Leah! I wish doing the jobs was as glamorous as they may appear online! 🙂 We work with black and white pigment as needed. But we learned the hard way, never add more than 10% pigment to the mix or risk a soft epoxy that never fully cures. And then you are hooped!

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