Inspection/acces port for water tank recommendations

[hlev00]

I have a fiberglass water tank in the bow of a Beneteau. The tank has a 10mm or so balsa core. It came with no inspection ports so I added a Beckson screw type access port. The tank is under the v-berth. I installed the port on the starboard half of the top of the tank. Today on a beat on port the top started leaking past the gasket of the screw in lid presumably too much head pressure.

Any recommendations for a better access port for this application?

Thanks,
Harry

[tkeithlu]

It sounds like the problem is the o-ring around the cap. The pressure involved, a foot or inches of water depth, is so small that it should not leak. But then, it is leaking. That o-ring is easy to cut with sand and by tightening it too much. I've done both at one time or another.

Step #1 is be sure that the leak is at the o-ring, not around the edge where you glued the frame to the tank.

Step #2 is replace the o-ring. Here's a source:

https://www.tackledirect.com/beckson...By8KLheHFdS5c-

Step #3 involves soft silicone on the o-ring, or even on the threads.

If it's still leaking after all that, I think I'd be so frustrated as to begin wondering whether I needed an inspection port there in the first place.

[hlev00]

Definitely from the lid, not the flange. First attempt, the surface was not flat so the flange was twisted a bit. Second attempt no movement before silicone and screws. The water seeped past the gasket.

Pretty much the conclusions I arrived at too. Still hoping to find a different port for a final try if the super lube doesn’t work. Most others seem to be for a thin wall poly or sheet metal tank.

Thanks,
Harry

[tkeithlu]

I didn't really think about the possibility that the frame was bent. The o-ring wouldn't have much of a chance in that case. One way to avoid it would be to glue the frame to the tank with the cap in place, so the cap keeps the frame flat.

[hlev00]

Good thought. I think I did this the second time. Maybe a 3rd try is in the future. I agree, that the problems are starting to outweigh the benefits but I needed it at least to give it a good cleaning as the water was getting funky and bleach shock treatment was not enough.

[hlev00]

A note from Beckson support "We do not test to a specific pressure but the ABYC standard is to resist water pressure to 12"without seepage of more than 0.25 fluid ounce per hour."


We were seeing about 1 oz per hour. Still in conversations with Beckson.