Sealing an outlet from the holding tank

[David]

Hello.I'm giving up on the y-valve and going to a holding tank only system. I am left with an outlet in my holding tank I don't need anymore, and want to seal it up. It's not threaded. My plan is to use a 1.5" threaded cap and to seal the thing in there with 5200.I am wondering if this will work and whether thesealant will contain the odor from the tank.

 

[Peggie Hall/Head Mistress]

DON'T use 5200!

Or ANY permanent sealant...the next owner may want to put that port back into service (think about all the things the builder provided no access or ability to change without taking a chain saw to the boat...and don't add to the next owner's problems!)You say the fitting isn't threaded...is the tank metal or plastic? And is the fitting a female port or a male nipple?