Neoprene Gasket for holding tank Inspection Plate

[bigmuffin]

Hi, Unfortunately, I've had to open the inspection plate to my holding tank a few times recently. The inspection plate is a round metal piece laying on another raised metal piece (which allows me to tighten all bolts from both sides) which I think is fibreglassed onto the top of the tank. There are bolts around the outside of the inspection plate.

There is a rubber gasket sheet that sits between the two metal plates. Since it is about 25 years old, I figured I might as well replace that while I am doing everything else.
I was going to use some neoprene gasket material which I think is similar to what is on there now. I found some at go2marine.

My question is if I need to put of grease or lubricant between the neoprene gasket and the metal above and below the gasket where it is tightened? If so, any suggestions on brands that are readily available that would work? I have done some searching and read conflicting advice on what to use and what might harm a neoprene gasket. Does the lubricant provide an extra seal or just protect the gasket when it is taken on or off?

Thanks!
Marty

 

[Peggie Hall HeadMistress]

No lubricant needed for that application.

It really doesn't do either one.

Why in the world have you found it necessary to open that port, not just once but a FEW times??? That's something that shouldn't happen, so methinks we need to figure out what you're doing wrong or not doing that you should.

 

[bigmuffin]

Re: No lubricant needed for that application.

Yeah. All problems related to pumping out the head. As new owners of an older boat, we had some confusion about what problems we were having since nothing was pumping out. Open the port to see an empty tank and realized we were pumping overboard. Then realized the hoses from the head to the holding tank were pretty much clogged after 20 years since it immediately became almost impossible to pump into the holding tank. Had some of the hoses replaced to correct this. Those hoses were very heavy...

The other time was again when we were having problems pumping out. Cleared the vent and it seemed to help but not completely. Just seemed like it was not pumping out as much as we would expect. Opened it to find we sure were not getting most of it (there is not tank monitor or way to really know).

Works better now, but as the hoses now seem to be smelling after the years I am planning on replacing the rest of them. Also want to put a diverter valve on between the holding tank and the pump out to replace the current y-valve. That y-valve is attached to hose that goes to the back of my boat where there is a manual pump out. I suspect that there may be sewage sitting in that hose that may also be an issue so I would rather not send anything into that hose unless we truly need the manual pump out.

Thought I would put a fresh gasket on there while replacing the rest of the hoses since we are going through all the work of flushing the tank clean before this all happens.

Thought about installing a tank monitor as well while this was all happening so I hopefully wouldn’t have to open it again. I don’t think the external sensors would work with the thickness and construction of the tank.

 

[thinwater]

Yes, neoprene is rated for both grease and sewage. Yeah, the grease should make it easier to peal the gasket, but really no other purpose. Sometimes people grease a gasket to stick it in place (but only do that with oil-resistant materials).