Old Marine Head: Could it be the Vent?

1981 diagram of sewage disposal system
1981 diagram of sewage disposal system

The more I think about the problems we’re having with the 40-year-old Raritan Cricket manual marine head, the more I think it is likely due to a plugged vent. Or at least one aspect is related to the vent; other issues may be caused by the extremely high amount of gunk on the inner workings of the toilet and the age of some of those components.

(The previous owner passed away last year. As I become more familiar with the boat, I’m recognizing signs that for the last few years, he may not have been able to give Swoose his usual care and attention. The toilet is one of those things where it has sat idle for too long. A marine head is one of those things that does need to be exercised to keep things moving along!)

With the deck pump-out fitting removed, I can cycle the pump handle. After replacing the fitting, the handle stops working completely after several strokes. It won’t go all the way up. I’ll test this again this week when I’m at the boat by removing the fitting again and seeing if that frees up the handle. My guess is that it will. And in fact, since I think this is one of the root causes of the problems with the head, I went ahead and ordered a new vent, new vent hose, and new clamps from Fisheries Supply.

If the vent line is preventing the toilet from working and replacing it solves that part of the problem, then the next task is to clean the nasty buildup of gunk in the toilet. It’s entirely likely that the tank did not get pumped out completely because of the plugged vent, and I’m lucky that the tank did not collapse! In addition to cleaning the toilet, I’ll probably need to get the holding tank pumped again after fixing the vent problem.

So:

  1. Fix the vent, test wet and dry cycling of the toilet.
  2. Clean the toilet so that the flapper valve can function properly, test to see if that allows the bowl to be completely cleared.
  3. Pump out the holding tank.

If those steps resolve most of the issues with the old marine head, that will remove the urgency of replacing it. (Although I do have a new head due to arrive this week!) That will also give us time to clean some of the gunk that has built up inside the holding tank, a necessary step before we have the old, cracking pump-out hose replaced. That work is part of the punch list of items to resolve by a contractor in June.

Resources

Besides my own books, I’m also reading this resources found online:

Update April 9, 2022: Photos

We visited the boat today to track down the location and condition of the waste vent hose. The vent through-hull fitting is so badly corroded that it appears to be almost 100% blocked. I’ve purchased a new vent fitting, and while I’m at it, I’ll replace the hose with new 5/8″ hose more suitable for the holding tank vent.

svnarwhal icon 128px

One thought on “Old Marine Head: Could it be the Vent?

  1. Tom

    Second pumpout of the holding tank today. I have to say it was very satisfying to hearing the air rushing into the vent fitting while I evacuated the holding tank. That sound was previously absent because the old vent was so corroded as to be almost completely plugged. Everything went without a hitch once we figured out which switch on the dock to activate!

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