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Head Smell - solved (New Vent Hose and HTVF)-gctid758880

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    Head Smell - solved (New Vent Hose and HTVF)-gctid758880

    After putting up with an awful smell inside and outside the boat every-time the heads are flushed for the past year, I resolved to track down the origin. My boat like many of ours has older white sani-hoses, mine of indeterminate brand. I initially thought I would be replacing all these hoses, since there were no leaks at any connections - so the smell must be coming from the hoses I thought. I blew through the holding tank vent and there was no blockage there.

    After reading tips on this site for making a HTVF Holding Tank Ventilation Filter I assembled the necessary parts and made up a very cool looking 12" X 2" diameter filter. I planned to cut this into the existing hose, see what the result was then if needed replace other hoses till the odor went away.

    As I scoped out the installation of the vent hose I could see it was liberally caulked-in to both the tank top and the through hull fittings. Odd I thought, and noticed that all the sani-hoses were caulked in so perhaps not so odd.

    After a bit of a struggle with the odd angles and the caulk I was able to free the vent hose from the through-hull - to find that the hose is a 3/4" hose fitting into 5/8th barb fitting. Hence the gobs of caulk. It quickly became apparent that the hose was not sealing, at least at the through-hull end and possibly in the engine room, although I have never noticed a head smell there.

    Long story somewhat shortened. I replaced the vent hose with a correctly sized 5/8" hose and a new through hull vent fitting. Hooked up the homemade HTVF and Voila! No more head smell. I could not find sani hose in the correct dimension so this may be a shortlived repair. If the transparent reinforced hose starts deteriorating it will be relatively easy to replace.

    I put the old dry hose in my SUV to take to the trash and it quickly stank up the entire vehicle.

    I still need to replace the old liquid sani-hoses and have put that on the winter maintenance list.

    I chose to install the HTVF in the bar cupboard rather than behind the bar back wall simply for ease of charcoal replacement. (the hatchet job on the other hole in the photo is a PO's work!)

    Alan Teed
    1996 Wendon Sky Lounge 72'
    Gig Harbor, WA
    1994 Bayliner 4788
    2006 Hylas 49' SY
    Bayliner 2855
    1977 Cal 34' SY
    1981 Hunter 33' SY
    Experience: Sail 50 years, Motor 15 years. 2 Transats, 1 Baltimore-Virgin Islands, 6 Months cruising Caribbean, 3.5 years cruising Med.

    Thanks for the follow up. I am two days from installing one myself.
    1992 3288, twin Hino 150's sold
    S. Puget Sound


      I used 5/8 fuel line,odor can't get through it,going on 2 years now.


        I have to do a hose replacement but it is routed under the molded in shower. I have no idea how that's going to work out.