Holding Tank Upgrades

Discussion in 'Marine Plumbing and Sanitation' started by wavydog2018, May 14, 2019. Add this thread to a FAQ

  1. wavydog2018

    wavydog2018

    Joined Nov 3, 2018
    3 posts, 0 likes
    Catalina Cruiser - 27'
    Embrace US Huntington
    Hi Ms Hall - Read your latest book ( a Christmas present )- loved it - makes so much sense! In order to add a second vent line to the holding tank ( 1985 Catalina 27 - V Berth located tank ) , can an inspection port be added, to access the new thru bolted nylon vent fitting, ( and also to aid in cleaning the tank ), without causing tank failure during pump-out function ? Or can the new vent line be self-tapped into the tank at center line as you described ? I've located / eliminated most odors, getting to the end now. Thank you very much, Jeff ( on L. I. , N.Y. )
     


  2. Peggie Hall HeadMistress

    Peggie Hall HeadMistress

    Joined Dec 2, 1997
    7,199 posts, 713 likes
    - -
    US LIttle Rock
    Tapping into the top of the tank and using a Uniseal UNISEAL to create a new 1" vent fitting would be the best way to do it...put it at the bow end of the tank and run it forward to exit the hull about a foot below the toe rail. A threaded plug wrapped in plenty of Teflon tape will seal the existing vent fitting. And then replace the "vent" thru hull with a 1" open bulkhead thru-hull.
    As for an inspection port, install one if you think you'll need access to the inside of the tank, but cleaning tank is fairly easy without one.
    Glad you're finding my book useful!
    --Peggie
     


  3. wavydog2018

    wavydog2018

    Joined Nov 3, 2018
    3 posts, 0 likes
    Catalina Cruiser - 27'
    Embrace US Huntington
    Thank you Peggy, greatly appreciate the quick response. Can I assume a 1" reinforced vinyl hose can be used instead of PVC as per the Uniseal install guide ? Also, forgot to mention the current ' 5/8 " vent ' , is located in the anchor locker forward. I was planning a change to thru hulls, on each side of the bow, just below the stripe
    under then toe rail, as I don't feel enough free air gets into the locker, especially with the lid in place.
    Best regards, Jeff
     


  4. Peggie Hall HeadMistress

    Peggie Hall HeadMistress

    Joined Dec 2, 1997
    7,199 posts, 713 likes
    - -
    US LIttle Rock
    Not only does enough free air not get into the anchor locker, but a tank that vents inside the boat is illegal! USCG regs require that all fuel and waste tanks be vented to the outside the boat because fuel and methane are flammable.

    It's not necessary to run pvc all the way from the tank to the thru-hull...just a short piece to be a hose "barb" that will prob'ly have to be a 90. You can find what you need in the plumbing department at any big box hardware store. A single 1" vent out the bow one or two feet aft of the stem is all that's needed. We can figure out the exact location together one on one when you're ready.

    --Peggie
     


  5. wavydog2018

    wavydog2018

    Joined Nov 3, 2018
    3 posts, 0 likes
    Catalina Cruiser - 27'
    Embrace US Huntington
    I called Keith at Uniseal - the parts are on their way ! You're right about the USCG venting issue, and the 1985 Catalina 27 holding tank vent is in the anchor locker, isolated from the main area, but still venting into a ' common area ' that is not secure, hence the new vent relocation project. I just love tinkering to make life afloat better. Thank you for your help Peggy, as this project moves along. Pix can be available at completion if you'd like. Cheers, Jeff
     




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