Water Ballast for small boats

Discussion in 'Stability' started by Toot, Sep 24, 2006.

  1. bigshrimpin
    Joined: Nov 2004
    Posts: 4
    Likes: 0, Points: 0, Legacy Rep: 9
    Location: Davis, CA

    bigshrimpin New Member

  2. Claus Riepe
    Joined: Sep 2006
    Posts: 70
    Likes: 1, Points: 0, Legacy Rep: 9
    Location: Germany

    Claus Riepe Junior Member

    Yes, interesting. Waterballast for stability, and at the same time used to improve trim during acceleration and deceleration, in a fairly simple way.
    Has the system ever been used in a commercial craft?
  3. rotfix
    Joined: Oct 2007
    Posts: 19
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: austin

    rotfix Junior Member

    wakeboarders use ballast similar to what i'm reading here. there's also a company with a patented system in production...calabria...patent # 6234099

    they have a bladder under the deck and inlets on the transom which are under water when at rest. open the inlets to flood the bladder. get the boat on plane and the inlets are out of water, open to drain. i'm not sure if there's an over-flow line too.

    another variation i've seen is to use the vent as the control as was mentioned earlier in this thread. this was done with a baldder above deck. if i remember, a scupper was on the bottom of the hull to force water into the bladder at speed. the vent was opened to evacuate the air. close the vent to hold the water. at rest, open the vent and the bladder empties.

    these are somewhat different though since the first requires planing speed and the second requires a bladder or tank on deck. hope this wasn't posted already, i did a quick scan.
  4. rwatson
    Joined: Aug 2007
    Posts: 5,880
    Likes: 312, Points: 83, Legacy Rep: 1749
    Location: Tasmania,Australia

    rwatson Senior Member

    Toot -
    Good to see your mind is in top creative health to come up with a good idea, but .. its already 'standard fare'
    The Macgregor system works fine with no pumps and doesnt need forward facing holes or any of that stuff (speaking as an ex owner).
    Yachts have been using perfectly adequate water ballast for years now, its all been done. Pumping rates are not a problem.
    Anything under 30 ft ( down to 2 feet) is no big engineering feet - it works, its straightforard, its not even news.

    But here is a twist for you - how about a flexible 'bladder' inside the water ballast container to hold fresh water for the crew. As the fresh water gets used, it is replaced with salt to maintain the ballast.

    Keep those creative juices flowing.

  5. doug kay
    Joined: Oct 2007
    Posts: 25
    Likes: 0, Points: 0, Legacy Rep: 3
    Location: Florada USA

    doug kay Junior Member

    It sounds a good idea and it's something I considered for my Ground Effect catamaran but the extra weight you add to make the container defeats the purpose.
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.