Water Ballast Pickup Question

Discussion in 'Multihulls' started by edvb, Jan 28, 2009.

  1. edvb
    Joined: Mar 2008
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    Location: Oshkosh,WI

    edvb Junior Member

    I installed a water ballast system in my Ama. I have a streamlined pickup going straight to a 500 GPM Tsunami Aerator pump. From the pump I have a one way flap check valve mounted horizontally right out of the pump and a hose connected to it and going to a ballast bag top fitting about 8" higher than the intake on the bottom of the hull.

    The question is will I still have some water pressure going over the intake going through the pump ,Check valve and filling the bag without the Pump on when sailing from 0 to 16 knots?

    Or with the 6" water column pressing against the one way check valve be enough to prevent any more water entering the bag?

    The bag is vented.

    It is all installed but I cannot test it till spring.

    Any help would be greatly appreciated.


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  2. sailor2
    Joined: Jan 2009
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    Location: Europe

    sailor2 Senior Member

    Sorry, can't help on your questions.
    But the last pic causes some questions.
    Is your beams of metall, and if so steel or alu or ?
    The end fitting for the lower tube on forward beam near ama seems to cause local bending on upper tube, since the tension of the lower tube doesn't extend all the way to transfer the load to upper tube wall as compression. If that's the case instead of just wrong impression from the pic, it's really scary structural engineering or heavy if the fitting is large enough. What's the idea behind that ?
    Since you are using water ballast in amas, it's quite loaded up already and I would like to see something strong in there and hopefully light as well as using ballast indicates performance targets being high.
     
  3. edvb
    Joined: Mar 2008
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    Location: Oshkosh,WI

    edvb Junior Member

    The bottom tube supports the bruce foil. The tubes are aluminum and no problem supporting the loads I have.

    There must be some engineer out there that can answer the question I asked in my post. Help me out here please.
     
  4. TeddyDiver
    Joined: Dec 2007
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    Location: Finland/Norway

    TeddyDiver Gollywobbler

    For sure some but.. becouse of the shape of the intake it's answered only after testing.
    To make a quess, for me it looks it's possibly some amount of suction at speed. It can be a minor change in the shape to make the difference. However the sharp turn around the intake makes a lot of eddies...
     
  5. PortTacker
    Joined: Nov 2008
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    Location: Oregon USA

    PortTacker Junior Member

    Yeah, why didn't you build it more flush?
     
  6. edvb
    Joined: Mar 2008
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    Location: Oshkosh,WI

    edvb Junior Member

    Porttacker

    The pump is not self priming so I had to make sure it was low enough.

    I decided to install a valve and clean up the wiring to the switch at the same time.

    T & H marine sent me a sample full flow ¾” plastic remote valve they use on boats for a remote drain valve on a livewell tank.

    I installed the remote valve right after the one-way check valve connected to the discharge port of the fill pump.

    I shortened the cable and after everything was installed the control to open or close the valve works very smoothly.

    I install it along with a black Flex-A-Rail that is used for awnings where a boltrope fits in the slot to hold the fabric in place. The slot was just big enough to snap the remote valve cable in followed by the switch cable. It fits very snug and when I need to disassemble the boat the cables can easily be pull out of the slot in a matter of seconds. No ties or tape and no fuss.

    I really wanted to make the system as inconspicuous as possible yet make it bulletproof at the same time.

    I cannot wait to test it sailing and hope it will work according to plan.
     
    Last edited: Feb 7, 2009
  7. edvb
    Joined: Mar 2008
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    Location: Oshkosh,WI

    edvb Junior Member

    Valve installed

    Hi All

    Thanks for helping me out on this. Here are some pictures of the completed installation. What do you think?

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    [​IMG]
     
  8. sigurd
    Joined: Jun 2004
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    Location: norway

    sigurd Pompuous Pangolin

    Beautiful boat - except for the intake fairing looks draggy. I have open centerboard trunk in one of the Tornado hulls, I can feel the drag from it since it varies and there is slapping sounds accompanying the decelerations. And this is probably a 300kg boat, all up.
    What is the hull in the background? Was this a tri before?
    How did you make the bent foil?
     
  9. edvb
    Joined: Mar 2008
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    Location: Oshkosh,WI

    edvb Junior Member

    Sigurd

    I have not tested the boat with the bottom fairing so I do not know if it is draggy or not until I test it. I try to do the "walk before the talk" and it has served me well. The other hull is my backup if this experiment fails. So long I can paddle easily at 2.5 -3.5 knots and roll out the sail and have it be effective at about 4 knots true wind speed I will be a happy camper. I think Chris "O" understands where I am coming from as it is tough to design a boat that will achieve all the goals I want in a boat. In the next month I will find out if it was worth it or I need to change it out with the Ama without the internal ballast system installed you see hanging above. If it works the way I want I have a mini Hydrofoil/Water Ballast stabilized outrigger sailing canoe that will be the "cats meow" in terms of performance for me. Pull the daggerboard up release the rudder down haul and I am cruising in about six inches of water. "Go Ahead make my day" ha ha. The only boats that will out point me is maybe a "A" cat or a IC canoe size wise. I crewed on a A scow so we won't go there. "Foils do not have to always lift to gain speed"
     
  10. edvb
    Joined: Mar 2008
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    Location: Oshkosh,WI

    edvb Junior Member

    Sigurd

    About 158 kg all up with my body weight. I weight about 87 kg so the boat is pretty light, It is all carbon and with all the modifications I installed it is pretty bulletproof. Originally the boat weighed around 45 kg. I added some layers of carbon in the main hull and did some other major modifications. I do race it and in the three years I owned it I never had any failures in all the systems.

    You can check out what I did here. Just go to guests and clik on EddieVB.

    http://www.raptor-uk.net/
     
  11. edvb
    Joined: Mar 2008
    Posts: 59
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    Location: Oshkosh,WI

    edvb Junior Member

    Raptor 17.5 Expedition

    Hi all

    Here is the latest development in my Raptor. The sail had to be reduced so it would balance the CG and still have power. You all gave me food for thought and this is the end result.

    Well I finally got a video online. I was a little nervous as the water is still
    very cold and I did not want to flip it. All the tests are without using the
    foil and only using the active water ballast system and the reefing system.
    Everything works great and I did not need to lean on the side car as shown in
    the video but I need to break that habit. Winds were 15-16 MPH with many
    gust's. Maintaining 9-10 knots was easy once I reefed and the boat was as fast
    if not faster in that configuration. As you can see it is a very dry boat and
    you can almost see me grinning in not the best of conditions.

    I went out today in 5-10 MPH steady winds and it was perfect. The ama lifted out
    of the water and I added 1/2 a tank of ballast to balance it out with full sail.
    So far I am equal in speed on both tacks. I have a 90-100 degree tacking angle
    while not great but all the telltales are flying and she is powered up when
    testing at these angles. On a starboard tack the ama rises smoothly and I had my
    best speed without using the foil and balancing the sail load with the water
    ballast. Hope you like it.

    http://www.youtube.com/watch?v=gHR7mg5LBz0
     
  12. captainsideburn
    Joined: Mar 2009
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    Location: Tasmania

    captainsideburn Junior Member

    sweet how fast you going?
     

  13. edvb
    Joined: Mar 2008
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    Location: Oshkosh,WI

    edvb Junior Member

    Around 8.5 - 10 knots.
     
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