Batteries in the bilge?

Discussion in 'Boat Design' started by Squidly-Diddly, Oct 25, 2007.

  1. Squidly-Diddly
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    Squidly-Diddly Senior Member

    Years ago I took a vow that if I ever designed a boat with any kind of ballast....that ballast would be in the form of heavy batteries, and thus serve at least one other purpose.

    One advantage of using a group of standard auto/marine batteries of ballast is that the amount of ballast could be adjusted.

    Of course having a bunch of batteries at the lowest point raises a few issues of its own.

    1) How to keep the connections from being flooded if even a small amount of water is taken on.

    2) How to vent any fumes (assuming design is able to use ANY type of battery that might be found in distant ports, mostly from vehicles).

    3) How to handle leakage if the battery's case(s) are breached and you are faced with several gallons of battery acid in the bilge/battery compartment.

    4) How to secure the batteries in the event of full-on capsize to they don't start causing massive damage of their own and in a related subject.....

    5) How to service and replace them.

    What about a sailboat with a bulb encasing batteries at the end of a daggerboard? I've seen bulbs of 300lbs on the end of daggerboards.

    To service the batteries you would "Just" need to drop the bulb/board into shallow water by the dock, haul the unit up, and open the watertight nose cone.

    Before dropping a string with a float would be tied to the support cables/wires.

    Not sure how to re-install. Maybe make sure that a string long enough to allow for the operation runs through the top of the daggerboard case. Or just drop a weighted string through the top and snag as it hangs under the boat with a pole and hook.
  2. Raggi_Thor
    Joined: Jan 2004
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    Raggi_Thor Nav.arch/Designer/Builder

    I would put the batteries an a movable case and move them from side to side at each tack :)
  3. Squidly-Diddly
    Joined: Sep 2007
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    Squidly-Diddly Senior Member

    Movable ballast was my next topic; but using water.

    Australian company is marketing a yet to be built, large fast motor sailer that shows lot of water storage/ballast in side tanks.

    A MacGregor SHOULD be able to drain/fill the water ballast tanks(as in separated, not just one tank) at least 'port of starboard').

    I'd like to keep a "permanent ballast" of lead/acid batteries as in the keel/shoe of a 26M but be able to pump all the water ballast from side to side.

    I'd also like to be able to use the pump to dump water ballast and turn the tanks into floats by any of at least the following: elec. pump, low pressure compressed air, manual pump or external suction pump hose.

    I'd dig up an old email of a boat for sail like this, aprox. 40+', made by a 'homebuilder' for trans-Pacific sailing.

    But, I do think that a slidable battery pack is very feasible in a wide range of mono and multi hulls. Just make a box that rides on a couple tracks regulated by a couple ropes.

    I can see everything from 4 batteries in 2 boxes fore and aft of the mast/daggerboard case in a open boat to a lead ottoman in a big, beamy yacht. I think being able to tie it securely but still able to slide it is the biggest problem.

    I'd try to get the ball rolling by making sure the box could be used for other storage while still serving as movable ballast. I'm not in the business of selling batteries, per se, box could also be a water(preferably potable, washable fresh water) tank of the same size on same tracks, or store bought 1 gallon jugs.

    As far as the actual rigging and structure-I'd just make sure the thing was rigged so that it would slow down and slightly tighten snug when being transfered.

    I think this concept could be retrofitted, espeically in a mild and cautious degree, to many existing boats.

    Just need to figure out what sort of track. I'm thinking of a sliding(no wheels) able to be fairly easily pushed and mechanically 'locked', but with ropes and tackle as back-up.
  4. rwatson
    Joined: Aug 2007
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    rwatson Senior Member

    I dont know why your are worried about spillage and fumes - fully sealed gel batteries are almost standard fare on yachts these days. In fact they are mandatory for ocean racers.

    For all their weight, they are hardly worth all the effort- even four batteries doesnt weigh as much as a hefty crew member - and crew move themselves quite quickly.

    The water ballast concepts are worth working on, but sudden wind and wave shifts present dangers. A sudden gybe or knock down with a few hundred kilos of water on the wrong side could upset things a bit.

    Who is the Australian company building the motor sailers by the way ?
  5. Squidly-Diddly
    Joined: Sep 2007
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    Squidly-Diddly Senior Member

    rwatson, can't recall but someone was knocking their

    projected sailing/motoring/equipment weight VS speed promises.

    They have something similar to a 'saildrive' but it folds up into the hull for sailing. Also, a drop keel of some sort.

    I do remember it was 800-900 hp to get the boat up to 20+knots.

    Seemed to be sort of like a massive MacGregor in many respects.

  6. Fanie
    Joined: Oct 2007
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    Location: Colonial "Sick Africa"

    Fanie Fanie

    I agree with rwatson.

    The sealed lead acid (SLA) batteries are the battery to have on any boat. The best way to mount any battery in a boat of any sorts is on foam rubber to act as a shock absorber, tied down properly, safety belt straps with proper quick release clips should work fine. These batteries won't spill even when turned upside down.

    Take note they are charged different from lead acid (LA) batteries and charging has to be voltage and current limited for the size battery you use.
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