any examples of side-to-side transferable water ballast sailboats?

Discussion in 'Sailboats' started by Squidly-Diddly, Jul 4, 2013.

  1. Squidly-Diddly
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    Squidly-Diddly Senior Member

    Any mono-hulls that get much of their sailing ballast from side water tanks that TRANSFER the water (or even fuel, or sewage) from side to side as a normal design feature.

    (yeah, I know sailors might on their own do this sort of thing on very long tack)
     
  2. Doug Lord
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    Doug Lord Flight Ready

    water ballast

    Yeah, transferable waterballast has been used a lot-particularly on larger boats-ocean racers. But from a racing standpoint canting keels won out because they allowed narrower, lower wetted surface boats like Wild Oats. Even Hydroptere uses water it places in the windward ama thru an intake on the leading edge of the rudder-no pumps!
    Why-what did you have in mind?

    Google: "waterballast in racing sailboats" I did and there is lots of info including some threads here.......
     
  3. sean9c
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    sean9c Senior Member

  4. keysdisease
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    keysdisease Senior Member

    The Hunter 54 or 60 of Thursday's Child record setting fame was water ballasted. This was a short production run vessel and I believe about a dozen were built. A friend of mine bought one recently and dumped the saildrive and anemic yanmar for a conventional shaft/strut drive.

    I have not sailed her but my friend says the water ballast system is very simple and stands the boat right up to a serious wind.

    Was way cool, the boat is a beast of 80's racing technology, fast is still fast

    Not my friends boat, but similar:

    http://dolphinspirit.org/thursdayschild.html

    Steve
     
  5. capt vimes
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    capt vimes Senior Member

    i am not sure, because it is not mentioned, if the OP is looking for racing boats or (fast) cruising sailyachts...

    german yachtbau is utilizing the mentioned features... there are 900 ltr water tanks on either side on the german 39 and 1400 ltr for the german 48...
    they claim to bring the full 900 ltr on the 39 around in a matter of seconds...
    http://www.german-yachtbau.de/germanseries_uebersicht.html
    sorry - do not know and did not find an english site... you might have to use the google translater...

    for racing yachts...
    as mentioned - canting keels is the way to go although they still have some quite large ballast-tanks - thinking now of the bigger ocean racing classes like IMOCA 60, 50, 40, VO 70 and such...
    but those tanks are placed deep in the hull along the centerline in order to trim the boat longitudinally...
     
  6. michael pierzga
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    michael pierzga Senior Member

    Fresh water ballast stored in under sheerclamp wing tanks is a nice idea. You gain increased tankage when the boat is sitting on anchor and you have the possibility to trim your tanks to windward in sailing mode.

    Its a lot of fuss for a small boat. 2 or three hundred litres of freshwater in a tank to windward . under the sheer clamp, adds very little righting moment

    If you need added righting moment add lead to the keel
     
  7. capt vimes
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    capt vimes Senior Member

    i completely agree with micheal...

    besides - everything has its pros and cons...
    freshwater ballast for a cruising yacht
    pros:
    - added capacity at anchor
    - high placed tanks, fully loaded might also damp rolling at anchor?
    cons:
    - reduced stowage due to the excessive tanks to have any righting effect
    - the need to replenish consumed water at any time if you rely on their righting moment
    - even so the righting moment is still small due to the tiny leverage
    - in case of a capsize, water ballasted yachts tend to have a pretty stable position upside down
    - added points of failure (imo the best is to keep it as simple as possible)

    attached you find an image showing the placement of the tanks on the german 39... (from the bow area looking aft)
     

    Attached Files:

  8. Eric Sponberg
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    Eric Sponberg Senior Member

    I have designed a few boats with water ballast, the latest being the Globetrotter 66 which uses fresh water for the ballast in twin tanks each side.

    http://www.sponbergyachtdesign.com/Globetrotter66.htm

    On Bagatelle, there are also twin tanks, but they are for sea water only.

    http://www.sponbergyachtdesign.com/Bagatelle.htm

    One of the lesser-known but desirable features of water ballast is that they are quite helpful when the wind is really light. Usually, in such conditions, the boat sits upright and the sails slat back and forth without drawing any wind--you're basically sitting still becalmed. If you have water ballast, fill one side to cause the boat to heel, and the sails will hang to the low side and form a reasonable airfoil shape. These will draw better on what little wind there is, and you'll make at least some progress moving forward rather than sitting still rocking back and forth.

    Eric
     
  9. bregalad
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    bregalad Senior Member

    Last edited: Jul 5, 2013
  10. Eric Sponberg
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    Eric Sponberg Senior Member

    The popular notion of water ballast tanks really started to take off with the BOC Around the World Race in 1983. Phillipe Jeantot won the race with his first Credit Agricole which had water ballast tanks. A lot of the BOC and round-the-world racers had it after that.

    Eric
     
  11. sharpii2
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    sharpii2 Senior Member

    I always thought that water ballast tanks were a simpler, more reliable technology than canting ballast.

    It is possible to design the tanks so they automatically empty, if the boat capsizes.

    There is no remedy if the canting ballast strut breaks off.

    I always thought that movable ballast should be a minority portion of total ballast, say 1/4 to 1/3.

    The BOC, Around Alone, and Vendee committees didn't see it that way.

    No doubt, the canting ballast system makes for a faster boat than a shifting water ballast one. But if they were compared on a cost per performance bases, that probably wouldn't be so.

    Safety wise, it is much easier to design a shifting water ballast boat that won't fail, than it is to design a canting ballast one that won't.

    The canting ballast is vulnerable to three things:

    1.) mechanical failure of the canting mechanism,
    2.) structural failure of the strut (apparently the most common form of failure), and
    3.) massive strut and hull damage due to striking a shoal or other underwater object.

    The major hazards with a shifting water ballast system are:

    1.) the ballast ending up on the leeward side, encouraging the boat to capsize,
    2.) the ballast on the windward side contributing to a capsize, once the boat heels beyond 90 deg., and
    3.) the shifting water ballast tanks holding the boat upside down after a capsize, due to failure to empty on the high side, as the boat tries to right itself.

    IMHO, the second group of hazards are far easier to deal with than the first.
     
  12. michael pierzga
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    michael pierzga Senior Member

    Canting keels are ridiculous.... expensive, deep draught, space consuming, complex, fragile, high maintenance..

    impossible to handle a cant keel boat out of the water without a steel cradle.

    Daggerboards add to the misery

    Only a trust fund fool with deep pockets and long arms would go that route on a dual purpose boat.

    FRESHWATER Waterballast...properly conceived... is simple, cheap, useful and effective.

    I particularly like fresh water ballast because it gives your greater autonomy when cruising

    Speak to your NA about waterballst when conceiving a yacht.

    I recently saw a 50 footer by Chuck Paine that had fresh water ballast.

    Fast boat, intelegently concieved.
     
  13. Timothy
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    Timothy Senior Member

    I like Rodger Martin's Gray Wolf.
     
  14. gonzo
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    gonzo Senior Member

    Why freshwater? Sea water give the crew the opportunity to make the draft shallower by dumping the ballast. In commercial vessels sea water is commonly used.
     

  15. Squidly-Diddly
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    Squidly-Diddly Senior Member

    I'm thinking of 'fast cruisers' (30'-100') with bilge keels holding rows of batteries for 'fixed ballast'(although they could be jettisoned), and sea-water ballast tanks running on either side of central passage way, and about as high as allowed for reasonable bench/bunk height, and just past bilge keel batt access floor hatches, as permanent structural members.

    Probably end up with four tanks, fore/aft, port/starboard, with storage bins as the center of the (mostly) continuous structural member, so the boat could be trimmed bow and stern as well as for sailing.

    Each ballast tank would have fairly large diameter pipe (2"-6") connecting the tanks low for reasonably fast transfer of ballast by either pump or low pressure air. Each tank would also have large hatch on top into which a bladder could be inserted for holding fresh water(or even fuel) and the bladder/hatch would have small tubes running from top of hatch down into the bladder, for extraction and/or slow transfer (but mostly just extraction).


    The idea would be to have a boat able to easily add or subtract displacement(so I wont be a light boat battered by big water), carry huge amount of freshwater and/or fuel as required, or sail "hard" with fairly light displacement and 'aggressive' ballast transfer, while still shoal draft and with some righting moment safety factor from the fixed bilge keel battery ballasts.

    Also have considerable batt capacity for possible hybrid or just convenience, and able to settle on twin keels.


    I'll try and whip up a rough sketch later.


    PS - I've seen a few mentions of water ballast, but they aren't clear as to whether they are non-side to side like MacGregor or almost pure "rail meat substitute" like I'm suggesting. Mine would make the boat less righting if ballast not transferred on tack change.
     
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