Ice class/Icebreaker hullshapes?

Discussion in 'Powerboats' started by catweaselcat, Mar 5, 2006.

  1. catweaselcat
    Joined: Nov 2004
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    catweaselcat Junior Member

    Hi,

    I have a small 30-40 m concept project in mind and would like to have some input on hullshapes useable under ice conditions.

    Does anyone have access to a typical set of lines for an icebreaking vessel? I am not so much after a real icebreaker, which should make a maximum wide channel, rather then after a vessel able to make her own way under moderate ice conditions.
    I'd guess for a ship of this type, the hull could be more narrow than a typical icebreaker.

    Does anyone have info/linesplans on double acting icebreaking hullshapes?

    I will draw the preliminary hullshape myself, do the prel design work on that base and then use experts advice to optimize...

    Thanks,

    Charlie

    K.v.B.@gmx.net
     
  2. Robert Gainer
    Joined: Jul 2004
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    Robert Gainer Designer/Builder

    Small boats don’t make good icebreakers. Some icebreakers works by riding up on the ice and then pumping water into forward tanks to break the ice and drop the bow. To keep a channel open they work back and forth to widen the channel. A ship cannot usually just follow an icebreaker unless the ice is relatively thin. Add to this, in heavy ice the icebreakers work in pairs to open a channel and keep it open. A small boat does not have enough inertia to keep moving in ice. I have worked a small icebreaker and once found myself on top of the ice after getting a running start and we sat on the ice until our barge and crane came over, breaking the ice with a pile driver by dropping the hammer onto the ice. I also think a narrow boat will get caught in the ice. A wide boat can twist and work on a new angle of attack when breaking ice. A narrow boat can only just keep hammering away on the same course. And of course the narrower boat does not have the greatest weight and that brings you back to a lack of inertia and power.

    But you know what they say; a new idea is always greeted with ridicule.

    To answer you question directly, the profile of an icebreaker is normal except for a cut away at the bow much like a ramp to ride up on the ice. The bow is also wider then normal to accommodate the water tanks for ballast.
    Robert Gainer
     
  3. kach22i
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    kach22i Architect

    You might want to restore a surplus/retired govenment Ice-Breaker, save it from the scrapyard - buy at auction.

    Your obvious alternate would be a hovercraft.

    Hovercraft can fly over the ice or can be used as a Ice-Breaker. The way that would work is a small amount of water is depressed/displaced under the ice creating a cantilever of ice, which breaks under it own weight, and because lack of sheer strength.

    An alternate is to combine the two concepts. A hover-platform to the front/bow of a ship.

    Like this:
    http://www.hovertrans.com/ice_breaker_ship.htm
     
  4. safewalrus
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    safewalrus Ancient Marriner

    And if that wasn't enough, don't forget the extra heavy scantlings! that hull needs to be S-T-R-O-N-G, obvious really, but it has been forgotten before! :)
     
  5. Wellydeckhand

    Wellydeckhand Previous Member

    Serious guys the icebreaker hull is different from hull of other ship........:D:D:D I ahve pics but cant find way to post it on threads...... I ahve tonnes of mag sitting on my laps....:(
     
  6. kach22i
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    kach22i Architect

    Don't worry, we won't tell anyone of your fetish.

    I did a quick Google image search "icebreaker hull", seemed to me they have much in common with a Tub-Boat hull.

    Sure enough, one of the links said: MS Rygene is in daily use as a harbor tug and icebreaker in Arendal in the southern Norway.

    Link:
    http://www.tmbk.no/eng/ryg1en.htm

    Is it possible to use a strong tug hull to break thinner ice?
     
  7. Gilbert
    Joined: Aug 2004
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    Gilbert Senior Member

    Here is a link to a museum vessel "Aarvak" in Norway. It is in the size range you are mentioning. These types were quite good in the ice, but not heavy duty icebreakers. www.ishavsmuseet.no
     
  8. Wellydeckhand

    Wellydeckhand Previous Member

     
  9. catweaselcat
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    catweaselcat Junior Member

    @wellydeckhand, bit crazy, are we. Please lets not ridicule this thread. All others just ignore comments like the last one.

    @gilbert I'll send a mail to the museum, thanks

    @kach22i I am after a hull which can also work in ice reasonably well. The hovercraft concept does not work for my application....

    @rob, thanks, I know that the hull has to be strengthened and all that, what I am after is the actual hullshape. So reasonably wide & maybe with an icepicker & hammer. Possible ballast tanks. Its obvious that smaller ships wont make great breakers...

    So anyone with a set of lines? Please?

    Best regards,

    Charlie
     
  10. Wellydeckhand

    Wellydeckhand Previous Member

    I apologies if any taken offend........ it was off the thread and not mean for u................:)
     
  11. kach22i
    Joined: Feb 2005
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    kach22i Architect

    I was not offended, knew you were just joking back Wellydeckhand.

    I would of used a smile face in my other posts to help express that, but recent changes in the forum have adversly affected one of my browsers.

    I still think a tug boat hull or other non-planing hull (say slow and stable) is the general direction.

    May there always be room and time for a quick joke in this forum.;)
     
  12. Guillermo
    Joined: Mar 2005
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    Guillermo Ingeniero Naval

    I agree.

    An small boat what need is to have an strong hull (As Walrus states), able to resist pounding from ice as well as pressure if getting trapped. Vertical sides are not recommended, although an small boat will probably don't have them anyhow.

    I suggest you a visit to
    http://www.vagabond.fr/vagabond
    Very much in the line Robert Gainer says, Vagabond has an icebreaker style bow and a very particular hull profile (if drawings at the site are properly scaled)

    Interesting also:
    http://www.alphaglobalex.com/?q=952
     
  13. DaveB
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    DaveB Senior Member

  14. DaveB
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    DaveB Senior Member

    more stuff

    hey,

    Here are some more things you might be interested in (attached)

    -Dave
     

    Attached Files:


  15. catweaselcat
    Joined: Nov 2004
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    catweaselcat Junior Member

    Hey Dave,

    thanks, you found some valuble info for me. Great, good luck with your own projects,

    best regards, Charlie
     
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