Ice class/Icebreaker hullshapes?

[catweaselcat]

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

[Robert Gainer]

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

[kach22i]

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

[safewalrus]

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!

[Wellydeckhand]

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

[kach22i]

Originally Posted by Wellydeckhand

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

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?

[Gilbert]

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

[Wellydeckhand]

[quote=kach22i]Don't worry, we won't tell anyone of your fetish.

I get all this cheap shot at sex comment and joke online.....ye............ I am almost a real life Tarzan with a laptop......... Fujitsu thanks............ with girls exodus from their jungle just wanna touch my wireless mouse...... ......... My only fetish is kach22i in bikini LOL

[catweaselcat]

@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

[Wellydeckhand]

I apologies if any taken offend........ it was off the thread and not mean for u................

[kach22i]

Originally Posted by Wellydeckhand

I apologies if any taken offend........ it was off the thread and not mean for u................

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.

[Guillermo]

Originally Posted by Robert Gainer

Small boats don’t make good icebreakers.... A small boat does not have enough inertia to keep moving in ice....

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

[DaveB]

just found a good document with lines:

http://www.skibstekniskselskab.dk/do...5_ice_HSVA.pdf

[DaveB]

hey,

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

-Dave

[catweaselcat]

Hey Dave,

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

best regards, Charlie