Propeler ice protection

Discussion in 'Sailboats' started by polarka, Nov 6, 2008.

  1. polarka
    Joined: Nov 2008
    Posts: 3
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: New Zeland

    polarka New Member

    I am looking for any ideas how to protect my propeler from floating ice in Antarctic water. Anybody can help me please. I do not need anything fancy, just a frame. A picture woould help a lot. Thank you
     
  2. Fanie
    Joined: Oct 2007
    Posts: 4,603
    Likes: 174, Points: 63, Legacy Rep: 2484
    Location: Colonial "Sick Africa"

    Fanie Fanie

    Maybe something like this in front of the prop ? Just an idea.
     

    Attached Files:

    • Ice.jpg
      Ice.jpg
      File size:
      36.3 KB
      Views:
      377
    • Ice1.jpg
      Ice1.jpg
      File size:
      57.3 KB
      Views:
      359
  3. polarka
    Joined: Nov 2008
    Posts: 3
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: New Zeland

    polarka New Member

    thanks

    I made a frame around the prop so far and this will help, I will use it, somehow. Thanks
     
  4. Kay9
    Joined: Oct 2006
    Posts: 589
    Likes: 26, Points: 0, Legacy Rep: 279
    Location: Central Coast Oregon US.

    Kay9 1600T Master

    My thought would be, if the ice is deep enough to get to your prop you probably have bigger issues.

    6" of ice is like hitting a solid rock, and will most likely put a hole in your hull.

    However in the CG on the smaller hulled vessels, we have used simple shrouds. Allthough about 1/2 the time the shourd bends and causes more problems then simply hitting the ice.

    K9
     
  5. polarka
    Joined: Nov 2008
    Posts: 3
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: New Zeland

    polarka New Member

    ice thicknes

    Thank you,

    my worries came from floating pieces when I have to motor through them. The sucction of the propeler.

    I am not planning to break any ice.

    I know that Dawid Lewis on Icebird had a protected propeler on his Antarcitc solo voyage.

    I made something yesterdat, I call it Polar Spider, it looks like a spider net but it is very solid. Stronger than the boat...

    It will slow me down to cross Pacific but I hope it will make a good job in the south.

    Daniel
     
  6. Stumble
    Joined: Oct 2008
    Posts: 1,909
    Likes: 71, Points: 48, Legacy Rep: 739
    Location: New Orleans

    Stumble Senior Member

    Is there anyway you could make the web removable for times you are not planning on being in artic conditions? It seems that inducing that amount of drag while necessary would become old very quickly when not in the ice.
     
  7. Brent Swain
    Joined: Mar 2002
    Posts: 951
    Likes: 35, Points: 0, Legacy Rep: -12
    Location: British Columbia

    Brent Swain Member

    I once bashed thru 1/4 mile of five inch ice in three days . Didn't hurt the prop a bit. Dont worry about it.
    Brent
     
  8. marshmat
    Joined: Apr 2005
    Posts: 4,127
    Likes: 149, Points: 63, Legacy Rep: 2043
    Location: Ontario

    marshmat Senior Member

    Our local ferry is (I think) around 1000 tonnes, and has four azipod drives.

    There is a bubbler line between here and the island to keep her path reasonably clear, but a lot of ice chunks still drift in. Chunks, often big ones, do get sucked down into the props. I think this is the kind of scenario you're talking about, polarka, as opposed to breaking through solid ice?

    The boat I just mentioned has, I believe, fairly conventional bronze props, and operates year-round, 5 months of it in these conditions. I've taken perhaps fifty trips on her when the ice was 6" thick or more and drifting around in 10-foot-plus sheets. You'd feel a slight shudder when a prop munched one of these into 5,000 icecubes, but not once have I noticed a vibration that even vaguely resembled prop damage. I don't think her captain even notices anymore.

    I think if you have a beefy, oversized shaft and beefy, oversized bearings, swinging a good solid prop at a reasonably low RPM, ice shouldn't pose too big a threat to the propeller until you get to the point where it's threatening the rest of the boat also.
     
  9. TeddyDiver
    Joined: Dec 2007
    Posts: 2,588
    Likes: 125, Points: 73, Legacy Rep: 1650
    Location: Finland/Norway

    TeddyDiver Gollywobbler

    Matt is right.. Never tried to push down in the water any piece of ice? It's just as hard as trying to sink a buoyo with an oar..
     

  10. chowdan
    Joined: Jul 2008
    Posts: 91
    Likes: 2, Points: 8, Legacy Rep: 10
    Location: Seattle WA

    chowdan 1980 PAC41 Liveaboard

    I just had a thought that might be a good idea. Maybe not but here it goes.

    If you take a design like the on Fanie came up with, and changed it so that it wont always be down and cause so much drag to slwo you down, but have it so it can fold up. This way when you are sailing the warmer water it wont be needed. Maybe have a hydraulic-ram that pushes and holds it down.

    The salt water wouldn't be so good for the ram but it's a start on smoething a little more effective.
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.