Propeler ice protection

[polarka]

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

[Fanie]

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

[polarka]

I made a frame around the prop so far and this will help, I will use it, somehow. Thanks

[Kay9]

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

[polarka]

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

[Stumble]

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.

[Brent Swain]

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

[marshmat]

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.

[TeddyDiver]

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..

[chowdan]

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.