Plastic Bow Thruster Props

Posted by Andreas1120@reddit | sailing | View on Reddit | 16 comments

Hello All

I am doing a refit on my aluminum yacht, and I have a new bow thruster.

The yard is supplying PLASTIC bow thruster props. (With ample spares)

When I objected to this, the project manager pointed out that mixing metals is not desirable.

So bronze props is not a good idea.

In general, this is true.

Do you agree?

They also make aluminum props, should I ask for one of those?

thank you for all advice

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hew3@reddit

What brand thruster? I’ve been running a Sleipner for 5 years with plastic props and it works fine. Most important thing is to keep it free of hard growth.

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Andreas1120@reddit (OP)

Funny I think mine is a sleipner. Out of Norway right?

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daysailor70@reddit

Former boatyard owner, I never serviced a thruster that didn't have a plastic prop. I know one thing, I'd rather have a plastic prop then a metal one if I sucked in a piece of line.

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Plastic_Table_8232@reddit

Agree. Rather replace a prop than the tail piece.

Prop is easy to change in the water and relatively inexpensive.

Removing the tail piece means hauling out or drying out. So add a few hundred for the haul on top of $700 for the tail piece. They are never in a spot that’s easy to access or work in either.

IMHO - The best way to keep a bow thruster in a good condition is to keep the compartment it is in leak free. Also - know the duty cycle and don’t exceed it.

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foilrider@reddit

I don't know, the whole rest of the boat is probably plastic, right?

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Tikka2023@reddit

Normally they have nylon bolts too so the bolts sheer in the event of an entanglement and you only lose the prop and don’t damage the motor.

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whyrumalwaysgone@reddit

Plastic props are pretty normal here. Mixing metals isn't a huge deal, since it has a prop zinc right there usually. I would just go with it

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millijuna@reddit

While colloquially called “plastic” the reality is that it’s a composite material, probably a mix of nylon, fiberglass, epoxy and other materials.

If it’s good enough for mission critical applications like airplane propellers, it will be fine for your little bow thruster.

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On Vetus bow thrusters plastic props are standard. I am 15 years into mine on our 48 foot monohull without any issues. I don't see a problem with plastic. They are easier to get growth off of as well.

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TheAmicableSnowman@reddit

Another thought: although there is probably a sheer pin...

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Andreas1120@reddit (OP)

Or the prop is the part designed to fail.

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Icy_Respect_9077@reddit

What's the manufacturer's recommendation? It's not out of line to have a plastic prop on a small hp motor. For example I have a 2 hp Honda kicker for my dinghy that has a plastic prop.

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Andreas1120@reddit (OP)

I may just be having an emotional reaction against the notion of plastic.