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Old 29-09-2020, 08:15   #1
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One arm of folding prop missing - do I need to take out the boat to fix it?

May be a silly question, but here it is:

I have lost one arm of 4 of a folding propeller. Don't ask me how. Just fell off whilst I was reversing at anchor.

Now, can this be fixed whilst the boat is still in the water, or do I need to haul it out onto the hard?

With one arm missing there is a lot of asymmetry in the system and the engine is vibrating like mad when I am doing only 800 RPM. So, I cannot manoeuvre well when I am in the harbour and it looks all pretty scary to me.

Thanks a bunch for any advice!

Mathias

PS: And how can this happen? Without external impact? Is there a maintenance procedure one has to follow? The boat is new, 1.5 years, and has been all that time in the water...
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Old 29-09-2020, 08:24   #2
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Re: One arm of folding prop missing - do I need to take out the boat to fix it?

You'll either need to hire a diver to go down and remove the prop or haul it and have it removed. If you haul it, I would do so when I have a replacement in hand. Otherwise you might get charged at a daily rate for storing in the yard waiting for the prop to be repaired of for one to be sourced, shipped, delivered and installed.
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Old 29-09-2020, 08:29   #3
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Re: One arm of folding prop missing - do I need to take out the boat to fix it?

What brand?
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Old 29-09-2020, 08:55   #4
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Re: One arm of folding prop missing - do I need to take out the boat to fix it?

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Originally Posted by Shrew View Post
You'll either need to hire a diver to go down and remove the prop or haul it and have it removed. If you haul it, I would do so when I have a replacement in hand. Otherwise you might get charged at a daily rate for storing in the yard waiting for the prop to be repaired of for one to be sourced, shipped, delivered and installed.
Thanks! Diver looks like an appealing option. My berth is 8.9 metres and so far I have not been able to locate a marina that can haul me out of the water...

And yes, I need all the stuff here before I start the procedure.
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Old 29-09-2020, 08:56   #5
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Re: One arm of folding prop missing - do I need to take out the boat to fix it?

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Originally Posted by Cheechako View Post
What brand?
I have asked the shipyard what brand the prop is. I have to admit I do not know.
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Old 29-09-2020, 08:58   #6
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Re: One arm of folding prop missing - do I need to take out the boat to fix it?

Check if you will need a key for the shaft.
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Old 29-09-2020, 09:05   #7
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Re: One arm of folding prop missing - do I need to take out the boat to fix it?

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Check if you will need a key for the shaft.
Thanks. What do you mean with 'key'?
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Old 29-09-2020, 09:07   #8
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Re: One arm of folding prop missing - do I need to take out the boat to fix it?

Knowing the brand will probably determine what you have to do. Some it is possible to repair in the water or pull the prop, repair and put it back on.

If you cannot find the brand can you free dive down with a GoPro or other waterproof camera and take a picture?
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Old 29-09-2020, 09:09   #9
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Re: One arm of folding prop missing - do I need to take out the boat to fix it?

How long can you hold your breath?

If you use the engine, you risk doing damage to your prop shaft, bearings, and supports as the prop is badly out of balance. This could get very expensive.

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Old 29-09-2020, 09:14   #10
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Re: One arm of folding prop missing - do I need to take out the boat to fix it?

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How long can you hold your breath?

If you use the engine, you risk doing damage to your prop shaft, bearings, and supports as the prop is badly out of balance. This could get very expensive.

Yes, this is why I really do not want to attempt using it to go enter a marina and the location of a lift...
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Old 29-09-2020, 09:15   #11
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Re: One arm of folding prop missing - do I need to take out the boat to fix it?

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Originally Posted by skipmac View Post
Knowing the brand will probably determine what you have to do. Some it is possible to repair in the water or pull the prop, repair and put it back on.

If you cannot find the brand can you free dive down with a GoPro or other waterproof camera and take a picture?
It is a Volvo engine and apparently it all came in one bundle from Volvo. I am waiting for the ship yard to come back with more details...
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Old 29-09-2020, 09:19   #12
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Re: One arm of folding prop missing - do I need to take out the boat to fix it?

The Flexofold 4-blade folder has 4 separate hinge pins for the blades. I suspect this is true of most 4-blade folders (some 2-blade have a single hinge pin). The hinge pin is held in place with a locking screw that is in turn held in place with Loctite. So...

The hinge pin can wear out (not likely unless a lot of hours or faulty); the hinge pin can corrode (how is the electrical system on the boat/at the marina?); the locking screw can back out (not enough Loctite, poorly applied, etc.) and then the hinge pin just falls out (or is thrown out when placed in gear). All of these, on the Flexofold at least, can be repaired in the water, however depending on the root cause you may want to sort things out in a more detailed way.

First thing I would do is jump in (or get a diver) to take a look and see what is there. If the hinge is missing then probably just getting parts and replacing. Another option is gross failure of the hub, which then becomes more of a question.

[Edit] Posted at the same time. If this is a Volvo 4-blade you can see the exploded drawings in the Installation Manual. Looks like a locking screw with Loctite, similar to Flexofold:
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Apply thread lock to the lock bolts (7). Screw in and tighten the lock bolts (7) with a 6 mm Allen key. Tightening torque: 10 Nm (7 lb.ft.).
[/Edit]
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Old 29-09-2020, 09:29   #13
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Re: One arm of folding prop missing - do I need to take out the boat to fix it?

Quote:
Originally Posted by Dsanduril View Post
The Flexofold 4-blade folder has 4 separate hinge pins for the blades. I suspect this is true of most 4-blade folders (some 2-blade have a single hinge pin). The hinge pin is held in place with a locking screw that is in turn held in place with Loctite. So...

The hinge pin can wear out (not likely unless a lot of hours or faulty); the hinge pin can corrode (how is the electrical system on the boat/at the marina?); the locking screw can back out (not enough Loctite, poorly applied, etc.) and then the hinge pin just falls out (or is thrown out when placed in gear). All of these, on the Flexofold at least, can be repaired in the water, however depending on the root cause you may want to sort things out in a more detailed way.

First thing I would do is jump in (or get a diver) to take a look and see what is there. If the hinge is missing then probably just getting parts and replacing. Another option is gross failure of the hub, which then becomes more of a question.

[Edit] Posted at the same time. If this is a Volvo 4-blade you can see the exploded drawings in the Installation Manual. [/Edit]
Thanks a lot for all this most useful information! I hope to get the required information from the shipyard any time soon.

When I dove down there, it seemed that one entire blade is missing, so right from the point where it hinges for folding / unfolding.

My preference would be to get this repaired in water so that at least I can manoeuvre again. If needed, I can then see to get the boat hauled out, but for now it seems difficult in Panama on the Pacific side... 8.9 metre berth is thinning out my options quite severely...
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Old 29-09-2020, 09:31   #14
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Re: One arm of folding prop missing - do I need to take out the boat to fix it?

Quote:
Originally Posted by MathiasW View Post
I have asked the shipyard what brand the prop is. I have to admit I do not know.
I believe it's a Volvo folding saildrive propeller. But you will need to know the size to order parts.
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Old 29-09-2020, 09:31   #15
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Re: One arm of folding prop missing - do I need to take out the boat to fix it?

Sounds like a perfect job for Hookah. Is the water clean and clear? Might want to check the other pins. Maybe someone forgot the loctite.

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