2 blade folding prop stuck open.

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vasant

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Hi all,
After bad performance in a couple of low wind races i started troubleshooting my setup. At some point i noticed that when the engine was not engaged i could hear the prop turning when sailing. This shouldnt actually be happening when the prop is folded so i started thinking the prop might not fold.
So i took a swim to verify and indeed it looks stuck. But somehow really bad to even if applying force on the blades they dont move. Either to unfold further or to fold. Spend more than 30 minutes tryning to clean yp from barnacles or whatever else. Looks hopeless.
Any idea? Prop is Radice i have it now 3rd season.
 
A few photos would help, but must of the folders I know have gears that are open to marine growth. Have you got all the barnacles out of the way of the mechanism? Wouldn't take much to stop it closing automatically.
 
Those are fresh pics. Not sure if they help. Yes i cleaned the gears with a screwdriver but when i say the prop is stuck i mean stuck. Normally a barnacle wil be squashed if you operate the folding mechanism by hand....
 
It is not just barnacles or other large marine growth that cause problems in free operation. It could well be calcareous deposits on the pins on which the blades pivot.
 
Hi, that looks very much like the Volvo folding prop on my saildrive. I was going to say dry out, but I see that you are out in Greece. If you have your boat lifted, you will find that inside the small holes on the front of the hub there are two Allen key grub screws. Release the these locking screws and with a small flat punch you can tap out the stainless steel pins holding the prop blades. You can then clean them up. I grease them with a waterproof grease before reassembly. I need to take off the prop to change the saildrive anode so this gets done at the start of the season with the antifouling.
 
PuffTheMagicDragon said:
It is not just barnacles or other large marine growth that cause problems in free operation. It could well be calcareous deposits on the pins on which the blades pivot.
Click to expand...

Thanks. I would never think of that it could be that affecting. But still i need to point out its ROCK solid. So catching both blades and pushing back and forth has zero effect. Anyway... probably i will have to wait for haul out
 
Although the teeth look in reasonable condition from the photos, that make of prop is prone to dezincification and it is quite possible that the inner teeth that are holding the blades open are broken and jammed.
 
I have the same propeller. It won't take much to stop it closing because the gearing means that any resistance in either blade affects the other one. There may be growth behind the gears inside the hub. I get quite a lot of calcified growth in there each season. Have you scraped clear the areas at the sides of the base of the blades - the small triangular areas in your photos?

It might be worth just tapping the ends of the blades to see if you can get them moving.

As an aside, those hexagonal grub screws are a pain. The hexagonal part is an insert in the screw and very prone to letting go and disintegrating making it almost impossible to remove the screws. I replaced mine with some modified machine screws. I ground the ends to a point, chopped off the heads and cut a deep slot for a flat bladed screwdriver.

Incidentally, my propeller must be 20 years old so yours is relatively new!
 
Thanks dipper.
I hope you are right and its not somethiing more substantial. I tried indeed to clean up also behind the gear inside the hub, but not sure if there was something and to which extend i could clean it. In the end, there are also physical limitations i.e. end of October water isnt that warm anymore and also staying underwater is limited if you dont have the proper gear and rely on your breath.

I tried tapping the gear and the blades but admitedly not heavily...

The hex screws i changed this year. usually i put some silicone on it which i remove at teh end of the season , hoping that this will protect it a bit....
Thanks
 
Hi all.
Thanks for your interest and your suggestions.
Finally after haul out it was revealed that the safety screw on the shaft became loose blocking the wings from closing.
so take care on these and maybe next time I will use some thread locker
 
Thanks for the update. I am sure that it will prove useful to others with folding prop problems.
I do wish that more people would do the same as you have. :encouragement:
 
vasant said:
Hi all.
Thanks for your interest and your suggestions.
Finally after haul out it was revealed that the safety screw on the shaft became loose blocking the wings from closing.
so take care on these and maybe next time I will use some thread locker
Click to expand...

Many Loctites are anaerobic and will set off underwater. I would not use the type that requires heat to release but some (many) of the others are fine.
 
Re folding props with meshing cogs ( I had one of these on a Volvo saildrive and it worked fine, apart from an acceptable loss of motoring performance - but that was in tidal waters with regular dry / haul outs ) - I once met an owner of a Carter 33, Greek built funnily enough, which had a folding prop with independent, non meshing blades; he reckoned it was a disaster, very often only one blade would flick out, resulting in huge vibration and very little drive.
 
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