Gori prop internal fouling

[Pine Painter]

Wondered if anybody else has had problems removing the hub of a 3 blade Gori folding prop due to accretion of calcite inside the screw cap.
We are cruising in tropics and have removed prop for first time since new (after 20 months). It was very hard to get the front cap to unscrew, sea water gets into the cap and in high fouling waters (SE Asia) calcite deposits build up very fast. Has anybody else encountered this and how did you resolve the issue. I have ideas based on experience thus far and wanted to hear from anyone who might be a stage ahead of where we are with this issue.

[nhschneider]

I installed a 3-blade Gori prop in 2009 and took it off for the first time last month. It was not an easy removal.

To make a long, hard story short, what finally worked was an acetylene torch with an MFA (Multi Flame Acetylene) tip (also called a 'rosebud'), probably a #12 but it might have been a #15. The cone (Gori calls it a 'jacket') was heated but the high concentration of heat allowed the jacket to heat more quickly than the hub and using massive pipe wrenches, (two large Trinidadians on the wrenches and a third manning the torch) we were able to get the jacket off (I broke the spanner wrench that came with the prop). This has been the only problem I've had with our Gori prop and that's after more than 35,000 miles of cruising. It's now scarred from the teeth of the pipe wrenches but I'm not hesitating to reinstall it.

Fair winds and calm seas.

[Pine Painter]

We spent a week doing a cycle of applying hydrochloric (muriatic) acid with hypodermic, washing with water, then acetone, then releasing oil, then heating. With each cycle we could move it a fraction more until it opened enough to get more acid in to dissolve calcite. The tolerances around jacket at front are so tight it was seized with calcium carbonate. We think we are going to tap a hole through jacket into which we can screw a grease nipple to keep inside pumped full of grease. That tapped hole can be blocked with a grub screw.
We had a couple of emails with Gori in Denmark, but they don't seem interested in ideas to improve their product. We like the dual pitch aspect and overall find the Gori prop an improvement on our previous Maxprop, apart from this issue of seizing up which hinders removal. What are your thoughts on reassembly with a view to making it easier to take apart next time? Oh yes, we needed to repair the supplied C-Spanner twice, and use long torque levers to make progress, bronze hole got distorted.

[fstbttms]

Maybe having the prop cleaned once in a while might prevent this from happening. Just sayin'.

[AD28]

Gotta agree with FB...

and am also wondering whether the chems and heat are possibly compromising the internal dampener bits

Maybe AB Marine can offer some advice? HOME - AB Marine

[LByers]

I experienced this problem in El Salvador four years ago when my blades seized up in 2/3 forward position. After removing the prop in the water, (that was quite an adventure), I injected vinegar into the gears with with a syringe and kept working at it until it loosened up. If you're on the hard, the same process may work for you.

Cheers

[nauticalnomad]

I had a Gori prop that was 3 years old (apparantly) when i bought the boat.
I was coming into the berth forward and then put the boat astern to hear a clunk then nothing.. Had to jump off and save the boat from ramming the pontoon.

I dived in and had a look under the water and there was a clump of black rubber on the shaft and i couldnt find the rest.

I contacted Gori and they told me they have not heard of it happening but to do my a favour they would sell me one for cost price..

I have spoke to a few marine engineers and its a common thing with Gori props..

It had sheared off from the vulcanised rubber insert inbetween the inner and outer part of the folding prop..
Not sure what had happened though to cause it.. It could of been putting heat on the prop to take it off etc..?

[Pine Painter]

There is no vulcanised rubber in our prop design? As for cleaning suggestion. We clean every 3 weeks or so when in tropical waters to keep exposed gears clear of calcite build up. The problem is internal to the nose jacket. Removing that involves taking off the prop assembly to rear. Not something we want to do afloat unless we absolutely have to. Unless people have experienced the rate of calcite growth found in some tropical warm water regions it is hard to imagine. In some locations your chain and prop will foul with thick cacite growth within 2-3 weeks. We never saw anything like it in European waters, even the East Caribbean was relatively benign by comparison.

[nauticalnomad]

It must only be the saildrive options..
It states it on this link..
gori_propeller_spare_parts

[Pine Painter]

Ah, OK, we don't have sail drive so no vulcanisation. Thanks for that clarification.

[quandary]

I've taken my Gori apart completely on the hard without too much difficulty once I worked out how all the lock studs came out.
The build up of fouling in the gears etc is a worry, especially if the boat is moored and unused for long periods. I think one needs to exercise the prop quite regularly by engaging forward/astern and getting the revs as high as possible to dislodge/crush fouling as much as possible.
I wondered if covering/sealing the prop with a black plastic bag and elastic band around the propshaft might inhibit the growth if the boat is left in the water for long periods. (bit of a pain to dive and fit/remove but probably less hassle than having to haul out and strip the prop?)

[Pine Painter]

We have used a heavy black plastic bag around the prop when leaving the boat in a marina while travelling for a period. It does reduce fouling. We don't do it when anchored, even for a couple of weeks in one location, in case we have to get under way in an emergency situation.

[SilentOption]

I'm contemplating a 4 blade Max Prop but I see some comments here that concern me.
Can anyone here who has owned a Max Prop elaborate on issues they've had.


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