Gori Prop Problem

[eyschulman]

Yes prop loss is rare like aircraft crashes. And since it can really ruin your day or worse why not go the extra mile to avoid it-ts real easy to put a little goo on that nut or bolt.

[Boatstuffdc]

Late but not too Late. I offer this prop wise comment. I have had Gori props for about 20 years (basic model) and find that they function as well or better then most). Hit reverse every time. Few can claim that. The Gori's primary weakness is the lack of a shear pin (pins give a nice visual check). To cover for this weakness I doubling up on all of the allen locking screws because all of these type of props have some sort of history, many are know to have come off. I also remove and dismantle every couple of seasons and ran the prop for 10 to 20 hours, including many reverse operations, after an install. Following this break in period I go through the entire install sequence again (minus removing the prop from the shaft) and retighten everything, locking screws included. Never lost one or had one fail. Check it myself with each zinc change. I don't do this with my fixed prop, which I run summer time during extended motoring sessions, because double nutting with a shear pin is nearly fail proof and easy to check from the dock or dingy after any debris hit.
Another wise choice is to carry a fixed backup prop because these folding and adjustable pitch props are simply fancy engineering gadgets that can and will fail if any small vibration or variation in operation occurs. A small vibration, a stick, a log, a hard port turn (depending on your spin direction), heavy seas, metal casting variations, and small variations in the machining of the prop/shaft interface can cause problems for the best props, fixed or not.
Perhaps the cost of all props may be the issue. Research & development, liability, or price gouging. What ever the reason for the cost of these props, fixed or not, seems to defy the logic of current mass production machining technology.
As for a failed pivot pin. I have played with mine, turning them to move the wear to the back side and extend life for a few seasons. I can not imagine one failing without one hell of a hit and/or long term, I mean long term exposure to stress reversals caused by vibrations. They are so over sized and so well supported in the hub that failure seems extremely remote. One would need equipment available in few metal shops to even bend one. In a strike situation I can't believe that the blade would just break off before the pin shears.
Thanks, do regular checks (yourself or a qualified gori man) on life safety equipment and carry a back up.

[China Doll]

I have the Gori 3-blade for a number of years too and find it to be an excellent prop. Would not go back to non overdrive / non folding unless needed to due to a failure and then only on a temp basis. (I carry the original fixed props --both a 2 and 3 blade prop-- as an emergency spare. The 2-blade was the spare for the 3-blade, and now I have two spares.)

I have saved a couple of Gori props from getting ruined. Most yards and owners who have a Gori know little to nothing about the prop. A many have been ruined by lack of maintenance or lack of proper advice on how to remove and service the prop. (One owner with a Cat that had twin engines / drives quoted me with "can't figure out why one engine sometimes runs at lower revs than the other..." Turns out he had no idea that the props could be operated in an overdrive setting --nor did he known the proper procedure. He'd owned the Cat since new and the manufacture never mentioned anything about the "special" props in its litirature.)

The prop of the original post that fall off more than likely did so because the prop was "hot" and was not maintained. It is possible to cook the three locking bolts off the prop which can cause the prop to fall off in reverse.

With that now said, it is possible to do the samething on any prop, folding or fixed.

If you have a Gori or similar folding prop, be sure to find informaiton on the prop and read up to learn how to properly maintain and use the prop. Even if it's a fixed prop, you'd better make sure it is maintained, or you too will be diving for props and dollars in your wallet.

[kibbledog]

I had a Gori prop on my second boat - a CS-27 - worked well - a little less thrust in reverse compared to my fixed, but I learned to compensate for that. I am currently looking for another boat, and will install a folding prop if it doesn't already have one. I can't resist the performance increase of a folding prop - especially close-hauled in light wind.

[SV Demeter]

I have always used MaxProp feathering props with good luck. I have found their customer service worldwide to be excellent. I find close to a full knot of speed increase sailing and spread over 100 or more miles thats a big difference. Yes it requires additional service but I also like the improvement in reverse both in thrust and reduction of propwalk.

The gori is a very interesting prop and one I would definately consider after Nigel Calders article a year or so ago in Sail I think. He discussed the prop and its overdrive feature. Sounded to me like a great way to get the benefits of a variable pitching prop without the complexity.

Is anyone here using a variable pitch prop on their boat now? I know they are used on some very large boats and can result in big improvements in fuel consumption as you can change the pitch once the boat is up to speed and reduce RPMs.

Sure a feathing prop is not as simple as a fixed one but roller furling is complex too and problems with it can take your rig down! Yet I dont see all of us going back to hank on sails. To me the benefits of feathering props far exceed the added risks. Folding props are another story, I have no use for the Martek style two bladed folders. Horrible in gear and rattle around making noise and vibration, yes very low drag but a horrible prop.

As always Your Mileage May Vary...

[senormechanico]

Previous boat had a Maxprop 3 blade (Excellent prop).
On my current boat, I just replaced a folding Gori 2 blade with a Varifold 2 blade folder.
Top speed about the same, but what a difference in midrange!
Gori 4.2 knots, Varifold 5.8 knots at cruise RPM.
Rattle is gone as well.

I'm a believer.

[China Doll]

I failed to mention that not all Gori's are created equally. The 3-bladed prop I have is dual pitched (overdrive), but older 2-bladed props do not have the overdrive ability. Also, think of the overdrive like an overdrive on a car; when motorsailing 'downhill' it is a major engine wear and fuel consumption saver over a non overdrive prop. Motorsailing in less than 3 knots of true wind slightly abaft the beam, with the fixed prop we'd run 2200 rpms to get 8 knots of boat speed with 9 to 10 knots apparent wind, close hauled. With the Gori in overdrive, I can easily idle along at 1200 RPM to make the same 8 knots. (Hull speed is 8.9 knots, typical loading.) Not motorsailing in the same conditions, with the fixed prop, you couldn't stay underway; with the Gori folded flat, you'd still enjoy the sail and make 4 knots over the water. There's a huge difference on our boat between running the engine at 2200 vs. 1200 RPMs, and that is noise. With the Gori in overdrive we have greatly reduced 'noise' on the boat and we have greatly increased our time under sail.

[dennisail]

Gori three-bladed folding propeller test

[Dockhead]

I had a Gori two-blade folding prop fail on a chartered Catamaran some years ago in the Carib. The swivel pin failed and it threw a blade. It did not look well engineered to me.

We have an Autoprop on our current boat and had one on our last boat. Seems better engineered to me, and we've never had a bit of trouble, but these have also been known to throw blades.

The performance advantage over a fixed prop is so huge, both sailing and, in case of the Autoprop which is variable pitch, also motoring (and especially, motor-sailing), that it seems to me worth the extra complexity and risk of failure, and worth the extra maintenance needed. I grease the prop every time the boat is out of the water, so three or four times a year. The Autoprop is simpler than other folding/feathering props with no gears, with the only moving parts being the swiveling blades. Looks fairly robust to me, and it is quite easy to maintain (remove one screw and squirt in grease) and quite easy to evaluate its condition (just grap the blades and feel how the bearings are working).

We do, however, carry a fixed prop as a spare -- just in case.

[fstbttms]

Originally Posted by Dockhead

The Autoprop is simpler than other folding/feathering props with no gears, with the only moving parts being the swiveling blades.

Wow, I completely disagree. The Autoprop has a history of throwing blades (now allegedly remediated) precisely because of the complexity and lack of robustness of the blade assembly.

[Cefernandini]

[QUOTE=gegroves;49106]Please be advised of a problem with Gori Propellers and their US distributor, AB Marine. The propeller can spin off and be lost. We lost ours while maneuvering to anchor in a harbor in Turkey. We notified AB-Marine immediately by email and telephone and left a voice mail message. Since the initial notifications, we have emailed them six times and called three times. They have never responded to any of these messages. After five weeks we were finally able to reach someone at AB Marine.

AB Marine and Gori Propeller have denied that this occurrence is a warranty issue. They claim that the prop can spin off only if it hits something or is installed improperly. I personally installed the propeller six months ago in the US. I know it was properly installed in accordance with the printed instructions provided with the propeller and we did not hit anything with it.

As I understand their position, if the propeller was installed properly then it cannot come off. Ironically, they claim in their brochure “Shaped Blade vs. Flat Blade Comparison” dated January 2005, that the propeller is so easy to install that “there is no chance of a mistake” and “it can be easily installed/removed underwater.” If the propeller is so easy to install that there is no chance of a mistake and then spins off, then logic suggests the reason it came off should not be one of improper installation. They cannot have it both ways.

I know this seems like sour grapes, but when I pay $2800 for a product, I expect to hear back from the company when I write and call repeatedly about a serious problem. Failing to respond to any correspondence for over a month is inexcusable. Be forewarned, if you buy from AB Marine or Gori Propellers and have a warranty or service issue – forget it. They only want your money. They do not care about you once they get gor

Gary
S/Y Vingilot
Lying Marmaris, Turkey[/QU
I lost one three fold 18" x 15 LHS gori prop from my Catamaran two days ago when entering to a buoy in La Punta Yacht Club in Peru. I reallydon't undestand what happen since my boat and prop are only a year new.
Does someone get from GORI a good answer why this happen ? Of course I don't hit anything.
Possible solutions?




OTE]

[svrevelations]

Originally Posted by Cefernandini

I lost one three fold 18" x 15 LHS gori prop from my Catamaran two days ago when entering to a buoy in La Punta Yacht Club in Peru. I reallydon't undestand what happen since my boat and prop are only a year new.
Does someone get from GORI a good answer why this happen ? Of course I don't hit anything.
Possible solutions?

My Gori propeller on my catamaran also fell off for no reason despite a professional installation - I posted about this on another multihull forum. There is only one bolt holding the propeller to the shaft which is then torqued and secured with Loctite. Despite torque and using Loctite, this bolt worked its way loose and fell off. Barring the torqued bolt and Loctite, there is nothing else stopping the bolt getting undone - no split pin, no wire, nor any other mechanical prevention. Upon inspection, the bolt on the other propeller was also loose and this propeller was also about to fall off.

Gori themselves simply repeated the same old rubbish that it was impossible to fall off and was not at all interested in the evidence we offered to show. Based on their blind denial, their lack of interest and unwillingness to look/consider the evidence, I have since switched to FlexoFold props. FlexoFold propellers have multiple bolts thus offering multiple layers of safety against falling off. My one Gori propeller is lying somewhere on the ocean floor and I literally threw the remaining Gori propeller off the boat, which I believe is now decorating somebody's wall at his house. GOOD RIDDANCE!!!

Reverse on the FlexoFold propellers are not as powerful as that of the Gori's - but at least I have propellers on the boat! No use having a powerful reverse which is completely missing due to a propeller which fell off!

[Cefernandini]

Ys I will look for a Flexofold and try to get ridof this GoriProps. The only answer I get from Gori people is that you must have hot something and as you know this is not truth, is just an answer tobet out of the problem.

[Zanshin]

You've revived this 5-year-old thread from a dusty grave!

I had a Gori on my previous boat and was actually quite happy with it. Greasing and inspection and replacing Zincs was all I needed to do and the overdrive functionality was great.

[Cefernandini]

Originally Posted by Zanshin

You've revived this 5-year-old thread from a dusty grave!

I had a Gori on my previous boat and was actually quite happy with it. Greasing and inspection and replacing Zincs was all I needed to do and the overdrive functionality was great.

Can you explain me what are you greasing in your Gori props?