Re: [Amel Yacht Owners] Furling Gearbox Differences

Craig Briggs

Hi James,
Interestingly, these reduction gears are sold as "permanently lubricated" with gear oil (close, but not generic SAE 90 - you can google the specific oil). HOWEVER, the expected applications for which they are engineered are "friendly" industrial environments, typically in interior machine rooms with the orientation of the reduction gear being vertical (the oil flows nicely over the gears) and it gets thousands of hours of virtually continuous operation and never needs lubrication.  NOT ON AN AMEL.

Our application could not be more different: it requires disassembly of the factory sealed unit (so long "permanently lubricated") to add the plastic spacers and re-drilling the mounts, plus a horizontal orientation (so oil will pool on one side) and, of course, the environment is hostile and the usage is infrequent (compared with industrial applications) with long periods of baking in the sun at high temperatures. The conditions for "permanent lubrication" have been totally voided and no longer exist. 

Now, what  Amel did is to break the factory seals to modify it for the black delrin shims and replace the factory supplied oil with grease. Owners have improved on the Captain's engineering (I can see Bill R getting excited!) by adding grease fittings so they can do preventive maintenance and keep the grease topped up. 

As for tapping the grease fitting holes, there is enough clearance inside such that you can drill and tap a hole anywhere - do be careful, of course. Better yet, since you have to open the replacement unit to add the shims, just pop off the side plate and get a visual on where to drill and tap. Watch out for getting metal chips inside.

As for grease getting thrown off the gears as they spin, remember that our application is so infrequent as compared with a continuous industrial application that it is inconsequential - keeping the housing full of grease will provide more than adequate lubrication, (which, actually, is hardly needed). More to the point, the grease is there not so much for lubrication, but to keep the housing full and prevent any water ingress, which is the culprit in corroded bearings that allow the worm gear to wobble and destroy the gear train.

So go drill and tap and it will be fine.

Cheers, Craig Briggs SN#68

---In amelyachtowners@..., <jean.boucharlat@...> wrote :



There are entire libraries filled with heavy books, theses, knowledgeable opinions, about the respective merits of grease and oil.

You can spend the upcoming winter making up your mind if you have the courage to investigate thoroughly this particular issue.

Take the plunge, make your own decision about what fits your particular circumstances.


Jean Boucharlat

Formerly SM 232


From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: vendredi 10 novembre 2017 05:29
To: amelyachtowners@...
Subject: Re: [Amel Yacht Owners] Furling Gearbox Differences



What is the consensus of others, then, regarding using gear oil versus grease for the furlor and outhaul gearboxes?

Indeed, it would seem that gear oil would be the appropriate lubrication, but I look to those smarter than me… 



On Nov 9, 2017, at 10:47 PM, divanz620@... [amelyachtowners] <amelyachtowners@...> wrote:


If you are going to disassemble the gearbox, why not just fill it with SAE90 oil?

That will do a much better job of keeping the gears lubricated than grease.

Grease tends to get thrown off gears as they turn and doesn't stay where the gears are meshed, which is what you really want to lubricate.



Elyse SM437

On the hard, raising the waterline



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