What bearings for anchor roller?

[GHA]

I'm not sure if my roller turned with the snubber, since it is something I very seldom did (bridle). I agree with others that a fully threaded rod seems very strange in this application. I was working on mine last week, and it is a smooth bolt with some play at the ends. The roller turns under very light pressure and at high load.

Despite the forum armchair tut tutting back in the real world there is actually very little wear from the rollers running on a threaded bolt shank, much less than I thought which was part of the driver for all this. You can feel the pattern of the thread in the inside of the acetal but still very little play. After what must be about 15 years mostly on the hook since they were fitted. Though they don't actually move much, chain is usually pretty slack getting raised & the onboard snubber is a new addition about a year ago. Quite deep chain link shaped wear on the outside of the chain roller, not a slot any more.

Probably would be fine for another decade, but not right so it will get changed.

The vast majority of the movement comes from onshore winds & a steep chop with the bow pitching up and down a good few feet, the snubber is constantly extending/retracting then sometimes for days. That's a lot of rotation under quite a bit of load.

Up to 35Kts (I've not spent time watching in anything higher) the load is close to constant, boat will tack but it's a gentle affair changing tack, the snubber might extend a fraction as the wind catches the beam afterwards the the stories of boats shooting across anchorages in a stiff wind don't happen on this boat.

 

[Neeves]

the snubber might extend a fraction as the wind catches the beam afterwards the the stories of boats shooting across anchorages in a stiff wind don't happen on this boat.

I think, as you suggest, they are just stories.

Commonly the extension of the snubber is 'similar' to the straightening of the catenary in an all chain rode - you don't hear stories of yachts shooting across anchorages as the catenary straightens and then returns to its normal state of sag.

Jonathan

 

[NormanS]

Despite the forum armchair tut tutting back in the real world there is actually very little wear from the rollers running on a threaded bolt shank, much less than I thought which was part of the driver for all this. You can feel the pattern of the thread in the inside of the acetal but still very little play. After what must be about 15 years mostly on the hook since they were fitted. Though they don't actually move much, chain is usually pretty slack getting raised & the onboard snubber is a new addition about a year ago. Quite deep chain link shaped wear on the outside of the chain roller, not a slot any more.

Probably would be fine for another decade, but not right so it will get changed.

The vast majority of the movement comes from onshore winds & a steep chop with the bow pitching up and down a good few feet, the snubber is constantly extending/retracting then sometimes for days. That's a lot of rotation under quite a bit of load.

Up to 35Kts (I've not spent time watching in anything higher) the load is close to constant, boat will tack but it's a gentle affair changing tack, the snubber might extend a fraction as the wind catches the beam afterwards the the stories of boats shooting across anchorages in a stiff wind don't happen on this boat.

So if there's very little wear, what are you fussing about?
Tut tut.

 

[GHA]

So is all acetal the same in not expanding in seawater? Like these >>

75mm Round Delrin Acetal black plastic bar ends | eBay

tia

 

[Aja]

So is all acetal the same in not expanding in seawater? Like these >>

75mm Round Delrin Acetal black plastic bar ends | eBay
View attachment 179455
tia

Yes. Delrin is the trade name.

 

[vyv_cox]

So is all acetal the same in not expanding in seawater? Like these >>

75mm Round Delrin Acetal black plastic bar ends | eBay
View attachment 179455
tia

Yes I believe so. Delrin is DuPont's trade name for it. My replacement rudder bearings are acetal, no idea of source, no expansion after many years in service.

 

[GHA]

Yes. Delrin is the trade name.

Yes I believe so. Delrin is DuPont's trade name for it. My replacement rudder bearings are acetal, no idea of source, no expansion after many years in service.

Thanks. Cruiser Spidey sense tingling very loud looking at that ebay listing, - "at some unknown time in the future in some unknown way in some unknown anchorage...some acetol offcuts will come in very useful.."