What bearings for anchor roller?

[GHA]

Both my bow rollers were turned from acetal. Not sure how long ago, ten years? No obvious wear. Acetal is a widely used self lubricating polymer that is just about ideal for the job. Nylon swells considerably in water, up to 11% for some grades.

I did know about nylon swelling but forgot it was so much.

The mists clear a little....

It's coming back to me now, I bought some acetal off a cruiser in Brasil ages ago & had a local fabrication shop sort out a better bolt & turn down the roller. Then it didn't get touched til the on deck snubber was fitted about a year ago.

So it is acetal. Another option - the axel is a M20 bolt fully threaded which is starting to wear the roller, 1" stainless seamless tube should fit over that pretty tight then get the hole in the roller reamed out so it's a slightly sloppy fit on the stainless. Also means I can crank up the bolt onto the cheek plates & tube, at the moment even though they're 6mm plate, crank the nut too much will bend themin a bit & jam the roller. Off to Faro tomorrow where there's a very big stainless stockist, he'll likely have some, maybe even in metric if such a thing exists.

The whole point of this was to get hold of any materials needed with the rare luxury of an address soon

And the spare acetol can be turned into sheaves to fit on deck for the snubber diversions at some point . It's slowly coming together, with very little involvement of the wallet

thnx all.

 

[GHA]

Starboard roller for chain is bronze. Snubber is nylon rode passing through a piece of pvc hose over an acetal roller. This has a small worn area maybe to a depth of 2mm but roller so cheap I had a spare made at the same time. Maybe overthinking things?

Admittedly I'm not at anchor every night for days on end, but works for me

Bit different as it's not so much days as always! The boat is either on passage or anchored.

Plus there's a psychological element which never really gets discussed, the anchoring system is way up near the top of the list of most important bits of the boat, with a bit of time thinking and a little cash the snubber roller can be better, bit closer to absolutely rock solid bullet proof than it is now.

And it should, then with the boat getting flung around for a few days in a blow in the anchorage when you tucked up with some jazz on and a kindle, when your mind (as it does) wanders from one end of the anchoring system to the other you'll know the roller is unlikely to be the cause of any problems, you've done your bit and can relax a tiny bit more, at least with that element.

Even with slippy dyneema if that roller jams it will cut through it in no time then there would be a huge bang! Only ever snapped one snubber (chafe & stupidity) , thought I'd been tee boned by a jet ski going flat out! First reaction was "wtf is a jet ski doing out in this!!! "

 

[Beneteau381]

Posh git!

I've a short length of 12mm dyneema going over the spare bow roller (just cos there was a bit in a locker as much as anything) soft shackled into the chain so it can chafe away to next to nothing & still hold. not that it should but the real world can bite yer bum sometimes at 3am when it's blowing up.

Vague head CAD drawings of mounting sheaves semi permanently on deck for the nylon snubber instead of pulley blocks so a length of bearing material may well come in handy. And a little dusty back street machine shop one day to turn it all up for cost of an airport coffee or 2

Ive got a lump of round stuff, came off a dinghy, used as a roller, 6” by about 4” if I can find it. C will look tomozin the garage, out ther in August if I’ve got it.

 

[Neeves]

If you use a bridle you can do 'something' like this:


Run from the transom to the bow (It will be almost a straight line - no friction nor abrasion), using blocks on the stanchions and a block, or 2, on the bow





For a single snubber instead of a ball bearing in the bow roller simply attach a cheek block to the 'outside' of the cheeks of the bow roller. With some imagination the stanchion blocks can be replaced with soft shackles + LFR and with a bit more imagination you could 'hang' a LFR off 'something' on the bow - depends on what structure you have at the bow.

Jonathan

 

[Porthandbuoy]

I have a double bow roller. The starboard one is bronze and a rattling fit over a stainless shaft. The port one is some sort of tough plastic and is a nice sliding fit on its stainless shaft.
Anchor chain goes over the starboard side as that is aligned with the gypsy.
Snubber, a length of climbing rope, over the port side with the chain hook just kissing the water and made off to an aft cleat. A snatchblock on a midship cleat ensures a fair lead.

 

[Roberto]

Another option (actually I think the best chafe guard for everything that moves).
Two firemen hose, a large one (brown) and a smaller, stiffer one (red). The rope to be protected is tied to the red, internal hose, they move together. The brown hose sits over the roller and it is tied to it (or fairleads or whatever), it does not move WRT the boat.
As the snubber (or think JS drogue bridle) elongates, the red hose moves inside the brown one: there is no friction between rope and anything else, no friction against the roller either, it's all concentrated bewteen the two hoses. They are basically indestructible, the brown one has an inside aramid fabric, one needs a drill to make a hole in it, likewise the red one, which also takes a lot of effort to be bent. A lot better than simply stuffing the rope in a plastic water hose.
It's also rewarding to look at the whole thing while it is working

 

[GHA]

Another option (actually I think the best chafe guard for everything that moves).
Two firemen hose, a large one (brown) and a smaller, stiffer one (red). The rope to be protected is tied to the red, internal hose, they move together. The brown hose sits over the roller and it is tied to it (or fairleads or whatever), it does not move WRT the boat.
As the snubber (or think JS drogue bridle) elongates, the red hose moves inside the brown one: there is no friction between rope and anything else, no friction against the roller either, it's all concentrated bewteen the two hoses. They are basically indestructible, the brown one has an inside aramid fabric, one needs a drill to make a hole in it, likewise the red one, which also takes a lot of effort to be bent. A lot better than simply stuffing the rope in a plastic water hose.
It's also rewarding to look at the whole thing while it is working
View attachment 179323

Nice, handy to know. Though coming from a theatre rigging background instinct goes towards chafe being impossible so the system can run 8 shows a week for years with no wear Plus there's a bit a 12mm dyneema over the roller. but now I want some cast off firemans hose! Will be used somewhere

 

[Neeves]

I have a double bow roller. The starboard one is bronze and a rattling fit over a stainless shaft. The port one is some sort of tough plastic and is a nice sliding fit on its stainless shaft.
Anchor chain goes over the starboard side as that is aligned with the gypsy.
Snubber, a length of climbing rope, over the port side with the chain hook just kissing the water and made off to an aft cleat. A snatchblock on a midship cleat ensures a fair lead.

If you route from the hook, to your starboard section of the bow roller then to a snatchblock on the midships cleat, to a turning block aft, say a spinnaker block (on the toe rail at the transom), and then to a sheet winch you can increase the amount of snubber you deploy. You can release the snubber, giving you more snubbing, from the comfort of the cockpit, though you can only release the snubber by the amount of chain contained in your 'lazy loop' - so a more generous lazy loop gives you some wriggle room. You can store the 'excess' snubber as you would the tail of a sheet or halyard in a bag on the life lines or in the cockpit.

If you are looking to change the snubber, you think you need a storm snubber, but do not want to extend the rode (you have someone aft of you) you can grind the snubber in on the winch until the hook is just kissing the bow roller (from the comfort of the cockpit) and add a second snubber (though you will need your foul weather gear to add the storm snubber).

And or the skipper can do much of this leaving you to go to the bow.

Another option (actually I think the best chafe guard for everything that moves).
Two firemen hose, a large one (brown) and a smaller, stiffer one (red). The rope to be protected is tied to the red, internal hose, they move together. The brown hose sits over the roller and it is tied to it (or fairleads or whatever), it does not move WRT the boat.
As the snubber (or think JS drogue bridle) elongates, the red hose moves inside the brown one: there is no friction between rope and anything else, no friction against the roller either, it's all concentrated bewteen the two hoses. They are basically indestructible, the brown one has an inside aramid fabric, one needs a drill to make a hole in it, likewise the red one, which also takes a lot of effort to be bent. A lot better than simply stuffing the rope in a plastic water hose.
It's also rewarding to look at the whole thing while it is working
View attachment 179323

If access to fireman's hose is an issue - simply source some braided hollow Dyneema tape of two different sizes - dyneema is well known for being slippery. If you source braided dyneema hollow tape it also makes neat covers for soft shackles that might be used in abrasive environments.

Jonathan

 

[thinwater]

In the real world yes.
Slight wear has started, spare bearings separate from the roller which can be swapped out are, imho, a good idea & cost little.

I did know about nylon swelling but forgot it was so much.

The mists clear a little....

It's coming back to me now, I bought some acetal off a cruiser in Brasil ages ago & had a local fabrication shop sort out a better bolt & turn down the roller. Then it didn't get touched til the on deck snubber was fitted about a year ago.

So it is acetal. Another option - the axel is a M20 bolt fully threaded which is starting to wear the roller, 1" stainless seamless tube should fit over that pretty tight then get the hole in the roller reamed out so it's a slightly sloppy fit on the stainless. Also means I can crank up the bolt onto the cheek plates & tube, at the moment even though they're 6mm plate, crank the nut too much will bend themin a bit & jam the roller. Off to Faro tomorrow where there's a very big stainless stockist, he'll likely have some, maybe even in metric if such a thing exists.

The whole point of this was to get hold of any materials needed with the rare luxury of an address soon

And the spare acetol can be turned into sheaves to fit on deck for the snubber diversions at some point . It's slowly coming together, with very little involvement of the wallet

thnx all.

View attachment 179242

View attachment 179243

Just guessing, not knowing ...

If you have bearings at each end and no support in the center, the roller will gradually distort (bend) over time and load, no longer be straight, and won't turn. And there isn't room for a bearing support tube. That would send me back to the dawring board.

 

[GHA]

Just guessing, not knowing ...

If you have bearings at each end and no support in the center, the roller will gradually distort (bend) over time and load, no longer be straight, and won't turn. And there isn't room for a bearing support tube. That would send me back to the dawring board.

Possible, since it very rarely actually rotates it would be like a centre point load. though the bearing option was cast aside as a non runner already.
Looking a some seamless stainless hollow section to sleeve over the bolt & provide the running surface against the acetol, google seems to think that's a decent combination for low friction.

 

[vyv_cox]

Can you not replace the fully threaded bolt with one that is plain but threaded only at the end? Or does it need to be a bolt at all? It is quite common to have a length of round bar with split pins and washers outside the cheeks.

 

[thinwater]

Possible, since it very rarely actually rotates it would be like a centre point load. though the bearing option was cast aside as a non runner already.
Looking a some seamless stainless hollow section to sleeve over the bolt & provide the running surface against the acetol, google seems to think that's a decent combination for low friction.

Good idea. Also, make sure it is not too tight.

I like your outside-the-box thinking.

Another way is to slide tubular nylon webbing over the snubber, but do NOT fix the webbing to the snubber. The rope will slide inside the webbing with very little friction.

(The webbing is not fixed to the rope, and the bridle is around the back of the cleat only to ease the angle. The bridle anchors to the midships cleats to allow lots of stretch without being so long as to drag on the bottom.)

 

[GHA]

Can you not replace the fully threaded bolt with one that is plain but threaded only at the end?

Don't think so, without resorting to the wallet to get something fabricated - check post 21. The head of the M20 is already turned down a little to fit in a doubler plate welded onto the outside of cheek plate & the other end is similar but turned down to M10.
Sleeve would mean losing a little more material from the roller but only a few mm so prob no big deal.

Flimsy it ain't!

 

[DownWest]

Older than that is Oilite. Oil impregnated bronze usually used as a sleeved plain bearing insert. Bronze being good, strong,, wear resistant and corrosion proof boaty stuff it might be suitable. Check strength too.

Oilite are cintered; made from phospher bronze 'granules' pressed into shape, so naturally porous to hold the lube oil.

 

[DownWest]

I used 'plasticsonline' to buy my nylon and Tufnol, but I don't think they ship out of UK.

 

[thinwater]

Do the rollers on your (followers of this thread) boats actually turn under the load OP is describing? I'm pretty sure mine never did. When recovering chain (more friction) it did turn.

Has anyone experienced premature roller wear because the roller locked up on the pin? I have seen it, but it doesn't seem very common. Guessing.

Boat trailer rollers commonly seize, but they are polyurethane and are much higher friction. I have heard of trouble when some unknowing sailor replaced his bow roller with a trailer roller, because it looked similar enough.

--

Another risk to watch out for it running the snubber over the roller. If the chain rode is recovered under load over the snubber it can cause serious internal and unseen damamge, leading to failure in the very near future. Make sure you recover the snubber above the chain.

 

[Neeves]

Do the rollers on your (followers of this thread) boats actually turn under the load OP is describing? I'm pretty sure mine never did. When recovering chain (more friction) it did turn.

Has anyone experienced premature roller wear because the roller locked up on the pin? I have seen it, but it doesn't seem very common. Guessing.

Boat trailer rollers commonly seize, but they are polyurethane and are much higher friction. I have heard of trouble when some unknowing sailor replaced his bow roller with a trailer roller, because it looked similar enough.

--

Another risk to watch out for it running the snubber over the roller. If the chain rode is recovered under load over the snubber it can cause serious internal and unseen damamge, leading to failure in the very near future. Make sure you recover the snubber above the chain.

Ours turned up and down. As you imply - if it did not turn then there would be increased wear on the roller. This would engender a constant stream of threads on where to source new rollers for all and every yacht - and I don't recall the rollers of bow rollers being a major subject of posts.

Jonathan

 

[NormanS]

My twin bow rollers run on a common 1" s/s spindle with split pins at each end. I don't know the roller material, but it's some sort of white "plasticy" stuff. The idea of using a fully threaded bolt for a spindle, was inviting wear.

 

[thinwater]

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.

 

[Neeves]

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.

With a bridle you have other options including how the bridle itself is arranged.

I have only used a bow roller for a snubber on a monohull that had 2 bow rollers.

Using a fully threaded rod or fully theaded bolt would surely only be used when there was no immediate alternative, pending replacement later (and then forgotten)

Jonathan