Anchor Roller Refurbishment?

[Yngmar]

However, I did find a picture of a similar roller on another boat. This had about a 10mm gap either side of the swivelling part and the fixed box, and no spacers! Any reason I can't make the whole lot narrower?

The swivel axle will have to bear the load a bit further from the bracket (which is probably fine) and needs some spacers to center the swivel in the bracket, otherwise I see no reason why not. It's plenty wide presumably because the CQR's fat hinge had to fit in there. Your Bruce will fit fine into a narrower bracket and so will any of the newer designs I've seen. You'll also have to remove the bar of course, but then that's not much more work.

Make sure all of your ground tackle bits will still run through though before you make it narrower, incl. the D-shackle pin (if you haven't switched to a flush pin shackle with Loctite, which would sort this).

 

[Neeves]

As Ynmar says you need to ensure all the components match for size and strength so maybe you need to re-check but if everything is of the correct strength then narrowing the rotating assemble will slightly reduce the load on the axles anyway, as they will be shorter. I think dispensing with the counter sunk heads will be another advantage, as countersinking might introduce a less strong point. If you then revert to a bolt, instead of the shaft, you will reduce the work you need to do, just use a bolt and nut on the other end.If you are narrowing the rotating assemble you need to reduce the length of the other shafts and they can also be bolts. You now go back to finding bolts with a short threaded portion so that the rollers run on an unthreaded section.

It appears from an earlier image that you do not use the full width you currently have available, the horizontals of the old roller look unworn and just look like spacers, having the space on the outside, of the rotating portion, seems to solve quite a few problems.

Do you get wear on the main bolt, on which the whole thing rotates, it would be nice to have hollow shaft so that the wear is evened out.

If you are doing all this then maybe cut the head (protrusion) off the correctly sized (for size and strength and that fits the chain, anchor and roller spacing) bow shackle, Crosby or Peerless Grade B, and secure with Loctite. I cannot suggest you consider a 'D' shackle.

I had wondered how you were going to achieve all of this as you are in the UK, the bow roller (I assume) is down off the African coast - maybe you have a full engineering workshop on board. But quite a conversion to achieve limited by 'on board' resources.

Best wishes,

Jonathan

 

[noelex]

Flush fitting bow roller axles like this are not uncommon on pivoting bow rollers. The usual construction method is something like this:

The advantage of this design is that the bolt and washer only act to prevent the axle moving laterally. The weight is taken by the full thickness of the axle.

The bolt can therefore be quite small.

 

[Neeves]

Flush fitting bow roller axles like this are not uncommon on pivoting bow rollers. The usual construction method is something like this:

The advantage of this design is that the bolt and washer only act to prevent the axle moving laterally. The weight is taken by the full thickness of the axle.

The bolt can therefore be quite small.

If the only item holding the two plates is the axle then if there is any side load small bolts will simply shear. In many bow rollers the axle is part of the structure. I have seen too many distorted bow rollers. In Nigel's case the axle roller is just one component holding it together.

Jonathan

 

[noelex]

If the only item holding the two plates is the axle then if there is any side load small bolts will simply shear. In many bow rollers the axle is part of the structure. I have seen too many distorted bow rollers. In Nigel's case the axle roller is just one component holding it together.

Jonathan

Yes I agree some bow rollers are not strong enough for extreme conditions. This one seems to have stood the test of time but unfortunately its design makes replacement of the rollers difficult. Rollers do wear out so really need to be easily replaceable.

I think most of the lateral load would be taken by the thicker stainless steel cheeks of the fixed part of the bow roller together with the end pin. So I'm not sure a more conventional, easily removable, axle as shown in my diagram would create any problems but a relatively easy modification would be to weld bottom plate on the lower floor of the pivoting part. As shown in red. This would help remove any concern about lateral loads affecting the axles and strengthen the whole structure.

 

[nigelmercier]

Not really possible to use bolts. The axles also have to seperate the side plates, so need a reducing step before passing through. I could sleeve them, but if the sleeves started to rotate it would be a mess.

 

[sarabande]

Roger

you put up a pic earlier. Any chance of some more pics to show the solution you arrived at please ?


many thanks

 

[rogerthebodger]

Roger

you put up a pic earlier. Any chance of some more pics to show the solution you arrived at please ?


many thanks

If its me you are asking just got back from a trip to the bush so hear goes.

These are all the pics I have showing the bow roller and fittings.

I did not go for a nodding donkey nose as the strength of the roller axles are a comprise, its overly complicated and both my anchors stow automatically with the said at a turnover banana/boomerang device. I was also looking for maximum strength for anchoring in rough conditions.

I also have an attachment for a removable bow mounted ladder and a removable bowsprit that can be seen in some of the pics.

 

[nigelmercier]

I understand and I think 16mm dia axle is great...

Update on completed unit. I increased the axles to 16mm, narrowed the whole swivel unit by 4mm to allow for a small protrusion of the screw heads and made 2mm washers out of acetyl.

 

[rogerthebodger]

Nice job Nigel.

Did you remake the side plates or use the existing and polished then up.

The screws in both ends of the axles not only located then horizontally but also prevents the from rotation which is a desirable feature to stop the axles rotating and wearing the hole in the side plate oval.

 

[nigelmercier]

Existing side plates, plus orbital sander. I'd like to polish them, but not sure of best product.

 

[rogerthebodger]

Existing side plates, plus orbital sander. I'd like to polish them, but not sure of best product.

Polishing soap here

http://www.ebay.co.uk/bhp/polishing-soap

and here

http://www.hollisonsupply.co.uk/metal-polishing-supplies/polishing-compounds.html

I polish down to 240 or better 320 grit flap wheel but you could use your orbit sander, just may take longer

then I polish with this setup up but you could put a polishing mop on a bench grinder. A normal drill does cannot take the side loading needed for polishing

and these

This web site gives lots of info on polishing with different buffs and compounds.

http://www.caswellplating.com/buffman.htm