Bow Roller Sheave

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Ian_Rob

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My 100mm dia x 57mm width, bow roller sheave has cracked and needs replacing. Versatile Marine on Ebay seems to turn them in a variety of materials including stainless steel. At present it is nylon or a similar synthetic plastic. I was thinking that a metal version would be longer lived and look better. Would it be significantly noisier in operation?
 
Ian_Rob said:
My 100mm dia x 57mm width, bow roller sheave has cracked and needs replacing. Versatile Marine on Ebay seems to turn them in a variety of materials including stainless steel. At present it is nylon or a similar synthetic plastic. I was thinking that a metal version would be longer lived and look better. Would it be significantly noisier in operation?
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I've quite often seen bronze rollers, so I don't see anything wrong with ss.
My previous boat had a metal bow roller, and noise was not a problem. Probably more expensive though.
 
Stainless will be ok but have it bushed in bronze.Stainless stell is a terrible bearing material and will grab or even gall on to the stainless spindle when under load.I would rather have it made in manganeze bronze which despite being only a high tensile brass is perfectly adequate for a bow roller.
 
The two original ones on my Sadler appear to be nylon. One of them is almost 30 years old. Both were replaced nearly 10 years ago with ones that have a central groove to take the chain and the shank of a Rocna or Delta on the starboard side, snubber to port. They seem to be Delrin or something similar.

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Tranona said:
Have one turned up from Delfin. Will last far longer than nylon. Don't see any benefit with SS
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Though a more maritime connection I think Tranona means Delrin. In fact it's better than any metal roller as it's water-lubricated. I've found metal rollers add lots of friction to lifting the anchor.
The last 2 I had turned from bar, in my local machine shop cost €5. Just make sure to have the correct size groove cut in the face to suit your 8, 10 or 12mm chain.
Polyoxymethylene it's better known as Acetal, Delrin being a trade name. Not to be confused with nylon which would be a very unsatisfactory bow-roller material, that swells when it absorbs water and does take flats.
 
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Thanks Charles -that's interesting. Direct Plastics is the cheapest supplier I have found so far. £25 for a 100 dia x 100mm length.
 
My present chain bow roller split into two, a few years ago. It split through the root diameter, so that it was like two narrow rollers on the one spindle. I made enquiries about a new one in Delrin, and was horrified at the cost. I glued the two halves together, and also drilled and bolted them together, with three lengths of 6mm threaded rod, suitably counterbored. It's been like that for several years, with heavy use, and is fine. May be a cheapskate possibility for the OP.
If I could have got a new one turned for £5, I certainly would, but I think the quote was nearer £100.:(
 
If it is £100, I'll enrol on an model engineering course at the local college (there 's one starting in January) and turn it myself.
 
Fairly sure I saw an eBay item which was an offer to machine bow rollers to your specified dimensions, for not too much money. Sadly I didn't save a link but I imagine a suitable search would find it.

Or maybe I should just buy the rod and visit my grandad to use his lathe.

Pete
 
prv said:
Or maybe I should just buy the rod and visit my grandad to use his lathe.
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Lucky you! Isn't it so annoying when people say things like 'just take it your friendly engineering shop and they'll do it for beer money'. They never tell you where this (mythical?) place is.

(I don't have a lathe, but occaisonally manage to turn something small on either the pillar-drill or the radial-arm saw - obviously supported unsatisfactoraly at one end only :( )
 
(I don't have a lathe, but occaisonally manage to turn something small on either the pillar-drill or the radial-arm saw - obviously supported unsatisfactoraly at one end only :( )[/QUOTE]

I have also turned on my pillar drill but I'm always concerned I'm damaging the bearings applying lateral loads?
 
Ian_Rob said:
Thanks Charles -that's interesting. Direct Plastics is the cheapest supplier I have found so far. £25 for a 100 dia x 100mm length.
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I must confess that I had the job done by the machine shop in Messolonghi town - he had the necessary 60mm bar and the lathe (an old 10" Cincinnati). Buying acetal bar in small quantities is likely to prove fairly expensive and I think you have a pretty fair price. The one time I had 4 acetal rollers, for my lifting keel, machined in the UK I was suitably horrified by the 3-figure price quoted. The stuff is a delight to machine (you could do it on a wood-turning lathe) providing you keep the speed down.
Despite the scoffing post don't be put off getting it done locally, I can't expect you to go to Greece to have it machined by Angelos. He speaks no English, but Dad speaks Italian, and can actually follow a drawing accurately. He's done lots of machining and fabrication jobs for me during the past 3 years, always for peanuts, with immense ingenuity and impeccable reliability.
 
2 quotes so far:

Local Metalworker - £108.60 inc VAT but excluding delivery.
Ebay - £47.94 (or £77.94 if I want a second one as a spare) inc VAT & delivery.

Both for Delrin.
 
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Ian_Rob said:
2 quotes so far:

Local Metalworker - £108.60 inc VAT but excluding delivery.
Ebay - £47.94 (or £77.94 if I want a second one as a spare) inc VAT & delivery.

Both for Delrin.
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E-Bay price looks quite good - one has to allow for setting-up time.

I find rollers last about 6 years, but I anchor at least 100 times/year - using a textile snubber helps a lot in saving wear (it also transformed how the boat lay to anchor and dramatically reduced
dragging) I use 3-10m of 14mm Octoplait through one of the forward fairleads.
 
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