Furler swivel

[deeb]

I need a swivel for the top end of a torsion cable - anything considered - this is not a high load application, and not marine or in anyway safety critical, just something that'll still go round round with 20 or so kilos of load applied.

The lack of information is a result of the brief being quite wide....

 

[penfold]

Torsion cable? I don't know what that is, most cables cannot carry much torsion without incurring damage. What is the swivel doing?

 

[deeb]

Torsion cables are designed not to twist (think in terms of halfway between a cable and a rope) - they're used in Code type sails where ther furler is mounted at the bottom, the sail is attached to the cable and with a swivel (the bit I'm looking for) at the top. Apply turns to the furler and the sail rolls up. When you've finished you drop the rolled sail to the deck, fold it into a bag, and that's yer job.

What I need is a fitting that'll carry a smallish load, but still allow the cable to rotate.

 

[penfold]

One of these do?

 

[deeb]

sort of. It's that function but I think I'll need a bit more load capability- I had in mind something with bearings so it run's free. My experience of thosse types of fittings is that they a bit crude - I'd like a really sweet friction free motion, without being meg fussy....

 

[penfold]

Barton top swivel; that's about as good as you'll get short of going to harken and being charged 10 times as much.

 

[deeb]

Well kinda, yes. I was hoping a part of some redundant headsail set (off a bit of a larger boat than you are thinking), that given attachments and bearings I could adapt to my project. I know such things exist, I have seen them in marina skips in all corners. If I was to go shiny new and proprietary route, I imagine it'd cost 100s. I'm looking to support the luff of a heavyish cloth, 8.5m forestay length., anything that'l go round with a load through axis. Barton fitting is cheap enough, I'll see if they do something a bit lumpier. Thanks!

 

[penfold]

It's rated to a tonne; how much sailcloth are you hanging?

 

[deeb]

Its about the tension - in this application the 'luff' will lie horizontally, and is just short of ten metres- I shall need this to lie realtively straight so will need to wind it up a bit. The "sail" hanging from this is only about three meters - think in terms of of a roller blind. If sag becomes a problem I may be able to introduce an inermediate support., but would rather not. I have a massive furler that came off a staysail on a volvo 70 - smashed pretty well to bits- butI have repaired it and now it operates well, I was trying to find something similarly (doesn't have to be exactly) butch for the other end. Sorry if I've not been explaining myself well. In the end I can get a thrust bearing and make a housing / shaft and it may be this is the way to go, but I have seen suitable items in marina skips in the past.

 

[penfold]

Without quantifying how much sag you can live with, how heavy the 'sail' and wire weigh in total and most importantly how much tension the structure you're attaching this to can take before breaking, this is just a series of wild-a**ed guesses; if this is going anywhere public you need to get a bit surer about things. A 30' wide retractable canopy certainly sounds like that.

 

[deeb]

That's me told then. I'm very sorry to have wasted your time. You could of course not have bothered.

 

[penfold]

You post something on a discussion forum and it's discussed, that's how it works.

 

[deeb]

Er, No. These are want ads. If I'd wished to enter a design for discussion I'd have put it in scuttlebutt or somewhere a bit techie. I was simply looking to source second hand a component that I know gets discarded fairly regularly by yachtsmen / riggers. I wasn,t looking for suggestions as to which commercially available fitting I could buy, or even to be drawn in to explaining to the un-initiated what function is served by a torsion cable. Even less was I looking to have my un-submitted design critiqued as wild-a**ed. Its a want-ad. You post the ad, someone who has such a thing surplus to their needs can contact you: that's how it works.

I'll leave the last word, if you want it, to you: I'm out.