I changed out my mast and boom sheaves after 16 years because they were worn out from use and sun exposure, cracked, chipped, etc.
Certainly at the mast head, these plastic sheaves take a lot of sun exposure, at least in NC. Charlie Nelson Water Phantom C&C 36 XL/kcb cenel...@aol.com -----Original Message----- From: Rick Brass <rickbr...@earthlink.net> To: 'Dennis C.' <capt...@yahoo.com>; cnc-list <cnc-list@cnc-list.com> Sent: Fri, May 10, 2013 12:51 am Subject: Re: Stus-List Spectra/double braid halyards Dennis, please explain the comment about changing out the sheaves and sheave boxes. Both my 25 and 38 – which are about the same vintage as Touche’ – had wire to rope halyards. The sheaves were the type with a curved shape for the rope and a small curved groove for the wire. Not the type with a v-shaped grove you see in some sheaves. I converted to all rope (3/8” in the 25 and 7/16” on the 38 – StaSet in both cases) halyards and have seen no deformation or chafe in the halyards in 10 years of use on the 38, and more like 15 on the 25. Plus the StaSet is just about as strong as the wire part of the wire to rope halyards I replaced. If you have the “round groove” type of sheaves, I wonder if you would need to change them. In the last few months I’ve bought two sets of spin sheets made of Dyneema or Dyneema/MFP blend. Both the 3/8 Salsa sheets and the 5/6 light air Flight-Line sheets are far stronger than I really need, but they float – which will avoid reoccurrence of an expensive prop shaft and engine repair that resulted from my last set of non-floating sheets. I’ve been thinking that my next halyard purchase will also be Dyneema. I don’t know what diameter the wire in your current halyard is, but here is a comparison of strength of Samson AmSteel Blue with 1x19 304 stainless wire for running rigging: Diameter Amsteel 304 Wire 5/32 3600 2500 3/16 4900 3700 ¼ 7700 6400 Of course 304 wire is stronger than 316 wire of the same diameter. Amsteel Blue can be routed around sheaves with a diameter 8 times the line diameter, so 2” sheaves will do. Amsteel Blue has elongation of 0.96% at 30% of break strength, while the wire varies from 2.3% for 5/32 to 2.4% for ¼”. There is a line supplier in Pennsylvania from whom I have bought a considerable amount of running rigging over the years (I used to live in the next town over from his warehouse). He’s reliable and Samson dealer. He has ¼” 12-plait Dyneema SK75 halyard line on EBay right now for $0.90 per foot. I don’t think it is Samson, but it appears to be functionally identical. So I paid $1.60 something a foot for StaSet with a break strength of 7000 pounds. The stuff has elongation over 2% at 20% load. Or I can buy Dyneema that is 10% stronger and about a third the weight ( plus being lighter, 20% stronger, and less than half as stretchy as the wire in the original halyards) for about half the cost of StaSet. And splicing 12-plait Dyneema is child’s play, a lot like splicing a poly ski rope, so I did it myself on the sheets I made from Salsa line and saved that cost. I know I can’t run the ¼ inch line through my cabin top rope clutches. But given the strength and low stretch, I don’t see it as a problem to use the winch and the companion horn cleat mounted on the mast to raise and secure the halyard. It seems like Dyneema halyards are a pretty good option. At least as long as there is not something that would require a change to the mast sheaves. Hence my question at the top of this long and rambling message. Rick Brass Washington, NC From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Dennis C. Sent: Thursday, May 09, 2013 9:37 AM To: cnc-list@cnc-list.com Subject: Re: Stus-List Spectra/double braid halyards I've been considering a Dyneema/StaSet main halyard for the same reason but I will talk with APSLtd instead of Cajun. To switch to an all rope, one size halyard, I'd have to change out the sheave and sheave box. Not sure I want to spend an hour cutting out the opening in the mast to accommodate a wider sheave box. Dennis C. Touche' 35-1 #83 Mandeville, LA _______________________________________________ This List is provided by the C&C Photo Album http://www.cncphotoalbum.com CnC-List@cnc-list.com
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