Rick,
I think you have the picture. Touche's masthead main halyard sheave and sheave
box is the narrow V-sheave style. Touche', like many vintage C&C's had an all
wire main halyard and the wire winch with drum brake on the deck. When I
bought the boat I switched to a wire/rope halyard . I removed the wire winch
and the V-sheave box at the base of the mast. The mast base turning block is
now a Garhauer rope sheave block. I left the V-sheave at the masthead.
Changing out the V-sheave box at the masthead would involve widening the cut in
the mast, a process that would take an hour or two in a bosun chair. Just a
PIA to do. Not that it's a big deal, I've already spent 3+ hours aloft this
week installing a roller furler.
Touche's genoa halyard sheaves are the wider wire/rope sheaves you describe.
I'm running smaller, high strength, low stretch halyards on the genoa sheaves
(3/8 StaSet X Plus).
Dennis C.
Touche' 35-1 #83
Mandeville, LA
>________________________________
> From: Rick Brass <rickbr...@earthlink.net>
>To: 'Dennis C.' <capt...@yahoo.com>; cnc-list@cnc-list.com
>Sent: Thursday, May 9, 2013 11:51 PM
>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
>
>
>
>
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