What size halyard line should I use on M-17?
Hello all, my 1987 M-17 came with rope/steel wire halyards when I bought it about 15 years. About 11 years ago I decided to replace the halyards, and I used StaSet 5/16" line going both up and down the mast. Unfortunately I did not replace the masthead blocks (sheaves?) that the old steel cable went through, and over time the halyards became frayed. Now one of them has become unusable. I need to replace the halyards, and was wondering if 5/16" line is not overkill. I was hoping to conduct an unscientific poll: what size halyard line is on your M-17? I was thinking of going down to 1/4" to make the line run smoother through the blocks. Also, does anyone know what size masthead blocks do I need to replace the existing ones that are intended for wire? Is there a good source for these? Thanks,Andrei.
The thing about line diameter is that it can vary between manufacturers for a given stated size. In other words, not al line identified as 5/16 will be the same diameter. I can't find the source right now but I read this somewhere in a faq about rope & line, including (maybe especially) double braid. It has something to do with weight per length, or volume...anyhow, some 5/16 will be a tiny bit thicker, or thinner, than others. Same for any other stated size. I have seen this myself with line from different manufacturers. So if you had slightly 'fat' 5/16 it might chafe on the sheaves whereas if you had slightly 'thin' 5/16 it might not. My halyards on my M17 are I am pretty certain 5/16" nominal size. But the sheaves appear to be sized for that. So maybe the OEM on my boat was all line. It's #38 from 1974 if Jerry or anyone else can speak to what the OEM halyards were then. cheers, John On 6/21/21 8:07 AM, Andrei Caldararu via montgomery_boats wrote:
Hello all, my 1987 M-17 came with rope/steel wire halyards when I bought it about 15 years. About 11 years ago I decided to replace the halyards, and I used StaSet 5/16" line going both up and down the mast. Unfortunately I did not replace the masthead blocks (sheaves?) that the old steel cable went through, and over time the halyards became frayed. Now one of them has become unusable. I need to replace the halyards, and was wondering if 5/16" line is not overkill. I was hoping to conduct an unscientific poll: what size halyard line is on your M-17? I was thinking of going down to 1/4" to make the line run smoother through the blocks. Also, does anyone know what size masthead blocks do I need to replace the existing ones that are intended for wire? Is there a good source for these? Thanks,Andrei.
-- John Schinnerer - M.A., Whole Systems Design -------------------------------------------- - Eco-Living - Whole Systems Design Services People - Place - Learning - Integration john@eco-living.net - 510.982.1334 http://eco-living.net http://sociocracyconsulting.com
Andrey, I bought a 1974 M17 that needed work a couple years ago. The mast had somehow gotten damaged (tree? bridge?). Anyway, I bought a new one from Dwyer Mast, along with all associated hardware. Perhaps you can look at the profiles and see if your mast head is the same. I went with 5/16, it’s going on two years now with no chafe. I’d also think any machine shop could make a set of sheaves for you if you can tell them what you need. https://www.dwyermast.com/items.asp?cat1ID=20&cat1Name=Masts&familyID=40&fam... -Gerry
On Jun 21, 2021, at 12:20 PM, John Schinnerer via montgomery_boats <montgomery_boats@mailman.xmission.com> wrote:
The thing about line diameter is that it can vary between manufacturers for a given stated size. In other words, not al line identified as 5/16 will be the same diameter.
I can't find the source right now but I read this somewhere in a faq about rope & line, including (maybe especially) double braid. It has something to do with weight per length, or volume...anyhow, some 5/16 will be a tiny bit thicker, or thinner, than others. Same for any other stated size.
I have seen this myself with line from different manufacturers.
So if you had slightly 'fat' 5/16 it might chafe on the sheaves whereas if you had slightly 'thin' 5/16 it might not.
My halyards on my M17 are I am pretty certain 5/16" nominal size. But the sheaves appear to be sized for that. So maybe the OEM on my boat was all line. It's #38 from 1974 if Jerry or anyone else can speak to what the OEM halyards were then.
cheers, John
On 6/21/21 8:07 AM, Andrei Caldararu via montgomery_boats wrote: Hello all, my 1987 M-17 came with rope/steel wire halyards when I bought it about 15 years. About 11 years ago I decided to replace the halyards, and I used StaSet 5/16" line going both up and down the mast. Unfortunately I did not replace the masthead blocks (sheaves?) that the old steel cable went through, and over time the halyards became frayed. Now one of them has become unusable. I need to replace the halyards, and was wondering if 5/16" line is not overkill. I was hoping to conduct an unscientific poll: what size halyard line is on your M-17? I was thinking of going down to 1/4" to make the line run smoother through the blocks. Also, does anyone know what size masthead blocks do I need to replace the existing ones that are intended for wire? Is there a good source for these? Thanks,Andrei.
-- John Schinnerer - M.A., Whole Systems Design -------------------------------------------- - Eco-Living - Whole Systems Design Services People - Place - Learning - Integration john@eco-living.net - 510.982.1334 http://eco-living.net http://sociocracyconsulting.com
Andrei: 5/15" for the job halyard and 1/4" for the main. Was halyard that became damaged from rubbing in burrs? Rubbing against the masthead fitting? Other? Modern line is very strong and low stretch so if your hand is comfortable using 1/4" that is ok for the jib halyard. 5/16" will be easier on the hand and have lower stretch (as using less of its working load v 1/4"). Jerry, like all boat builders back in the 70s and 80s used wire or rope-to-wire for decreased stretch. There days just isn't necessary. Wire blocks can be used with rope. Wire can't be used in blocks made for rope. :: Dave Scobie :: M6'8" #650 :: SV SWALLOW - sv-swallow.com :: former owner M17 #375 SWEET PEA - m17-375.com :: former owner M15 #288 SCRED - m15namedscred.wordpress.com <<-- new site! On Mon, Jun 21, 2021, 8:09 AM Andrei Caldararu via montgomery_boats < montgomery_boats@mailman.xmission.com> wrote:
Hello all, my 1987 M-17 came with rope/steel wire halyards when I bought it about 15 years. About 11 years ago I decided to replace the halyards, and I used StaSet 5/16" line going both up and down the mast. Unfortunately I did not replace the masthead blocks (sheaves?) that the old steel cable went through, and over time the halyards became frayed. Now one of them has become unusable. I need to replace the halyards, and was wondering if 5/16" line is not overkill. I was hoping to conduct an unscientific poll: what size halyard line is on your M-17? I was thinking of going down to 1/4" to make the line run smoother through the blocks. Also, does anyone know what size masthead blocks do I need to replace the existing ones that are intended for wire? Is there a good source for these? Thanks,Andrei.
participants (4)
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Andrei Caldararu -
Dave Scobie -
Gerry Lempicki -
John Schinnerer