Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 13-05-2015, 20:28   #1
Registered User

Join Date: Oct 2014
Location: Hamilton, NZ
Boat: Bonito Aquarius 22
Posts: 29
main halyard help needed

Hi, I recently changed the wire main halyard for a 6mm dyneema rope. But the masthead doesn't take a sheave big enough for the 6mm rope. The largest diameter sheave it takes is 8mm, not really big enough for the rope. I've thought about removing the sheave and just running the rope around the clevis pin, or using 4mm dyneema rope for halyard.

The boat is a 22ft trailer sailer used for cruising in light to moderate conditions in mostly sheltered areas.

I notice that some boats have rope halyards, but cant see the masthead clearly in photos, I wonder how others get round the problem. Any help or comments is much appreciated.

Many thanks
__________________

__________________
amoret is offline   Reply With Quote
Old 13-05-2015, 20:37   #2
Registered User
 
RainDog's Avatar

Join Date: Jun 2009
Location: Varies
Boat: Pacific Seacraft 34 #142
Posts: 1,183
Re: main halyard help needed

4mm is certainly plenty strong. You would not want to pull on it worth your hands. I assume you are replacing a wire to rope halyard? Could use 4mm Dyneema for the part that was wire, and a more hand friendly line for the pay you pull on and cleat off.
__________________

RainDog is offline   Reply With Quote
Old 13-05-2015, 21:02   #3
Senior Cruiser
 
roverhi's Avatar

Cruisers Forum Supporter

Join Date: Aug 2005
Location: Kona, Hawaii, Carlsbad, CA
Boat: 1969 Pearson 35 #108 & 1976 Sabre 28
Posts: 6,003
Send a message via Yahoo to roverhi
Re: main halyard help needed

6mm is smaller than 8mm. Was there a typo in your posting?? If the old halyard was wire spliced to rope, the Mast head sheave should take the same diameter line as the old rope portion of the former halyard. Unless you had a wire reel winch, which is doubtful on a boat your size, the sheave has got to be able to take more than 4mm line which is something like 3/16". In any case, 4mm Dyneema is more than strong enough.
__________________
Peter O.
'Ae'a Pearson 35
roverhi is offline   Reply With Quote
Old 14-05-2015, 04:07   #4
Registered User

Join Date: Oct 2014
Location: Hamilton, NZ
Boat: Bonito Aquarius 22
Posts: 29
Re: main halyard help needed

thanks for the suggestion Raindog. Probably the best thing to do. What do you think about the idea of removing the sheave and just running the 6mm rope around the clevis pin? ( I've already bought and installed the 6mm rope)
__________________
amoret is offline   Reply With Quote
Old 14-05-2015, 04:13   #5
Registered User

Join Date: Feb 2013
Location: Sydney
Posts: 13
Re: main halyard help needed

Make a tip splice in the halyard. That is removing the cover of the rope so that at max hoist the cover is just through the jammer. This will reduce the line size around the sheave and run much better. Removing the sheave totally is not recommended. I would replace the sheave with an acetyl one and clean the axel. A sheave is worth about $40.


Roland

Sent from my iPhone using Cruisers Sailing Forum
__________________
Roland Schmidmaier
Tempo Spars Yacht Masts and Rigging
www.tempospars.com
Tempo Spars is offline   Reply With Quote
Old 14-05-2015, 04:17   #6
Registered User

Join Date: Oct 2014
Location: Hamilton, NZ
Boat: Bonito Aquarius 22
Posts: 29
Re: main halyard help needed

Hi Peter, thanks for the reply. 8mm is the outer width of the sheave, ( 6mm on the inside ) the 6mm rope pinches in the sheave which is really only recommended for 2-4mm rope. The rope part of the old rope/wire halyard was 8mm and never got out of the mast head. (so big at the join it wouldn't pass through the top of the tapered mast)
__________________
amoret is offline   Reply With Quote
Old 14-05-2015, 08:09   #7
Registered User
 
RainDog's Avatar

Join Date: Jun 2009
Location: Varies
Boat: Pacific Seacraft 34 #142
Posts: 1,183
Re: main halyard help needed

Quote:
Originally Posted by amoret View Post
thanks for the suggestion Raindog. Probably the best thing to do. What do you think about the idea of removing the sheave and just running the 6mm rope around the clevis pin? ( I've already bought and installed the 6mm rope)
No harm in trying it. Dyneema can handle the extreme bend and is very slippery. Just keep an eye out for chafe.
RainDog is offline   Reply With Quote
Old 14-05-2015, 09:32   #8
Registered User

Join Date: Apr 2015
Posts: 12
Re: main halyard help needed

Sorry I am a rope maker and Dyneema DOES NOT like tight bends. leave the sheave in place. Yes its slippery but the loss in strength just going around a sheave would be greater then 50%
__________________
CRANBERRY is offline   Reply With Quote
Old 14-05-2015, 09:45   #9
Registered User
 
RainDog's Avatar

Join Date: Jun 2009
Location: Varies
Boat: Pacific Seacraft 34 #142
Posts: 1,183
Re: main halyard help needed

6mm dyneema at 50% strength will still be strong enough to lift his entire boat out of the water with room to spare.
RainDog is offline   Reply With Quote
Old 14-05-2015, 10:03   #10
Registered User

Join Date: Sep 2013
Location: Alert Bay, Vancouver Island
Boat: 35ft classic ketch/yawl.
Posts: 931
Images: 4
Send a message via Skype™ to roland stockham
Re: main halyard help needed

Sorry but this makes no sense 8mm diameter sheave??? that would take a wire size of 1mm and rope less than 1.5mm. 6mm low stretch ropes like a sheave diameter of 5-7x the rope diameter. Bigger is better. Running a rope over the spindle will trash everything and have the same effect as running over a blunt knife.
Sizing hallyard is about handling so the don't cut your fingers off, wear at the blocks and 'creep' - to light and stretchy and the luff will keep going slack. The load on a small boat is minimal but is bases on sail area 3-4mm rope should be fine. To big a diameter is going to make it much harder to hoist
__________________
roland stockham is offline   Reply With Quote
Old 14-05-2015, 10:33   #11
Registered User

Join Date: May 2012
Location: Central California
Boat: Catalina 30
Posts: 873
Re: main halyard help needed

Can you get a wider delrin sheeve and sand it
narrower to fit?
__________________
Bill
...........................................
You can't buy happiness, but you can buy ribeye.
jongleur is offline   Reply With Quote
Old 14-05-2015, 11:02   #12
Registered User

Join Date: Jan 2010
Location: Narragansett Bay
Boat: Able 50
Posts: 3,057
Re: main halyard help needed

The old halyard would probably have included either 3mm or 4mm 7x19 SS wire. The 3mm has a break load around 500kg and the 4mm around 900kg. 5mm Amsteel Blue has a BL around 2200kg while 4mm is around 1700kg.

I suggest using the 5mm because it will stretch less but the 4mm would certainly work. The weight difference is inconsequential.


You might consider stripping the cover from a thicker Dyneema SK75 rope of 7 or 8mm.
__________________
savoir is offline   Reply With Quote
Old 14-05-2015, 11:07   #13
Registered User

Join Date: Jan 2010
Location: Narragansett Bay
Boat: Able 50
Posts: 3,057
Re: main halyard help needed

Quote:
Originally Posted by roland stockham View Post
Sorry but this makes no sense 8mm diameter sheave??? that would take a wire size of 1mm and rope less than 1.5mm. 6mm low stretch ropes like a sheave diameter of 5-7x the rope diameter. Bigger is better. Running a rope over the spindle will trash everything and have the same effect as running over a blunt knife.
Sizing hallyard is about handling so the don't cut your fingers off, wear at the blocks and 'creep' - to light and stretchy and the luff will keep going slack. The load on a small boat is minimal but is bases on sail area 3-4mm rope should be fine. To big a diameter is going to make it much harder to hoist
He means " width ".
__________________
savoir is offline   Reply With Quote
Old 14-05-2015, 11:37   #14
Marine Service Provider
 
fkittson's Avatar

Join Date: Jan 2012
Location: Port Credit Ontario, Canada
Boat: 1978 Alberg 30
Posts: 212
Re: main halyard help needed

We have a Alberg 30 that had wire rope halyards. We have just done the switch to amsteel rope 3/16 spliced to a 3/8 tail. We measured the old halyard when stores at the bow pulpit and added 16" to that. Then spliced 3/8 the rest of the way to the clutch. The 3/16 Amsteel rope is actually stronger the SS Wire and you can still use the old wire V shives. Just make Shute whoever splices it knows what they are doing. At .90 per foot is not that cheep.


Sent from my iPhone using Cruisers Sailing Forum
__________________
fkittson is offline   Reply With Quote
Old 14-05-2015, 14:18   #15
Registered User

Join Date: Oct 2014
Location: Hamilton, NZ
Boat: Bonito Aquarius 22
Posts: 29
Re: main halyard help needed

Umm yes, sorry 8mm width sheave
__________________

__________________
amoret is offline   Reply With Quote
Reply

Tags
halyard

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
main halyard 2:1 purchase ? how ? gramos Deck hardware: Rigging, Sails & Hoisting 7 11-08-2008 06:27
wire main halyard going up the mast shellback Deck hardware: Rigging, Sails & Hoisting 5 19-06-2007 01:57
Main Halyard - Snap Shackle?? markpj23 Deck hardware: Rigging, Sails & Hoisting 10 07-06-2007 09:42
main halyard Capt.Shaggy Meets & Greets 4 13-03-2006 14:57
main halyard replacement kingfish Construction, Maintenance & Refit 12 24-08-2004 00:23



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 04:26.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.