Difference Dyneema versus Polyester Halyard in real life

Simply the main halyard has to deal with a lot more dynamic weight whilst sailing.
Once you released your topping lift the halyard takes the weight of the sail and the boom.
Up wind, the halyard has to take the downward pull due to the main sheet.
On a reach and run the kicker takes over.
Most important is when your main sheet is cleated or off the wind the kicker is on, every time there's a gust one of three things happen,
1, The boom lifts, twisting the leach and venting power. (stopped by the mainsheet and/or the kicker)
2, The halyard stretches twisting off the leach and venting power. (Dyneema halyard reduces this)
3, The gust powers the sail up and you go faster without loosing power. (cruisers substitute "go faster" with "More efficient")
 
I've gradually replaced all my polyester halyards with UHDPE ones 2mm less diameter. The smaller diameter significantly reduces friction on ropes brought back to the cockpit.
There is far less stretch (after the initial creep).
The oldest, now 25 years old spinnaker halyard, has worn slightly better than polyester. My main halyard was Kevlar - which I cannot recommend, because of sudden fatigue failure.
What you do need to watch is the added wear on jammers, ring types like Lewmar and Spinlock fare well but serrated ones such as Rutgerson, Barton and Easylock are prone to wear and fail to hold the halyards.
My single line reefs and the leach tails are also now UHDPE also - mainly due to the smaller diameter/easier running rather than just lack of stretch.
 
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I too am looking at changing the main halyard for dyneema but after having one where the cover wore out in the clutch area after just 2 months sailing I am wary of the cover wear on a dyneema line .
The cover slipped easily as well defeating the object of a non stretch halyard .
Which is the best dyneema line for minimal wear of the cover in
clutches ?
 
In post #25 you suggested using Dyneema to make the topping lift smaller. I did something like this a few years ago and was surprised to find one day that it was now capable of catching in the jamming cleats for the leach line. I learned this when attempting to lower the main in the dark off Ijmuiden in plenty of wind, when the line caught at the first reef point.
 
>With the greatest of respect, I would suggest that if you have sailed 10000 miles & not adjusted your halyard ( apart from reefs, drops & hoists I assume) you really do not understand the effect of tension on the sails. So that would suggest that your comments are without informed basis so should not really be taken as expert advice just because it suits you.
But with 10000 miles under the belt it does suggest that you are a sailor of some ability -just one who has other priorities

Top put it into context across the Atlantic we sailed 2,935nms with a reefed mizzen, twin headsail twistle rig and polyester rope halyards. I can assure you we never had the tighten the halyards, if you don't believe me try it.
 
Its not a question of tightening the halyards.
A tight halyard is the wrong way to look at it.
Once the sail is up, its up.

Like a jib sheet, you pull a sheet to a point. not too loose and not too tight.

For example you could hoist your sail using thick elastic as a halyard.
The sail can be pulled right up and cleated of.

When the sail is sheeted in imagine what would happen.
The head of the sail would be pulled down the mast a few inches and when the wind eases off the head of the sail would go back up.
No need to adjust the Halyard in that case either.
It would be kind of an automatic system for de-powering your rig.

(oooh invented a new reefing system :))

Well all other ropes we use for halyards will do the same thing as elastic only less so.
and that includes Dyneema as it will do the same thing as any rope only less like elastic than polyester.

In answer to a PM,
Yes your jib sheet will stretch in the same way, decreasing power of your sails.
However we tend to over size our sheets to make them easier to handle which in turn provides a stronger and less stretchy rope.
Like the racing boys you could change over to dyneema for your sheets as well for a performance improvement.

On the wear issue of clutches and the like using dyneema.
The issue here is what processes and material the manufacturer uses for the construction of the rope cover.
Whilst the dyneema essentially comes from the same place the cover will vary a lot from one manufacturer to another.
My current favorite is English Braids but it used to be Liros and before that Marlow.
Marlow and English braids are owned by the same holding group and even share manufacturing for some ropes but even then there's a difference.

On the topping lift issue I have a short length of elastic at the boom end to around a couple of feet up the topping lift so when its eased off the elastic takes up the rope slack but nowhere near enough to effect the boom.
 
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The converse also happens.
If your halyard tension is good in a breeze, as the wind drops and you ease the sheet, the halyard can over-stretch the luff as it shrinks.
 
I was thinking about the benefits of a dyneema main halyard and wondered whether also appropriate for slab reefing lines- the leech lines running back to the cockpit are also pretty long and have the potential to stretch; perhaps a good argument for looking for a big reel of the stuff on ebay.
 
eddystone said:
I was thinking about the benefits of a dyneema main halyard and wondered whether also appropriate for slab reefing lines- the leech lines running back to the cockpit are also pretty long and have the potential to stretch; perhaps a good argument for looking for a big reel of the stuff on ebay.
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We recently added a third reef and used "cruising dyneema", bought on eBay for the purpose - was thinner than would otherwise need which reduced friction, weight and windage with this long reef line
 
dunedin said:
We recently added a third reef and used "cruising dyneema", bought on eBay for the purpose - was thinner than would otherwise need which reduced friction, weight and windage with this long reef line
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I bought some that stuff once. It melts with a hot knife just like polyester does. Proper Dyneema doesn't. Not convinced that it isn't a con.
 
eddystone said:
I was thinking about the benefits of a dyneema main halyard and wondered whether also appropriate for slab reefing lines- the leech lines running back to the cockpit are also pretty long and have the potential to stretch; perhaps a good argument for looking for a big reel of the stuff on ebay.
Click to expand...

Yes, definitely. Having all the lines the same colour may not be ideal though.
 
AngusMcDoon said:
I bought some that stuff once. It melts with a hot knife just like polyester does. Proper Dyneema doesn't. Not convinced that it isn't a con.
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Yes, always a risk buying cheap on eBay that don't get what you expect. So far the cruising dyneema I have bought there seems to be the right stuff - with proper dyneema core, as far as I can tell (the cover tends to differ by brand)
 
dunedin said:
Yes, always a risk buying cheap on eBay that don't get what you expect. So far the cruising dyneema I have bought there seems to be the right stuff - with proper dyneema core, as far as I can tell (the cover tends to differ by brand)
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I tend to be wary of "cruising" dynema. Surely it is either dynema or it is not dynema
Cruising dynema suggests ( to me anyway) that the dynema core is mixed with polyester threads & that can be just about any mix the manufacturer decides to con the buyer with.
See #50 where a forumite says he can cut the core with a hot knife. Possibly a couple of dynema threads just to suit the sales description & the rest polyester
 
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Rolling downwind on a long passage last week prompted thoughts over replacing my mainsail clew outhaul with dyneema. I had the clew under modest tension to allow some shape in the main however each time the mainsail rolled towards the wind the clew pulled and stretched against the outhaul and the clew slider squeeked as it moved a few mm along the boom.
 
jonjo5 said:
Rolling downwind on a long passage last week prompted thoughts over replacing my mainsail clew outhaul with dyneema. I had the clew under modest tension to allow some shape in the main however each time the mainsail rolled towards the wind the clew pulled and stretched against the outhaul and the clew slider squeeked as it moved a few mm along the boom.
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But if it's like mine it's mostly wire and the rope tail only goes to the mast so maybe too short to be a massive stretch issue; however I'd agree the reason for choosing a dyneema halyard would apply equally to the outhaul and reefing lines, and cunningham if you've got one (I haven't)
 
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