Difference Dyneema versus Polyester Halyard in real life

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zeeotter

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I sail an average 100% cruising center cockpit of 36 feet. The genoa and mainsail halyard need to be replaced. The choice is between a regular pre stretched polyester line and a dyneema one. I know all about the difference of stretch between the two different materials in theory. But what difference can I expect between 12 mm polyester or 10 mm dyneema halyard in real life. Is the difference notable in the shape of the sails? Have anybody practical experience with this?
 
You will notice the difference with Dyneema, Spectra etc .

For me, Dyneema halyards don't need nearly so much adjustment because they stretch so little.

The racing boys swear that when you get a puff you don't loose any power, again due to the lack of stretch.

I have bought mine selectively from the net and boat jumbles meaning that I pay about the same as for polyester. I would always have an outer cover.
 
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Try tying equal lengths of dyneema and polyester braid to a fixed object such as a lamppost or large tree. Even with lengths as short as 12-15m the difference in stretch is remarkable.
 
duncan99210 said:
Real life, 100% cruising, you'll not notice the difference, except to your wallet.
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I'm not sure I agree with that. Length of halyard likely to be about 15m (once the sail is hoisted). Prestretched polyester might stretch 2% giving 30cm of stretch. Decent dyneema will stretch less than 0.5%, resulting in 7.5cm of stretch. Even when cruising, you want your sails to be as flat as possible when you're in a blow.
 
You'll save a lot of money in the long run if you buy your new halyards 10' longer than necessary. Then every year or two cut off the shackle end by 1' and move the shackle up to the new position. Don't bother with splicing the shackle to the end of the halyard; just tie it on. This will move all of the wear points on the halyard, so the whole thing will last for years and years. You won't mind the extra cost of Spectra if it is spread over 10 years.

This conversation is timely because I'm going down to my boat tomorrow afternoon to move all of my shackles up in this manner. It saves a ton of money.

In answer to your original question, you will notice if you are worried about that kind of thing. You won't notice if you aren't.
But now that you've brought it up, every time you leave the dock you'll be watching your sail slip down. Gets really frustrating.
 
I've never had noticeable halyard stretch, ever. My criterion with ropes on my boat is ease of handling. I'd rather have a 14mm rope in my hand than a 10, 12 mm than an 8. Dynema is a wonderful material but overkill for small yachts. It might make a difference on a big ocean racer, I suppose and there are always those who want the latest kit. If I were so concerned about sail shape, I'd rather spend the money on better sailcloth.
 
GrahamM376 said:
Before we changed the halyard the mainsail used to slacken off and it wasn't clutch slip. 12mm poly changed for 12mm dyneema and no longer have to re-tension it.
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My experience also as a non-racer. No more irritating luff flutter. Definitely go for dyneema or the likes.
 
Foolish Muse said:
You'll save a lot of money in the long run if you buy your new halyards 10' longer than necessary. Then every year or two cut off the shackle end by 1' and move the shackle up to the new position. Don't bother with splicing the shackle to the end of the halyard; just tie it on. This will move all of the wear points on the halyard, so the whole thing will last for years and years. You won't mind the extra cost of Spectra if it is spread over 10 years.

This conversation is timely because I'm going down to my boat tomorrow afternoon to move all of my shackles up in this manner. It saves a ton of money.

You'll save a lot of money in the long run if you buy your new halyards 10' longer than necessary. Then every year or two cut off the shackle end by 1' and move the shackle up to the new position. Don't bother with splicing the shackle to the end of the halyard; just tie it on. This will move all of the wear points on the halyard, so the whole thing will last for years and years.

Could you further extend the life by swopping the rope end for end? Or would that just be too much hassle?
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Foolish Muse said:
You'll save a lot of money in the long run if you buy your new halyards 10' longer than necessary. Then every year or two cut off the shackle end by 1' and move the shackle up to the new position. Don't bother with splicing the shackle to the end of the halyard; just tie it on. This will move all of the wear points on the halyard, so the whole thing will last for years and years. You won't mind the extra cost of Spectra if it is spread over 10 years.

This conversation is timely because I'm going down to my boat tomorrow afternoon to move all of my shackles up in this manner. It saves a ton of money.

In answer to your original question, you will notice if you are worried about that kind of thing. You won't notice if you aren't.
But now that you've brought it up, every time you leave the dock you'll be watching your sail slip down. Gets really frustrating.
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Can anyone comment on tying knots in Dyneema? I thought it was something to be avoided due to loss of strength.
I'm currently using wire hayards with rope tails but these will need replacing soon.
 
DanTribe said:
Can anyone comment on tying knots in Dyneema? I thought it was something to be avoided due to loss of strength.
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Not really an issue with dyneema, a knot will loose maybe 50% of strength in any rope, you won't break dyneema. What can happen in unsheathed dyneema is it will slowly slip through the knot as it is so slippy though there are it's which get round this.
 
zeeotter said:
I sail an average 100% cruising center cockpit of 36 feet. The genoa and mainsail halyard need to be replaced. The choice is between a regular pre stretched polyester line and a dyneema one. I know all about the difference of stretch between the two different materials in theory. But what difference can I expect between 12 mm polyester or 10 mm dyneema halyard in real life. Is the difference notable in the shape of the sails? Have anybody practical experience with this?
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Yes, I always use inexpensive polyester braid.

It's no problem to me in general cruising, and you won't find the main getting very baggy in benign conditions partly because of the friction in the system. A bigger inconvenience is the increased free length, and reduced luff friction, exposed when deeply reefed, when you may struggle to keep the sail flat in the conditions.

The genoa will start to crease at the top end of it's range but this tends to become irrelevant as you reef.

In my view it is another analogue question for which people seek digital answers. In fact I will probably use this staggering bon mot at the foot of my posts.
 
I use dyneema halyards, sheets and reefing pennants and have done so for 20 years or more, so I'm obviously convinced it makes a difference.

Whether it makes a difference to the OP depends on how you sail, if you have a yacht which doesn't sail to windwards well and you tend to motor when you could sail closed hauled and tack, then it won't make any difference. It won't make an appreciable difference when your reaching or running.

But, if you enjoy the challenge of sailing well to windward, then you'll immediately notice the difference. The luff of the sail will stay tight and the sails won't go baggy when you sheet everything in to sail hard on the wind in 10 to 12 knots true wind. The difference will become even more apparent when you reef, you'll be able to flatten the reefed sail and it'll stay flat as the wind increases.

My observations of yachts on the West Coast of Scotland over many years is that at least 50% put the diesel on when faced with an upwind passage. This is particularly true of the Sound of Mull, where most motor up wind. For those who prefer to motor upwind, go for polyester and save you money to buy diesel !
 
I have used both dyneema and polyester, for cruising I would go for polyester, much nicer to handle and less prone to slip in clutches. When used for halyards the tension will soon remove the tendency to stretch elastically so that after a few weeks use the tension marks on the rope at the clutch no longer need to be changed. My gennaker halyard is old well used polyester braid and it has lost all its stretch and softness as it was previously used for a genny. A better arrangement would have been to use it as a spinnaker halyard first while it was more stretchy and shock absorbing but with the price of rope these days????
So on the Finngulf, the genny is wire composite, so easy to read the tension on the luff for different conditions, there are only two headsails and we rarely need to switch to the blade so not handled much other than to adjust luff tension. The main halyard which is handled every day, the genny car traveller lines and the backstay tackle are all dyneema, the main has to be watched for creep in the clutch when under high tension. And the gennaker (we dont have a spinnaker any more) is polyester.
 
Most problems with halyards slacking is caused by clutches slipping. Dyneema is better but the owner/skipper will need to be at least half interested in performance sailing to make it worthwhile.
 
RobF said:
I'm not sure I agree with that. Length of halyard likely to be about 15m (once the sail is hoisted). Prestretched polyester might stretch 2% giving 30cm of stretch. Decent dyneema will stretch less than 0.5%, resulting in 7.5cm of stretch. Even when cruising, you want your sails to be as flat as possible when you're in a blow.
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I don't disagree, but most of that stretch comes when you first tension up the line. What matters is if there is any further "creep" stretch once initially tensioned and cleated/jammed.

Dyneema is undoubtedly superior, but for cruising (even for me, who likes sails to set well), polyester is OK and generally easier to handle and live with. As others have said, have halliards a bit overlength and turn or trim them shorter occasionally to move wear/friction points. Polyester you can use "selden knots" instead of eye splices: in slippy dyneema I wouldn't trust them.
 
I would recommend cruising dyneema for ... well as the name suggests, cruising. Much cheaper than full on racing dyneema and often a more gentle cover. Bought three lots so far from a UK supplier via eBay.

Certainly avoiding halyard stretch is important for cruising. The sail shape, specifically how far back the maximum depth of sail goes, is critically important for sailing to windward, particularly in a blow. The halyard tension is critical for this. And pointing higher and going faster means any windward work is finished faster - hence more comfortable when cruising (unless you are the type who only motor upwind, in which case knicker elastic will do)
 
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