Low-Stretch Halyards actually worth it for cruising?

[PaulDaniel]

For those of you who have switched between polyester and dyneema halyards on the same boat, what kind of performance increase/decrease did you see (measured in % of speed or boat speed in knots at a certain windspeed)? I just replaced my halyards recently and spent a bunch of money on dyneema halyards. I'm considering perhaps just getting polyester halyards next time. But I'd love to hear feedback from those who have tried both (preferably on the same boat).

And some sail-theory:
The elasticity difference between polyester and dyneema seems to come into play when sailing upwind and the sail is dynamically loaded (gusts). If the loads were completely static, there would not be a benefit from low stretch lines. And it matter mores when sailing upwind because of how halyard tension affects draft. To the extent you would want halyard tension to change in a puff, you would probably want to increase halyard tension in order to maintain draft amount and position. A stretchy halyard does the opposite, potentially causing the draft to increase, move aft, and increase heel. But how pronounced is this effect? It seems like low stretch halyard is an expensive solution to a niche problem.

 

[PaulDaniel]

And to put the price into perspective: I spent $500 on 8mm Marlow D2 SK78 Racing halyards for my Catalina 270. Polyester halyards would have been $125. Those prices include tax. So the cost of going with dyneema over polyester was $375 (or $187.50 per sail). So not the end of the world. But that's almost $400. I would say the boat and trailer together are worth around $25k. The cost of maintenance and wetslip might be $2.5k per year (I have a good deal on the wetslip). If you capitalize that annual expense to a present value expense at 10% annual return, it would be a $25k present value expense. So that is a total present value expense of $50k. A $375 halyard upgrade is about 0.75% of that. So you could ask the question, "Does dyneema halyards represent a 0.75% or greater increase in joy of boat ownership?".

 

[BarryL]

Hello,

I don't think you'll be able to gather any data regarding performance improvements, the difference is probably too small to accurately measure.

A few thoughts from me
Halyards should last a long time, like 10+ years
How are your sails? If you have older dacron sails, low stretch halyards are a waste of money because the sail will stretch during a gust.
As you wrote, the only time the low stretch line makes a difference is when the wind is puffy / gusty. Assuming good quality low stretch sails and low stretch halyards when the gust hits, the boat should accelerate. With dacron sails and polyester halyards when a gust hits the draft increases and moves aft and the boat will heel more and accelerate less. When racing this is super important. When cruising it's not that important.

Good luck,
Barry

 

[colemj]

And to put the price into perspective: I spent $500 on 8mm Marlow D2 SK78 Racing halyards for my Catalina 270. Polyester halyards would have been $125.

That cost difference is likely only because you needed a certain size dyneema line to fit existing clutches, or at least be comfortable to handle.

Otherwise, there is almost no price difference between high modulus and dacron double braid lines when bought based on working load. Marlow's D2 Racing is a top-of-the-line rope. Here is a lower level 8mm dyneema core rope for $1.20/ft that will out-perform any polyester double braid and likely be cheaper to boot: Departments - NEW ENGLAND ROPES VIPER LINE HANKS

The other benefit dyneema lines have is that none of the strength is carried by the cover, and the dyneema core is highly chafe resistant. Polyester double braid carries half of its strength in the cover, and both cover and core are susceptible to chafing - setting up a failure spiral.

The reasons to go dyneema over polyester for halyards go beyond just sail shape. With the caveat that dyneema needs to fit clutches or be able to be handled, there isn't any reason or advantage at all to use polyester double braid for any line on a boat.

Mark

 

[PaulK]

BarryL has hit nail on the head. On your boat Dyneema halyards might increase your speed by .00003 seconds per mile in flat seas and 10 Knots of wind using new North 3Di carbon sails. You will be able to apply this to every race over the next ten or more years until the Dyneema needs to be replaced. The time to ask this question was before you bought and installed the new halyards, not after. On the other hand, competitors seeing that you just added Dyneema halyards might decide to be less aggressive than before, seeing that you're obviously focused on improving your performance, so you might beat them more often. What's that worth?

 

[PaulDaniel]

Thanks for the responses. My sails are in “fair”condition. I’m not sure exactly how old they are. I think the jib was probably bought when the new mast and furler were installed 13 years ago. The main is in similar shape. The boat did come with laminated racing sails but I never use them.

It seems like if Dyneema halyards are deemed appropriate, and you are using polyester sails, then the sails at least should have a Dyneema luff. Having a very rigid halyard and very stretchy luff seems odd.