Do insurance companies accept Dyneema standing rigging?

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BurnitBlue

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Thinking of changing over to Dyneema Standing Rigging from usual Stainless. Do insurance companies accept this material or do they load the premium? Thanks
 
BurnitBlue said:
Thinking of changing over to Dyneema Standing Rigging from usual Stainless. Do insurance companies accept this material or do they load the premium? Thanks
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With all things insurance write to them and ask, get a reply in writing. Anything can be insured; at a cost.
 
As a general rule if it's something standard and fitted by a professional then they would accept it, but as Sandy says ask them the question specifically.

If you fit your own dyneema rigging to save money then the answer would likely be different, and they may not ask who fitted it until the mast is in the water and you're making a claim, so be specific in your question.
 
Weĺl, those answers make sence, thank you. Swedish boat show early next year.where most venders have a presense. I will be aware of the danger of making deals not in writing.
 
BurnitBlue said:
Thinking of changing over to Dyneema Standing Rigging from usual Stainless. Do insurance companies accept this material or do they load the premium? Thanks
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Out of interest ……. Why?

S/s wire works for most cruising yachts, is well proven and reliable. Unless doing serious racing, and in class rules, why fix stuff that ain’t broken?
 
dunedin said:
Out of interest ……. Why?

S/s wire works for most cruising yachts, is well proven and reliable. Unless doing serious racing, and in class rules, why fix stuff that ain’t broken?
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From the web -

Changing rigging from stainless steel to Dyneema on a cruising boat offers several benefits and some potential downsides. Let's explore both aspects:

Benefits of Dyneema Rigging​

Weight Reduction
Dyneema rigging is significantly lighter than stainless steel, which can have a dramatic effect on your boat's performance. This weight reduction:
  • Decreases heeling, making sailing more comfortable
  • Improves speed and overall performance
  • Reduces the need for ballast, potentially saving up to 1,000 kg on an 80-foot yacht
    3
Strength
Dyneema is incredibly strong for its weight. When sized correctly, it can be:
  • 2 to 5 times stronger than the steel wire or rod it replaces
  • Up to 5 times the tensile strength of regular polyester rigging
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DIY-Friendly
One of the most significant advantages for cruisers is the ability to work with Dyneema yourself. This means:
  • Easy installation and maintenance
  • Ability to carry spare materials for repairs anywhere in the world
  • No need for specialized tools or components
    4
Corrosion Resistance
Unlike stainless steel, Dyneema doesn't corrode, eliminating a common failure point in traditional rigging
2
.Flexibility and Handling

Dyneema is more flexible and easier to handle than stainless steel, making it easier to work with during installation and adjustments
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Downsides of Dyneema Rigging​

Stretch and Creep
Dyneema is more elastic than stainless steel and suffers from creep (permanent elongation under constant load). This means:
  • More frequent adjustments are necessary
  • It requires "active management" of rig tension
  • Not suitable for applications where repeatable rig tune settings are critical
    3
UV Degradation
While Dyneema has some UV resistance, it is more susceptible to UV damage than stainless steel. This requires:
  • Regular inspections
  • Potential need for UV protective coatings or covers
    1
Chafe Sensitivity
Dyneema doesn't handle chafe as well as stainless steel. This leads to:
  • Need for chafe guards in high-wear areas
  • More frequent inspections and potential replacements
    1
Initial Cost
While potentially more cost-effective in the long run, the initial cost of Dyneema rigging can be higher than stainless steel
4
.Unfamiliarity

As a relatively new technology in cruising applications, some sailors and marine professionals may be unfamiliar with Dyneema rigging, potentially leading to challenges in getting work done or inspections in remote locations.In conclusion, while Dyneema offers significant advantages in terms of weight, strength, and ease of handling, it requires more active management and regular inspection than traditional stainless steel rigging. For cruising sailors willing to take on this additional responsibility, the benefits can be substantial, particularly in terms of performance and self-sufficiency.

The Pros and Cons of Dyneema vs Stainless Rigging
Boat Rigging: A Comprehensive Guide to Ensure Smooth Sailing
Standing Rigging - why you should change to composite rigging
Why Dyneema standing rigging?
https://www.svb24.com/en/guide/all-about-dyneema-rigging.html
The Essential Guide to Dyneema® Loops for Sailing - blog

All or nothing in some respects though--

Dyneema reacts differently to temperature changes compared to stainless steel, which can indeed make a rig mixing both materials problematic. This difference is due to their contrasting thermal expansion properties:

Thermal Expansion Characteristics​

Dyneema
  • Has a negative coefficient of thermal expansion: -12 x 10^-6 per Kelvin (or per °C)
  • Contracts as it heats up and expands as it cools down
Stainless Steel
  • Has a positive coefficient of thermal expansion: typically around 17 x 10^-6 per Kelvin (or per °C)
  • Expands as it heats up and contracts as it cools down

Implications for Rigging​

The opposite reactions to temperature changes can lead to significant issues in a mixed rigging setup:
  1. Tension Variations: As temperature increases, Dyneema rigging will contract while stainless steel expands. This leads to uneven tension distribution across the rig
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  2. Tuning Challenges: The rig's tune will change dramatically with temperature fluctuations, making it difficult to maintain proper tension throughout different weather conditions
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  3. Potential Damage: If the rigging is tuned on a cold day, it may become dangerously tight in warmer weather, potentially causing damage to chainplates, tangs, or other components
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Magnitude of Change​

The difference in length changes can be substantial:
  • For a 20-meter length of rigging and a temperature change of 40°C:
    • Dyneema would contract by about 9.12 mm
    • Stainless steel would expand by about 13.6 mm
This results in a total difference of nearly 23 mm (almost an inch) between the two materials
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Considerations for Mixed Rigging​

If using a mixed rigging setup:
  1. Careful Tuning: Always tune the rigging on a warm day to prevent over-tightening in higher temperatures
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  2. Regular Adjustments: Be prepared to adjust rigging tension more frequently to account for temperature changes.
  3. Material Pairing: Consider using Dyneema rigging with carbon fiber spars, as they have more compatible thermal expansion properties
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In conclusion, while both Dyneema and stainless steel have their advantages in rigging, their different reactions to temperature changes make mixing them in a single rig challenging and potentially problematic. Careful consideration and management are necessary if such a mixed setup is used
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flaming said:
Yes....

But it's significantly more challenging to splice accurately to an exact length. Just getting my double inhauler system to balance took a lot of trial and error.
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Not really an issue for standing rigging since the exact length of the stay is irrelevant as long as it's a bit short of where it attaches. The tension is added afterwards, same as with stainless.
 
flaming said:
Yes....

But it's significantly more challenging to splice accurately to an exact length. Just getting my double inhauler system to balance took a lot of trial and error.
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though you only need to do that once, spend a few hours logging how much a splice reduces the length then next time you can get pretty accurate so the turnbuckles are near the centre of their travel.

Another trick for wanting a length which might change is have a big long tail which exits the working part at the end of the bury, but with no modified brummel.
 
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lustyd said:
Not really an issue for standing rigging since the exact length of the stay is irrelevant as long as it's a bit short of where it attaches. The tension is added afterwards, same as with stainless.
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Hmmmm. I'm not totally convinced, you'd want the stays to be as accurate as possible so you don't have wildly mis-matched bottlescrews.

And although I do a fair bit of splicing on various bits of running rigging, when it came to splicing the cascade for my backstay, I decided to let the rigger do it. He splices every day, I don't. I figure his hourly rate is quite reasonable in terms of peace of mind and access to his professional insurance should it fail....
 
Weight reduction and strength are not benefits on a cruising yacht. You would choose a diameter to match your required strength so it’s irrelevant. Choose stronger and you are asking something else to break first.
 
lustyd said:
The entire purpose of bottlescrews (which aren't used on Dyneema rigging) is to allow for mismatched length stays. You may have OCD :)
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Well no. The purpose of bottlescrews is to tune the rigging, allowing you control over the shape of the mast. What you definitely do not want is one side to be almost all the way wound down, and one side to be almost all the way unwound for the same tension.

I guess the point is, yes Dynema is easy to splice. Yes it can work as a rigging material. However, if you're looking for a cost saving and this is your first go at it, you probably need to factor in needing to re-do at least 1 stay, probably more.

If you're looking at a weight saving, and performance benefits and hang the cost, then the composite rigging solutions are probably a better bet.

If you're looking for ultimate "user serviceability" in remote places, and especially on a boat with a simple rig, then sure Dynema can have a place. There are however issues with creep and the fact that compared to the mast it's thermal properties are inverse. Dynema shrinks with heat, where metal expands. So if you rigged a boat in an English winter, then sailed South in the summer your mast will get a bit longer, but your stays shorter...
People who have changed report that it is not "set and forget" as most cruisers like to treat their rigging.
 
flaming said:
The purpose of bottlescrews is to tune the rigging, allowing you control over the shape of the mast
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Most Dyneema rigs don't use bottlescrews for this, tension is added with some cord. I think you're overstating the importance of rig tuning for most folk, even in racing it's more a fetish than a requirement. Traditionally, "rig tuning" consisted of sailing a broad reach and tightening the leeward side until it wasn't loose, then turning 180 and doing the same.
 
lustyd said:
Most Dyneema rigs don't use bottlescrews for this, tension is added with some cord. I think you're overstating the importance of rig tuning for most folk, even in racing it's more a fetish than a requirement. Traditionally, "rig tuning" consisted of sailing a broad reach and tightening the leeward side until it wasn't loose, then turning 180 and doing the same.
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The point is that Dynema, awesome as it is, does creep. So when used as rigging if you did that same trick, a month later you leeward rigging would be loose and you'd need to do it again. So if you don't like tuning rigging (and I 100% agree with you on the typical relationship between a cruising sailor and rig tuning) then you'd still find yourself needing to do it.

And if it's not a bottlescrew... Then it's more complicated. For example....

 
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