Dyneema / Synthetic Rigging Summary

I have written a lot on rigging your boat with Dyneema and thought it was about time I provided a overall guide to what I’ve written. So I’m going to try to give a coherent guide to what we have explored so far.

First, the obvious question: Why Dyneema standing rigging?, that is more thought through in relation to specific challenges on our boat, than our first mention back in October 2019 was. That was less than 2 months after buying Vida and I mentioned Dyneema standing rigging as a longer term possibility in Starting to sort out sailing. Of course Covid has changed our perceptions of time in a far too many ways. We also explored the progress on sustainable dyneema.

Latest Situation:

Chainplates: Final Dyneema Chainplate design
Attaching Dyneema Shrouds to mast: Currently planning diy tangs made from FR4 board which is an update to dyneema termination and chainplate update the shroud will have an eye splice which will loop over the tang.
Tensioning Shrouds: We are now planning to use a 6mm dyneema lashing between a Low Friction Ring at the bottom the shroud and the low friction ring at the top of the chainstay. We can use the same line for our guardrails.
Dyneema Rigging size: We have just ordered a 100 Metre Reel of 9mm DynIce Dux to replace the 6mm stainless (sizing up for caution)
Sail Plan: We have decided what we are aiming for and how to get there, see long-term desired sail plan

Our Chainplate journey

[Update] after visiting Vida for the first time in 6 months we have a Final Dyneema Chainplate design [end update]

The main learning since those early days been about the problems we face with our chainplates. That continues to evolve (so in my posts be aware that when I write “we plan” those plans may have changed more than once since. Even in the last few days we have learnt of a Rival 38 who had a chainplate (similar to ours except in stainless steel so presumably a replacement set from the original bronze we have) fail during a recent Atlantic crossing. So as we explored these issues I’ve written:

My thinking on chainplates was also affected by thinking about attaching a Jordan Series Drogue in a new simpler way. That reflects my dislike of custom stainless steel solutions. There are the corrosion issues (stainless steel corrodes in the absence of Oxygen – such as where a bolt is sealed as it goes through a deck or hull, and potential electrolytic pitfalls with dissimilar metals). They require someone to build them for you (not always possible in remote places and never free [or even cheap] or immediate). They can have problems that do not show up even with a careful visual inspection.

[Update we have a better idea of like for like replacement see Chainplate cost update.]

An updated design now completed see Next generation Dyneema Chainplates.

That has brought me to a new idea for Simpler Dyneema Chainplates. I have even produced a sketch (you can see why my Dad realised when I was very young that I would not follow him into architecture):

As I think about this solution, I realise that it can probably be adapted for most situations with chainplates that are close to the outside edge of the deck. Our bulwark should allow the holes to be drilled between the two sheets of G10, without coming through to the inside of the boat. However, if there is no bulwark the holes could be drilled and then the inside corner of the hull/deck joint could have a large fillet of thickened epoxy and the hole re-drilled through that.

My previous idea should still work where the holes can’t go external as it allows you to waterproof the dyneema loop below the deck.

Using G10 (above decks) or FR4 (below decks as fire resistant) that is bonded to the hull/deck should distribute loads much more effectively than a typical stainless steel chainplate without any corrosion/electrolytic risks.

Updated design now completed see Next generation Dyneema Chainplates.

[Update] after visiting Vida for the first time in 6 months we have a Final Dyneema Chainplate design [end update]

Attaching Dyneema

Another big issue is what ends you fit on a dyneema shroud. I first wrote about that in Termination of Dyneema Shrouds. The most contentious issue? I stand by my conclusion, that if you can afford it then Colligo Marine have the widest range.

For us, I realised that our masts make it relatively simple for us to make and fit our own DIY/budget version of a Colligo Cheeky Tang for a fraction of the cost see Dyneema Termination and Chainplate update. Also our latest chainplate idea and conversations with Rigging Doctor mean that we will at least start with Low Friction Rings (sized generously) for both the chainplates and the low ends of the shrouds.

Using HDPE: learning from Free Range Sailing again we are looking at using HDPE to create our tangs for connecting the shrouds to the mast and for reducing friction/chafe on the chainplate connections. We are now looking at recycling and creating these components ourselves: see Transforming waste with DIY Plastic recycling.

I’ve added a post “Chainplate and Mast Tang feedback” to answer some really helpful comments from Jacob.

Sizing Dyneema

This is another area that has taken a lot of research and thinking. So I wrote a long post in The mysteries of sizing Dyneema standing rigging.

Sail plan and stays

In Dyneema forestays and backstays I sorted out Dyneema for all the mizzen shrouds and stays. Also for the main mast backstays and inner forestay.

The forestay for the main mast will need to remain stainless steel due to our use of a roller reefing genoa. Possibly in the very long term a roller reefing system might be developed that works with a dyneema forestay.

Another option (which is what I understand the Vendee Globe yachts do) is to move from a single genoa that is roller reefed to having multiple genoas/jibs that can be furled. So when the wind speed increases you furl (roll up) your current genoa, lower it to the deck and hoist another smaller job in a furled state.

With enough halyards you can hoist the new sail (and potentially even unfurl it) before furling and lowering your original sail. The headstay that the sail furls around can be dyneema and it can be structural (ie it holds the mast up and you leave the sail up while it is furled). Or you could have a forestay in front of the sail that is used to hold the mast up. I’m not sure how tensioning these works. Presumably you don’t have the forestay so tight and you put a lot of tension in the sails headstay.

It would also be lovely to fit a small, retracting bowsprit to be able to hoist larger sails such as a code zero (for going upwind in light breezes) or an asymmetric spinnaker (for downwind sailing) out in front of the forestay.

However, all these are expensive options. So we will hope to maintain the existing roller reefing setup for a long time with the inner forestay mainly use for the storm jib if needed. These options also require a lot more working on the foredeck which definitely has it’s disadvantages to offset against better performance and reducing the number of single points of failure.

[Update] See our new post on our long-term desired sail plan and how we intend to get there.[End Update]

Where to start?

We don’t think it is a good idea for your first dyneema splices to be for the shrouds that hold your mast up. Instead both dyneema lifelines and soft shackles seem like much more sensible places to learn to splice dyneema. Billy and Sierra did a good video on this.

We have some ideas about our lifelines to solve potential leaks, some problems with bent stanchions and even to make mounting our tiltable, removable, side solar panels easier. More on that in the future.

15 thoughts on “Dyneema / Synthetic Rigging Summary

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