More on sustainability

I get quite frustrated with a number of ways in which claims are made for sustainability. Too often they can be most charitably be described as greenwashing.

So I took the Footprint challenge (again) at

This time we came out at 2.3 that means 2.3 worlds would be required to maintain our lifestyle. It can also be presented as 3.9gha (global hectares per person). The world can sustain about 1.63gha, the UK average is 7.93gha and the global average is 2.75gha.

So while we are currently living at about 50% of the UK average (2016 data) and just below the global average (again 2016) we still have a long way to drop before we could consider ourselves to be living sustainably.

This is a reduction from what we have achieved in the past. However, by far the largest single item within our footprint is our housing. As that comes with my job we have almost no control over it, at the moment. The second (although only about 1/3 of the first) is driving our van. This calculator doesn’t factor in the cycling I do for transport and of course we are working towards replacing the van with a small electric car ASAP (that reflects changes including Jane commuting for the first time).

Factors that have reduced our score include:

  • No flying (more than 15 years since our last flight)
  • All our Electricity and Gas is the greenest, most renewable available (Ecotricity)
  • We are now nearly completely vegetarian
  • Most of our veg comes through a weekly veg box from a farm only 15 miles away (and everything in the box is grown organically on that farm).

However, Sustainable Sailing is about our long term, our retirement. At the point of retirement we have to find our own home (and we can’t afford to buy a house) and we want to be contributing to life not tearing it down for future generations.

So our goals are a retirement we can afford (which is why the catamarans costing hundreds of thousands of pounds are irrelevant) and which has a really low footprint (which is again why the big catamarans are out as well as diesel engines, new boats etc).

But we also believe that there are mental and physical benefits to a simpler and more sustainable life. So the choices are also good for us personally. Less stress, more beauty, more experiences, active lifestyle away from air pollution.

So it isn’t surprising that the people we prefer to read or watch are typically not the lifestyle experts, they typically have old boats and low budgets.

It isn’t surprising that we reject the experts saying that fossil fuel free sailing boats are not possible because we have not seen them consider the footprint of their choices. Our goal isn’t to achieve or maintain a lifestyle that the planet can’t sustain. Our goal is to to live at a sustainable level, and within that, to live well.

A good recent example was that Jimmy Cornell who has had to abandon his attempt to sail around the world with zero carbon emissions. Our approach is very different.

When they start with a brand new 45 foot catamaran the embedded carbon footprint is incredibly different to that of a 43 year old 38 foot monohull and this is almost always ignored.

The key advantages of a performance catamaran for cruising without using fossil fuels are the large area for solar panels and the higher sailing speed which means that regeneration from spinning the propellers which turn the motors into generators.

However, we plan about the same amount of solar panels, and we plan to boost their efficiency by tilting them and moving some so that are not shaded by the sails as much.

We too hope to get some regeneration from the propeller but haven’t really budgeted for it.

Where the biggest difference lies is in consumption. That is where the expectations of sustainability are so different. We plan to live within what we can generate not generate enough for a particular lifestyle.

Within the consumption side of the equation comes a really significant disadvantage of catamarans. They can’t be steered by wind vane steering systems that use no electricity. We have seen a number of people whose boats use electric autopilots have to run their engines every couple of days because of the power drain of the autopilot. While we are going to maintain the original electric autopilot (useful for sail changes or when motoring) we won’t be using it on passages.

When you add electric winches, multiple fridges etc it becomes obvious that it is the luxury lifestyle that can’t be achieved. Yet for hundreds of years sailing boats have crossed oceans without fridges, washing machines, water makers etc. Even on a catamaran with it’s autopilot Cornell managed on a “minimal” use of electrical equipment.

Yet the naysayers always home in on the induction cooking and the electric motor as the problems that make zero carbon footprint sailing impossible. Neither of these need to be used if you don’t have enough power in the battery bank. Especially when crossing oceans.

For us the two biggest concerns (and the reason why, in the end we may well carry a generator) are:

  • Fossil fuel free heating (because electric heating is always going to be needed most when solar generation is at it’s minimum).
  • Canals and rivers (eg to get between the English Channel and the Mediterranean) where hours of motoring can be needed against currents or where timetables need to be kept (eg Panama Canal).

To be honest it is amusing that those telling us that a sustainable life isn’t possible haven’t even thought about the most difficult challenges.

It is important to note that we don’t think we have everything sorted yet. We are building up gradually on storage, generation and consumption of electricity so that we can find a good equilibrium for us – and yes, that will include restricting where we go to those places and seasons where we can maintain the equilibrium because anything else isn’t sustainable.

The urge to be the first

Saw some exciting news today.

Just read that Peter Lawless is going to be sailing his Rival 41 around the world single handed, unassisted and non stop. He has a website and a YouTube channel. His aim is to be the first Irish man to achieve that combination.

It is nice to see such confidence in the next size up boat in the Rival range 😁 While we know several Rival 38s have circumnavigated, I’m pretty confident none have done so non stop, and probably not routing south of all 5 major capes.

If you haven’t looked at sailing routes in detail it might surprise you that there is a fundamental difference in the routes between those sailing around the world fast and cruising.

Typically fast circumnavigations are Eastwards (so from Europe via Africa, Australia, Americas to Europe) and they go a long way south to keep the distance down (typically circling Antarctica as close as possible). This is the route of the Vendee Globe, the Jules Verne trophy etc. It goes under 5 major capes: Cape of Good Hope (South Africa), Cape Leeuwin (Australia), South East Cape (Tasmania), South Cape (New Zealand), Cape Horn (Chile) There are normally a series of low pressure systems circling the globe above Antarctica so Eastwards is faster downwind sailing.

For cruisers that Southern Ocean is unattractive, if the objective is to enjoy visiting places then a route to the most remote parts of the oceans where storms are normal and it is very cold is unattractive. Cape Horn is particularly feared as there is a pinch point between it and Antarctica where winds and seas rush through. So the majority route Westwards using the Panama Canal to avoid Cape Horn. Then you can cross the Pacific via some of the beautiful island groups in warmer weather with downwind sailing to Australia. If piracy wasn’t an issue many would return to Europe via the Red Sea, Suez Canal and Mediterranean thus avoiding the more challenging Cape of Good Hope.

So there is this huge difference right from the beginning depending on whether you want to go around non stop (or just a few stops) or whether you want to see more places, go slower and take fewer risks.

We are definitely in the cruising camp (and with a grp boat relying on solar energy we won’t be going to far North or South into the Arctic or Antarctic). But it made me wonder if we have any urges or expectations to be first at anything. We certainly are not considering single handed firsts, nor a non stop circumnavigation, nor do we aim to be unassisted.

On the other hand wherever we go we will be the first Jane and Dave to sail a Rival 38 Centre Cockpit Ketch there 😂

Is that enough?

For us it definitely is. We love watching and supporting others doing amazing things (like the Vendee Globe) but that isn’t us.

Instead, our goals are clearly much more about the means (ie Sustainable) rather than specific firsts. To travel well (by our definitions) rather than to set records.

Boat access update

So we were last on Vida for Friday 9th October (Friday Progress 28). Since then the restrictions either for North Wales or for Manchester (and for a lot of the time both) have not allowed us back.

We had hoped to get a few days after Christmas but Manchester is still in tier 3 and Wales goes into a pretty full lockdown from the 28th December.

With very little prospect of change for a couple of months it does mean we will need to plan carefully whether to try to get enough done to launch in 2021 and finish over next winter or see if we can get a more complete refit complete for 2022.

I have a 3 month sabbatical in 2022, we would love to use that for our first extended cruise but we would need to have completed so much and tested it beforehand.

Feeling more than a bit frustrated by the knowledge that going and working on our boat is incredibly low Covid risk. We don’t stop on the way. We typically don’t meet anyone. The only shopping we do is for electricity cards from the boatyard chandler.

Yet the rules are clear and we are not about to break them. We have seen too much of the devastation that Covid causes.

The mysteries of sizing Dyneema standing rigging

When planning Dyneema rigging the area we have found most confusing is deciding on the size of Dyneema we should fit. In our search we have found three sites particularly helpful. However, between the sites we have found at least four ways of deciding what size is needed. Despite that, they do all agree that Dyneema needed to be sized for Stretch rather than for Strength. That is because a Dyneema line the same strength as the Stainless Steel it replaces would be too stretchy to work.

Stretchy is slightly problematic because there are multiple forms and the terminology used isn’t consistent. From Marlow Ropes we have this:

  • Initial loading will result in elastic extension. This is immediate upon loading and is immediately recoverable upon release of the load (elastic contraction)
  • After the elastic extension of the initial loading, the rope will experience what is known as viscoelastic extension. This is further extension over time and is fairly limited. Unlike elastic stretch, viscoelastic stretch will only recover slowly over time once the load is released.
  • Finally there is creep, which is permanent, non-recoverable and time dependent. Creep occurs at the yarn molecular level when the rope is under constant load.
  • Once the load is released and elastic and viscoelastic extension recovered, the rope will ultimately have experienced an element of permanent extension. This is a factor of both creep and “bedding in”, which is when individual fibre components in the rope and / or splice settle into their preferred position when under load.

Others refer to Elastic Stretch, Constructional Stretch and Creep. Unfortunately lots of the information isn’t clear about which they are referring to in their guidance.

I’m least concerned about Constructional Stretch or bedding in. Most lines are pre-stretched. If you measure a pre-stretched line before splicing then you can stretch it after and by measuring know if you have removed the constructional stretch. If your design includes lashings (which are normally setup to have plenty of adjustment) then there is only the inconvenience of a tightening a few times initially if you didn’t get rid of all the constructional stretch.

Creep will mean your rig needs re-tensioning over time. This is mostly a problem if you only use turnbuckles due to their limited range. If you have a lashing in the design you can have shorter shrouds and a longer lashing so that you have plenty of space to keep tension as creep lengthens the shroud. It can be minimised by keeping static loads as a small % of the breaking strength, so grades of Dyneema with a higher breaking strengths will creep less under the same load.

Elastic Stretch is much the same to work with as creep except that it will show up quite quickly, so a few re-tensions in the first few months should sort it. Again, increasing the line diameter reduces the problem as does being able to get enough tension to stretch out the elasticity so that the rig doesn’t flop around.

What makes this even more complicated is that a) there are lots of variations of Dyneema available, also b) each rope manufacturer has their own ways of treating Dyneema (eg pre-stretch, heat treatments, and coatings) which makes comparisons even more difficult.

In terms of suitability for us, we have got that down to this list of basic Dyneema variations (we haven’t found a comparison between the different ways of treating the same type of Dyneema):

  • DM20 (least creep, but also not as strong, most expensive)
  • SK99 (Strongest, similar creep to SK78)
  • SK78 (the first Dyneema with reduced creep)

Rigging Doctor describes all these (and others that we are not considering), not much has changed since that was written in 2015 apart from the gradual introduction of Bio-based Dyneema (expected to reach 60% of all Dyneema by 2030) and a reduction in the premium pricing for DM20 and SK99. Also Marlow describes them all and includes comparison charts. I found the Colligo information less helpful, it feels to me that they have stayed with the same materials despite the new developments. As Jimmy Green put it in an email to me “In terms of picking between DM20 and DynIce Dux, the choice comes down to whether you want the better performing fibre (DM20) or the better performing rope once braided and heat stretched (heat stretched SK75). Marlow recommend one thing, Colligo another, they both swear by the logic!
See the first comment below from John Franta, Colligo Marine where he explains the difference between heat stretching at Fibre level (SK78 and SK99) vs at the Braided level (SK75). So I am going to be adding Hampidjan DynIce Dux into my calculations and it is cheaper than the LIROS D-Pro-XTR, plus available in more sizes.
[End Update]

As we go through the sizing calculations comparisons are difficult as they don’t use the same version of Dyneema. So the sites we have used are below and for each I have sized replacements for our Mizzen mast (currently 6mm or 6.5mm Stainless Steel – can’t be sure until we can visit) and our Main mast (currently 8mm we think).

So these are the sites I’ve found most useful in working sizes for our boat.

Colligo Marine

Still the biggest name that we have found producing fittings for Dyneema rigging. Their page (from 2015) Before Ordering Your Colligo Dux Rigging… links to a PDF table for sizing.

From them we get either 7 or 9mm for the Mizzen and 11mm for the main.

Jimmy Green Marine

Our preferred rope supplier, Jimmy Green Marine, has lots of information and a range of Dyneema for standing rigging from different suppliers. They sell 100m drums and 50m hanks which is handy (they can also make custom lengths with a variety of splices etc). They have been very helpful in responding to email enquiries. They make the information from manufacturers such Marlow rather more accessible.

If we follow the table they include from Marlow for their DM20 line (Marlow M-Rig Max) then sizing is huge: 11 or 12mm for the Mizzen and 15mm for the main.

Rigging Doctor

We are Patreons of Rigging Doctor, the combination of their YouTube channel and website has more practical resources on real world cruising use of Dyneema than any other I’ve found. Our preferences are going to be to tune the rig for a bit higher performance and sail a bit harder than they do but it is still be best source of information we have found. Their sizing post is Sizing for Creep. That has two ways of calculating the size.

The first is the RM30 heeling test to calculate rig loads. “RM30 is the force that is required to heel the boat over 30 degrees.” We are ruling this one out for us. a) we need to replace the mizzen rigging before we launch b) there is no dock or anything at the boatyard so difficult to do c) I’m not sure how this would work for a mizzen mast as it is shorter and so far aft, therefore it would be very difficult to heel the boat that far with just the mizzen and not very typical of the mizzen usage.

The second is a calculation based on the current rigging size. We start by calculating the designed tension of the shrouds by assuming it is no more than 20% of the breaking strain of the stainless steel. Then we choose what percentage of the breaking strength of the Dyneema we want this to be. Herb suggests under 15% or even better under 10%. I’ve taken the stainless breaking limits from the Marlow table off Jimmy Green (see above).

For 6mm stainless steel the breaking strength is 2880kg. 20% is 576kg so if we size at the 10% we get 5760kg (we can simplify the calculation to looking for a Dyneema line that is at least twice the breaking limit of the stainless it replaces). Looking at the Jimmy Green table for all the Dyneema they sell we find that 7mm is good (except Liros don’t sell 7mm so it has to be 8mm for the Liros D Pro Xtr [SK99] or 10mm for the Liros D Pro Static [DFM20] ).

For 6.5mm stainless steel the breaking strength is 3220kg. So we are looking at approx 6500kg breaking strain Dyneema. The Dyneema sizes can be the same as for the 6mm Stainless above except that the Marlow M-Rig Max (DM20) might be better in 8mm.

For 8mm stainless steel the breaking strength is 4640kg. So we are looking at approx 9300kg breaking strain Dyneema. The Dyneema sizes can all be 10mm except the Liros D Pro Static [DFM20] which would need to go upto 12mm (no 11mm available).

Our choices

The price difference of the DM20 lines over SK99 or SK78 is still huge. Jimmy Green have 100m drums of 8mm in all 3 types of Dyneema from Marlow:

Marlow Excel D12 Max 78 (SK78) is £1,145
Marlow Excel D12 Max 99 (SK99) is £1,400
Marlow M-Rig Max (DM20) is £1,337

The Liros 8mm ropes are:

LIROS D-Pro-XTR (SK99) is £868
LIROS D-Pro Static (DM20) is £1,140

The Hampidjan (recommended by Colligo) 8mm rope is

DynIce Dux Dyneema SK75 is £800

While I would love to buy Marlow as a British company, they are a lot more expensive.

We were thinking LIROS D-Pro-XTR (SK99) as by far the cheapest option (and as SK99 is stronger than SK78 we should have less creep than the cheapest Marlow option which is SK78). Of course what we have not been able to compare fully is the performance of Marlow vs Liros in heat treatment, pre-stretch and coatings. If I were only using turnbuckles for tensioning then I might have gone for DM20 to avoid running out of tensioning due to creep.

However, DynICE Dux is now back in the running, and with the possibility of 9mm for the Mizzen for about the same price as the 8mm Liros D-Pro-XTR.

But what about the size?

One seemingly easy option is to over-size. As you size up creep and stretch will always be reduced. Plus there will be more spare strength if there is UV or Chafe damage. But the disadvantages are cost (not just the line but also the thimbles) and windage (but we have a big boxy wheelhouse so are not exactly aerodynamic).

Let’s be very conservative and assume we are looking at existing stainless 6.5mm for the mizzen and 8mm for the main (will check as soon as we are allowed to visit the boat). Let’s go up whenever there doubt. So the 3 different calculations give us (for the Liros D-Pro-XTR)

Mizzen 6.5mm Stainless:

Colligo (SK75): 7mm
Marlow from Jimmy Green (DM20): 12mm
Rigging Doctor for SK99: 8mm

Main 8mm Stainless:

Colligo (SK75): 11mm
Marlow from Jimmy Green (DM20): 15mm (but 13mm is pretty close)
Rigging Doctor for SK99: 10mm

The choices get more tricky as Liros don’t make every size (no 7, 9 or 11mm).

For the moment I’m thinking of 8mm for the Mizzen (might be a bit stretchy but at the end of the day it is only the mizzen and normally loads are low because it doesn’t have a genoa). I might have gone for 9mm if Liros offered that.

For the Main I’m thinking 12mm (larger than either the Colligo and Rigging Doctor calculations) and the largest size of Liros D-Pro-XTR available).

[Update] or 9mm DynICE Dux for the Mizzen and 12mm for the Main

100m of the 8mm should be plenty for the Mizzen with enough spare to replace several shrouds.
Possibly from our back of the envelope calculations 150m of the 12mm for the Main should also give enough for several replacements. We won’t be re-rigging the main until after the 2021 season so have plenty of time to measure properly.

In the design of the Dyneema chaimplates I mentioned sizing them up, but of course the line is doubled so I’ll use the same size for the chainplates as for the shroud/stay attached to them.

One area still to be worked out is how much length to allow for creep. I need to ensure that the lashing length is enough for me to still tension the shroud at the end of it’s life.

This post has taken an age to research and write. It is based on our specific boat and shares our thinking for our uses. We are not experts but just trying to show our thinking processes. Don’t trust us for the sizing of your own rig!

Dyneema forestays and backstays

All the posts I have been writing about Dyneema rigging and chainplates have been mostly focused on Shrouds (the standing rigging that holds masts up from the sides). Much of it also applies to Stays (the standing rigging that holds masts up from the bow and stern of the boat). However, there are some differences, for us especially because we have a ketch rig (two masts).

So I’ve been checking out how to apply the work I’ve done for Shrouds to Stays. It is quite different for our Mizzen and Main mast so I’ll write about them separately.

Main Mast

As I have mentioned in other posts (eg Why Dyneema standing rigging?) we are not going to be replacing our forestay with a Dyneema synthetic rope. The roller furling for our genoa would chafe through a Dyneema forestay very quickly as it puts the forsetay inside a metal tube that is rotated to roll up the sail around it.

However, we are planning a removable inner forestay (see Progress on Sails for our first mention of this) and this will be Dyneema. With all that we have learnt we will probably fit a DIY Cheeky Tang (see Dyneema Termination and Chainplate update) for this. Earlier we would probably have used a Bluewave Forged T Eye (as mentioned in Termination of Dyneema Shrouds. The most contentious issue?), however, if this is to be capable of acting as an emergency forestay, holding up the whole mast, then we will want a thicker line than 8mm.

Our current plan for the inner forestay is to have it as far aft from the bow as we can manage. The limits are set by the space required for the dinghy on the deck and where we can reinforce the underside of the deck enough. This will allow us the option of setting a staysail so we have a cutter rig (two smaller jibs instead of a genoa). Depending on how high we fit it to the mast we might need to add running backstays (which our mizzen already has so see below).

To hoist a sail at the inner forestay we will need to add a sheeve to the mast just below where the inner forestay attaches for the halyard (and at the bottom for the halyard to come back out of the mast).

Our backstay is currently slightly complicated and the tension can’t be adjusted (something you often want to do when sailing to control the tension of the forestay which changes the shape of the genoa).

It starts with a single wire at the top of the mast.

Part way down the single backstay is split so that one can go each side of the mizzen mast.

I’m assuming this is to save weight, although it might also help avoid the back of the sail (the leech) from rubbing on the backstay when sailing upwind (the sail won’t be pulled in as far as the centreline where the single backstay section is, but it might be pulled in far enough to rub against one of the double lines if they go all the way to the top of the mast (because the sail “sticks” out from a straight line from the top of the mast to the end of the boom – this is called “roach” and it is supported by sail battens). Our current sail doesn’t have roach but the original design adds 21 square feet of roach (and it is in a very efficient place near the top of the sail).

The problem with the single to double backstay is that instead of having the safety feature of two independent backstays you have multiple single points of failure.

So looking at where the single backstay attaches to the top of the mast.

I’m thinking we can replace that pin with a longer bolt and two DIY Cheeky Tangs so that we have 2 independent backstays right from the top of the mast. With Dyneema lines being so light we would save a lot of weight and add redundancy.

If we find that we need the backstay central at the top to miss the sail then we can add a couple of low friction rings to pull the two lines together at an appropriate point. If one backstay fails then the other will be a bit slack but will still be there.

A similar technique is commonly used to tension the backstays. A line with a low friction ring is used to connect the two backstays. This line is then pulled down to pull the backstays together (and tension them) or slides up to allow the backstays to separate (and follow a more direct line) thus slackening them. This technique automatically compensates for any differences in the tension of the two backstays (the slacker one always moves more inwards to balance the tension).

Mizzen Mast

Our mizzen mast doesn’t have a forestay or a backstay. A forestay would stop the main boom from being able to swing from side to side. A backstay would require a much shorter mizzen boom (and so smaller sail) or something sticking out the back of the boat to fasten it to.

So instead we have 2 shrouds that come forward from the top of the mizzen mast to the sides of the boat. The main boom just misses them. These stop the mast falling backwards.

Then we have two shrouds (side stays) that start just below the spreader and are angled slightly aft. These stop the mast falling forward but as they do not go to the top of the mast they are not enough to hold the mast up if the sail is pushing forward. For this we have running backstays, one each side. These provide the extra support for the mast, but to let the sail out fully they have to be released. So when you tack or gybe you loosen one and tighten the other so that the boom can move across the boat.

The net effect is that our mizzen basically has 4 shrouds per side. One per side is a running backstay and so you need a means to tension and release it as needed. As far as replacing them with Dyneema there is no need for any difference in the shrouds themselves.

Remaining issues

  • We need to finally confirm the current sizes of the stainless steel wire (need to be allowed back to Wales).
  • Then we can finally calculate the size of Dyneema to replace our stainless steel wire.
  • We need to decide where to protect with a Chafe/UV sleeve.

Other than that we are close to getting on with building and fitting it all 🙂

Dyneema Termination and Chainplate update

Following my posts Chainplates. We are going for a radical dyneema option and Termination of Dyneema Shrouds. The most contentious issue? I’ve just watched a new video from Free Range Sailing “Our sailboat REBUILD begins ⛵💪 – Episode 157

They are also fitting dyneema chainplates (so far, just for their backstays).

Their solution is a little different to ours. In part, that is because their backstay chainplates don’t have to be waterproof, as they go through the stern from outside to outside. So their solution of two holes and 3 loops of a lighter lashing line isn’t quite right for us. Our use of the softshackle overhand knot to create a loop is better for us as we only need one hole to fill and there is no need to balance the lengths of multiple loops of a lighter line.

However, their use of a HDPE tube to run the Dyneema through is very interesting in one obvious and one less obvious way.

In our Dyneema chainplate design we are making the hole through the deck by creating a thickened epoxy section of deck, drilling through it and then smoothing the epoxy to avoid chafe. If instead we fit a HDPE or possibly a UHMWPE tube though the thickened epoxy then it should reduce chafe even further. We could also have it stick up above the deck a little to avoid as much water running into it (and no danger of gravel on the deck getting into the Dyneema and cutting it. Having an up-stand will make it easier to seal and provide an attachment point for our chafe protection to fit to.

That got me thinking about some strips of RG1000 (basically recycled UHMWPE) that we bought to allow our solar panels to slide on a solar arch (which is currently on hold until we have launched and got a Hydrovane self steering fitted). Anyway RG1000/UHMWPE has some brilliant properties:

This engineering plastic can be machined into virtually anything, from small (low load)gears and bearings to huge sprockets-shapes that until recently were only possible with metals. It not only outperforms metal in abrasion applications, it’s also easier to machine and therefore cheaper. This versatile plastic can be milled, planed, sawed, drilled, and turned to create a huge variety of parts at a very competitive price. It possesses outstanding abrasion resistance, superior impact resistance, non-sticking and self-lubricating and excellent mechanical properties, even in cryogenic conditions.


I’m therefore thinking that this would be a great way to make the our DIY cheeky tangs. If we started with a metre long length of 70mm diameter rod (costing under £60) we could make plenty of tangs for both masts and some spares. All we would need to fit them would be longer replacement bolts. I’m sure we could use the dremel to cut smooth guides for the shrouds. If we drill the hole for the bolt above the centre then they will stay the right way up (making some form of retention possible). We are currently leaning towards either 11 or 12mm Dyneema for the standing rigging (the Colligo Marine recommendation to replace 8mm 1×19 Stainless Wire is 11mm). Using a 70mm rod would allow us to create nice guides while keeping a bend ratio of more than 5:1 for maximum dyneema strength. It would also allow us to figure out way of doing line retention (maybe as simple as a light dyneema line across the top of the tang?). We would not need thimbles (a significant cost saving) and we could fit chafe/UV protection to the eye splices as we can size the groove guides to fit (finding closed thimbles for 12mm Dyneema that has a chafe sleeve is proving very hard and the only option I’ve found is 16mm which very oversized and very heavy (and that does mean that despite my misgivings we might need to use low friction rings at the lower end of the shrouds due to availability and weight).

Again, just like the chainplate solution these DIY tangs give us something we can easily inspect for wear and we can carry replacements that we can fit ourselves anywhere in the world.

I’m also suddenly realising that these rods might also be the solution we need for our bow roller. 🙂

So very, very happy with this.

Brilliant English Upcycling of old sails

Today I found Sails and Canvas (in Topsham, Devon):

Lifestyle products
Made in Devon
from recycled sails

Absolutely brilliant! 🙂

We will have to sail to Topsham and on the way decide which of our many very old sails are past being usable for us so they can become great new things 🙂

Thanks to Clean Sailors on twitter: Follow @CleanSailors and @SailsCanvas (as well as us @SustainSailing of course)

Termination of Dyneema Shrouds. The most contentious issue?

When you look at the strong opinions about the way you end your Dyneema shrouds it makes all the other strongly held opinions seem conflict free 🙂

This is a bit chicken and egg in the sense that decisions about

a) how you will tension your shrouds at the connection to the chainplate and
b) how you can connect shrouds to the mast

will have a definite impact on which options for terminating your shrouds are relevant.

There are very strong opinions expressed with fervour about how strong some of these solution are and how long they might last. Some people will argue that some solutions must not be used to cross oceans yet I think people have crossed oceans with all these solutions.

So what are the options?

  • Plain eye splice with optional chafe sleeve. I’ve only seen this suggested at the mast. There the eye splice can be either hooked over a Colligo Cheeky Tang [Tula’s Endless Summer] or a attached to the loop of a stainless steel T fitting with a luggage Tag loop (sometimes called a Cow Hitch) [Free Range Sailing].
  • Eye splice onto a Low Friction Ring. Can be tensioned with a lashing or lashed to something else such as a shackle. [Free Range Sailing]
  • Eye splice with optional chafe sleeve onto an open stainless steel thimble. Can be used at top of bottom of a shroud, plus for deadeyes [Rigging Doctor, Sailing Zingaro]
  • Eye splice with optional chafe sleeve onto closed stainless steel thimble. Can be used at top of bottom of a shroud, plus for deadeyes [Sailing Zingaro, Tula’s Endless Summer]
  • Eye splice with optional chafe sleeve onto a Colligo line terminator. Can be used at top of bottom of a shroud, no need for a deadeye [Tula’s Endless Summer]
  • Blue Wave stainless steel eye clamped to Dyneema. Can be used at top of bottom of a shroud (with a turnbuckle) [I haven’t seen these in use].

So I’ll consider them all and how they are typically used at the mast or chainplate as appropriate. First a picture of each (I haven’t included every combination of a chafe sleeve or not.

Colligo Marine Through Bolt Cheeky Tangs
Bluewave Forged T Eye
Dyneema loop on low friction ring
Deeadeye using open thimble with chafe protection by Rigging Doctor
Kraken structures Deadeye, closed thimbles, chafe protection.
Bluewave Dyneema Rope Eye

Opinion Time

Or duck and run time?

If you can afford it then Colligo Marine have stock items for every type of mast connection (of which, if your mast is suitable I think the Cheeky Tang is brilliant for saving weight and reducing the number of components and connections) and for the chainplate they have solutions for both turnbuckles and lashings (or both). They are really well sorted for ensuring the Dyneema bends very gently and also that loads are very evenly distributed to Clevis pins etc.

But at the same time the Colligo Marine stuff is really expensive. We would be talking about thousands of pounds per mast. So they are far outside our budget.

Some of the solutions concern me. Attaching a Dyneema loop to anything by a Cow Hitch or Luggage Tag does not seem suitable for a critical high load like a shroud. To me the bend radius looks very tight and will surely be a weak point.

Also I’m not keen on the Blue Wave terminals (they have a range of them with different connections). I’m sure they are carefully engineered but for me a key safety feature of Dyneema is being able to visually inspect it.

While I think Low Friction Rings are awesome for lots of applications, I’m not convinced that they are a good fit for this purpose. If you fit a large eye splice to avoid a tight bend then it looks like the low friction ring could fall out. If the ring is held in firmly then either the dyneema has to bend sharply or there is a lot of time consuming labour to apply whippings. Even then if the ring is used for tensioning via multiple strands of lashing line people have reported a tendency for them to bunch together and jam.

I think the open thimbles look a bit problematic. In some of the images they look like they have opened up and an open sharp end is very close to the dyneema. It feels to me as if they are a bit close to a catastrophic failure if something catches on them and bends them open.

With both types of thimble a critical issue is what they are attached to. With their first attempt Sailing Zingaro used wide toggles into the thimble and it created point loadings on the sides as they didn’t sit properly. With a Cleivis pin the diameter of the pin might be so small relative to the thimble that again their is a point loading. This is most likely to be a problem at the mast end when trying to find a way to connect to the existing fittings on the mast (or a deadeye to a metal chainplate). Thimbles are at their best with a lashing either for tensioning or to lash them to something.

Conclusion for Vida

Now that we have decided on our Dyneema chainplate solution (but with a closed stainless steel thimble instead of a low friction ring) the lower end of our shroud is obvious, a matching closed stainless steel thimble. That should make tensioning as simple as possible and it is a pretty cheap solution. As our chainplate solution means we don’t need a deadeye or a toggle we save quite a bit of money and weight.

The top of the shrouds is more tricky. Consider this example of what we have now.

All our shrouds end up at through bolts and there are these riveted plates to stop the bolt holes becoming elongated. All the current shrouds have swaged end fittings that are held by a clevis pin through two plates (or tangs). On the mizzen we have 4 x single connections and 2 x doubles. On the main we have 2 x double and 2 x single (I am ignoring the main mast backstay and forestay at the moment).

One option (the cheapest) would be to get longer clevis pins and prise apart the plates/tangs far enough to fit a closed thimble in (but if we are looking at 11mm Dyneema shrouds on the main mast that is going to be quite a lot of bending of the stainless steel).

Another option would be to fit slightly longer bolts through the mast so that instead of bending the plates/tangs apart we separate them at the bolt with a few washers. We still fit the longer clevis pins.

If we could afford it then Colligo Cheeky Tangs would be great.

We are looking at a fourth option which is to make our own version of a Cheeky Tang. We start with a longer bolt through the mast. On each side of the mast we have a two large penny washers with the largest diameter spacer we can find between them (looks like about 25mm). A dyneema look goes over the spacer and the penny washers stop it falling off. That gives a bend radius of over 2:1. We would join the tops of the penny washers with a small bolt (or maybe a cable tie) to stop the dyneema loop jumping out. The lower side of the outer penny washer would be cut away to provide a smooth route out for the dyneema.

No decision yet until we get the sizing sorted and see how the thimbles fit in the existing tangs.

Big update: see Dyneema Termination and Chainplate update

How sustainable is Dyneema rigging?

Until recently the answer would be: terrible. A “plastic” made with petrochemicals that can’t be recycled.

However, things are changing.

There is now a Bio-based Dyneema fibre which has International Sustainability and Carbon Certification (ISCC).

What isn’t quite so clear is which companies are using this and in which products. Marlow ropes announced that they were using Bio-based dyneema in July 2020. Liros also have an announcement but I can’t find product detail. Given it is so new it might take a while to work through the supply chain.

There are also initiatives to accept “retired” ropes back for recycling, it looks like we can be fairly confident that any ropes we buy now for standing and running rigging as well as dock lines etc will all be recyclable (and some companies like Marlow are already making some ropes from recycled plastic).

I confess I’m pleasantly surprised by what I have found. Looks like this is much better than I expected. The only issue will be the microfibres of plastic that get shred into the water during the lifetime of the ropes. Not sure what can be done about that, but at least compared to other forms of plastic pollution this is a significant improvement.

[Update] thanks to twitter there is another option for Bio-based Dyneema: Gleistein

Gleistein is adopting the world’s leading role among textile rope manufacturers – being the first to switch its entire production of products made with Dyneema® to bio-based fibres. Read our factsheet: