Continuing Solar planning

Sadly, we can’t do much but plan at the moment. However, that does at least give us the opportunity to improve those plans.

In More on sustainability, I included a bit about Jimmy Cornell needing to abandon his attempt to sail around the world with zero carbon emissions. So another incentive to improve our plans.

This is what we have so far:

Wheelhouse roof

4 x 40 watt panels (total 160 watts) for the top of the wheelhouse roof. To be connected so that the two sides are in parallel reducing the impact of the considerable shading as the main boom is just above the wheelhouse.

Guardrail mounted

4 x 175 watt panels (total 700 watts) to be fitted alongside the guardrails. They will be moveable, tiltable and removable. So we can have up to 4 on either side of the boat (to catch the sun). While sailing we should be able to have 2 per side (positioned about 3/4 of the way aft), with the option to drop them to be vertical (like canvas side dodgers but with a gap for water drainage below them) for docking or if waves are a problem. But there are plenty of people sailing with these pretty permanently mounted (eg Rigging Doctor, Millennial Falcon, Sailing Project Atticus). We can also remove them and store them below in really bad weather (recognising that ours are larger and hence more windage).

We have been exploring lots of potential ways of fitting these. Quite a lot will end up depending on how our budget goes over the next few years, we explored a cheap getting us started option using lightish timber struts. However we now have a better solution Simplifying guardrail solar panels.

Longer Term Plans:

By adding a solar “arch” (see below) we should have a grand total of 1460 watts. That is more than Jimmy Cornell, plus we will be able to rotate and tilt most of them to improve efficiency. Coupled with significantly reduced power consumption (only 2 people, wind vane steering, only one fridge, no electric winches etc) we think we are heading towards the right ballpark figure.

Solar Arch.

We have lost count of the number of design options we have been through. Here was one. It got pretty complicated as we work around all the constraints. Our fairly narrow stern, mizzen boom and need for Hydrovane self steering make the structure very challenging.

Our current thinking is to mount two 300 watt panels almost completely independent of each other (total 600 watts). Through a combination of rotating and tilting we will be able to position them for maximum efficiency while also being able to have them either clear of the mizzen sail (ie sticking out aft beyond the boat length) or safe for docking or storms (ie extending forward over the mizzen boom and aft cabin) at which point we would not be able to use the mizzen sail. They will also be removable, even at sea so that again we can stow them (probably on deck due to their size) if needed.

Our plan is to first shorten the mizzen boom as much as we can for the existing sails. Longer term we might get a new mizzen sail with a shorter foot but fully battened with a fathead sail (google images of Fathead mainsails), that would keep the boom further out of the way,

Then the implementation we have agreed with Hydrovane puts the actual vane a little higher than normal so that it is clear of the mizzen boom and sail (thus allowing us to tack without having to touch the vane mechanism).

The solar support will start with an upright carbon fibre tube in each aft corner of the deck (or possibly just down the transom a little), these will be positioned so that they are just clear of the boom as it swings across. They will have a diagonal strut going forward and another diagonal going across the stern. There is a vast array of carbon fibre tubes available up to 54mm diameter so we have some calculations to do. We will mount a smaller carbon fibre tube through the deck that will go down to the full where it will be epoxied in, this will stand clear enough of the deck for the main upright to drop onto it and be close to fully self supported, the struts will add more rigidity as a precaution.

The top 500mm or so will be above the diagonal struts and the top part will be filled with thickened epoxy. This is then a base onto which the pole for the solar panel drops. These Carbon Fibre Tubes are designed so that each size slides into the next size up. So the poles for the panels will be one size up from the fixed upright tubes. They too will have a thickened epoxy filling in key places but leaving 500mm open to drop onto the upright tubes. Connecting the tubes this way allows the upper section to be rotated or removed. We will have a hole for a pin will allow the rotation to be locked in two places (and will also stop the top tube lifting off).

A smaller tube will be fitted horizontally to the top of the solar panel upright. Using a smaller diameter will allow us to attach it by through drilling the upright for the horizontal to fit though. The joint area will then be filled with thickened epoxy to lock everything in place. The horizontal tube will only project out on one side of the upright (like an inverted L). Using the rotation and locking pin this can be forwards or backwards from the upright. This horizontal will be approximately 3/4 of the length of one of the solar panels.

To attach the solar panel we have two slightly oversized square tubes. These are the long enough to be fitted to the solar panel (going across the width of it). They have holes drilled in the middle, with short lengths of tube (next size up from the horizontal) fixed into them so that they can slide onto the horizontal tube. This attached the solar panel and allows it to tilt.

To support this we add a smaller tube as a diagonal brace between the upright and the unsupported end of the horizontal tube. At which point it will look a like we have a pair of gallows on the boat with solar panels on top 🙂

All the fixed joints will be created by smaller diameter tubes going through the larger, the smaller tubes will have smaller holes inside the joint so that when the joint area is filled with slightly thickened epoxy they get locked into place. We will also use epoxy fillets on the outside of the joints.

We will use dyneema guys to control the tilt of the panels with the option to use them to lock the rotation in other places than the locking pin allows.

To remove the panels we will use a halyard. We will rig it so that the pull is up a topping lift, that means as the upright tube comes free the whole thing won’t swing wildly about into the mast.

This give us multiple positioning options:

  • Preferred sailing option. Turning the panels aft so clear of the mizzen, with the ability to tilt them either for maximum solar efficiency or for minimal windage (compensating for the boats heel) depending on the conditions.
  • Preferred docked option. Turning the panels forward, the mizzen can’t be used but they are fully within the deck outline so not going to snag on other boats or be a hazard to people on the dock.
  • Moderately bad conditions. Assuming that you have taken the mizzen sail down, turn the panels forward and take the tilting control lines forward for maximum stability (better angle and braced to the deck rather than the support post).
  • Storm conditions expected (whether sailing, at anchor or in a marina). Lift the panels up so the uprights come off the fixed supports (using a halyard that has a low friction loop so that it runs up the mizzen topping lift giving a close to vertical lift). Lower to the deck and secure.
  • At anchor. Rotate and tilt so the panels are close to right angles to the sun, adjust to compensate for both the boat and the sun moving.

Safety

There are obvious concerns about having large panels relatively high in the air. However, there have now been multiple Atlantic crossings by boats similar in size to Vida with panels this size on solar arches.

We do recognise that our design is a little different due to the complications (mizzen and hydrovane). We do not think this design is possible with the typical stainless steel tubing designs. However, carbon fibre tubes can be used for a wide variety of purposes including masts and wind turbines, that support significant loads on unstayed uprights.

Unlike other solutions we have a variety of options do deal with different conditions. We are not creating a fit and forget solution but one that fits with our expectation of Active Solar Generation which we believe is a critical factor in achieving zero fossil fuels. The real potential to increase solar generation isn’t clear but a 30% increase is possible when you can angle correctly and far more if panels can be moved to avoid shading.

Wind generators

We can potentially add a similar pole support base on each side of the boat by the mizzen mast. In suitable conditions a wind generator can then be deployed. Again using the active generation principle. Wind generators are only effective in certain conditions, so why would we want the noise and windage all the time? However, they are the best option for reducing the need for a generator when we need electric power for heating while anchored in winter when there isn’t much sun.

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.

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!
[Update]
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[End Update]

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

[Update] I have written a lot about Dyneema standing rigging so I now have a guide to it all in: Dyneema / Synthetic Rigging Summary[End Update]

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

[Update] I have written a lot about Dyneema standing rigging so I now have a guide to it all in: Dyneema / Synthetic Rigging Summary[End 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.

UHMWPE Rod

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.

Update, having read more I’m not entirely convinced that HDPE or UHMWPE will resist the static loads that a tang fitted to the mast needs to handle. I’m now thinking that 2 or 3 circles of G10 epoxied together might be a better option.

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?

[Update] I have written a lot about Dyneema standing rigging so I now have a guide to it all in: Dyneema / Synthetic Rigging Summary[End Update]

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

Why Dyneema standing rigging?

[Update] I have written a lot about Dyneema standing rigging so I now have a guide to it all in: Dyneema / Synthetic Rigging Summary[End Update]

We know that our decision making process can seem strange to others. 🙂 For example why would we remove a working diesel engine to go for an electric motor. We imagine there will be many who will also be wondering why on earth we are switching from “normal” stainless steel rigging to Dyneema (just to be clear not all at once though).

Vida has a Ketch rig. So two masts and they are entirely independent of each other (no Triatic stay connecting them). We think we are the only Rival 38 with a ketch rig (one other has been converted from ketch to sloop). It is something we like, not just because ketches look great.

We love the safety features of a ketch, obviously having a spare mast to get you home if one breaks is a big one. Having more but smaller sails makes things lighter to move, hoist, reef, and trim. There are more sail plan options when the wind gets up (or if something breaks). The mizzen can be used to stabilise the boat both when sailing and when at anchor.

Against that there is more stuff (to buy, inspect and maintain), more weight, generally slower performance (particularly upwind where the mizzen doesn’t help much and adds windage).

When it comes to the rigging the costs are clearly higher (not quite double because while there are about twice as many components they are smaller sizes than they would be with a sloop rig).

Current condition

The mizzen mast is a replacement (not sure when or why it was replaced). The main mast is sound although it has had quite a few changes made to it over the years and needs some freshening up. We have removed the mainsail roller furling which had been fitted to the back of the mast and got a new boom with slab reefing.

The rigging is about 8 years old (but some of it is original) and insurance only provides cover for the first 10 years.

So we know we need to be working to refresh the rigging before we end up living aboard and crossing oceans in a few years time.

Staying with Stainless Steel

When it comes to refreshing the rigging the obvious choice would be to get a professional rigger to do the job and stay with stainless steel. We would have to change a lot more of the rigging if we did it ourselves as the stainless steel wires go into swage fittings and that isn’t a DIY option. Alternatively at considerable cost when changing the stays we could switch to Sta-Lok fittings which we could fit ourselves.

As we are refitting with the goal of living aboard and world cruising in a few years we are taking a long term perspective.

As you replace more things to achieve longer term peace of mind and reliability the cost of staying with stainless steel grows. At the moment it is all a bit of a mixed bag of original and replacement parts. We don’t have detailed records of what was changed when. So we have a mixture of stainless steel (main mast) and original bronze (mizzen) turnbuckles. We have a mixture of stainless steel and bronze toggles. Some of the bronze toggles have stainless steel pins and some still bronze. We have all original bronze chainplates which have not been removed and checked (I have written several posts about the issues and our solutions, start here). Some of the connecting plates etc at the mast are starting to rust and there are mixtures of stainlesss steel and aluminium components where there is some galvanic corrosion.

We would be looking at thousands of pounds to completely re-rig in stainless steel and that would probably need to add having custom made stainless steel chainplates that would have a known condition and be long enough for better backing plates.

So Dyneema?

Dyneema has been used for boat rigging (in small numbers) for about 20 years. See this: DYNEEMA RIGGING Q&A PETER GREIG which includes:

Insurance companies are accepting Dyneema rigging. It has been around for 20 years and there is no recorded failure anywhere in the world from professionally done splicing. However stainless steel cases have a huge amount of claims

Dyneema rigging potentially will outlast stainless steel. Only severe chafing from something very sharp could affect it, but the same way it would affect wire anyway. I have recently worked on a boat that I rigged 15 years ago and which has done 6000 miles in that time – there was absolutely no deterioration visible.

Advantages

  • Weight. Much, much lighter than stainless steel. This reduces the loads on the boat and reduces heeling making sailing faster and more comfortable. This has driven the adoption on racing boats.
  • DIY. Dyneema line is easy to work with using very basic tools. So it is perfectly possible for us to do all the work ourselves.
  • There are no special components (especially to connect and tension wires), so a cruising boat can easily carry the spares needed to re-rig the entire boat anywhere in the world. Potentially all you need is line, thimbles and low friction rings. Not only can you carry everything but it is small, light and won’t rust.
  • Stronger. Dyneema rigging has to be sized for stretch which means that when you size for the same amount of stretch you have many times more strength.
  • Inspectable. There are no hidden parts, all the Dyneema can be seen and checked. The two forms of damage (chafe and UV) are very visible long before failure.

Disadvantages

  • The line itself is expensive (100m of 8mm 1×19 Stainless Steel £576 vs 100m of 11mm Dyneema £1,360)
  • Dyneema is stretchy compared to Stainless Steel so you have to fit larger sizes (eg as per above 11mm instead of 8mm).
  • Dyneema is vulnerable to chafing (rubbing) wear. However, problems are very visible and it is possible to protect it with sleeves or seizing.
  • Dyneema is vulnerable to UV degredation. Again this is visible when it happens and most chafe protection will also provide UV protection.

Conclusion

We are switching to Dyneema first for our Mizzen mast and then for the main mast (except the forestay) for the following reasons:

  1. We can do everything to switch to Dyneema rigging ourselves which saves a lot of money.
  2. We can sort our concerns with our chainplates to solve the weakest link in the rigging with something that is stronger, that we can inspect, repair and replace ourselves.
  3. We will save a lot of weight which will improve our sailing performance and comfort.
  4. We can carry everything to be able to re-rig everything, anywhere.
  5. We will not have to rely on others expertise to properly check the condition of the rig.

In return we recognise that we are likely to have a few hassles

  • We might have to hunt more carefully for surveyors and insurers
  • Tuning the rig will be a slower process (we are going to be using lashings to tension the shrouds and they are slow to untie, tension and tie up).
  • More work to get us afloat the first time because we are not “just managing” with the problem chainplate.

Outstanding Issue

We will not be able to replace the forestay with Dyneema as we have a roller furling system. This includes an aluminium extrusion which covers the forestay and rotates to roll up the genoa sail. This would quickly chafe through the Dyneema. We don’t plan to review this until either the genoa sail or the roller furler need replacing.

Plans

Mizzen mast first due to the problem chainplate. Making the smallest changes to the mast that we can, so reusing the existing connections as much as possible.

Sail for at least one season.

If all has gone well then do the same to the Main Mast.

At some point in the future upgrade the mast connections to use Colligo Cheeky Tangs for simplicity, strength and weight saving (but this will cost a couple of thousand pounds). The good news is that this change wouldn’t require any changes to the rest of the rigging (just slip the top thimble out so the eye splice goes over the Cheeky Tang. This will shorten the shroud/stay a little but the lashing will be able to cope with the change.

Chainplates. We are going for a radical dyneema option

[Update] I have written a lot about Dyneema standing rigging so I now have a guide to it all in: Dyneema / Synthetic Rigging Summary[End Update]

In my last post “Chainplate update, more challenges” I linked to a whole bunch of YouTube channels where people have switched their rigging from Stainless Steel Wire to Dyneema Synthetic rope.

I’m going to write more on why we plan to switch to Dyneema, fully recognising that this is not yet seen as the norm. Also on the connections that are needed at the mast end of each shroud/stay.

Here though, I’m focusing (again) on the chainplates. I’ve detailed the problems we have with our chainplates, although it is worth noting that these problems are not typical of other designs. We don’t see many boats with bronze chainplates and we don’t see many boats where the chainplate is basically just a bronze eye bolt through the side deck with a backing plate (the chainplates for our main mast cap shrouds are bolted to right angle connection from a plate bolted to the bulkhead rather than just a backing plate).

Normally on boats this age, there is a long stainless steel plate that goes down into the cabin with multiple bolts either to the hull of the boat or to a main bulkhead. This plate sticks out of the deck for the shrouds to attach to it. With newer, higher performance boats the engineering of these has to be much more sophisticated as rig loads are greater and the general material in the hull much lighter and thinner.

What we have seen is that it is very normal to need to refurbish or replace the chainplates on boats that are over 40 years old especially when there are plans to cross oceans. So we have seen Tula’s Endless Summer, Beau and Brandy, Kittiwake, and others who have had to do this work. There have been a variety of solutions from upgrading to Titanium, direct replacements, or switching to through bolted external chainplates.

Going Dyneema.

We however, are not looking at a refurbishment (doesn’t solve the problem of the thread being too short for a thicker backing plate) or a replacement with similar (cost and not ideal attachment point for Dyneema shrouds).

When thinking about our chainplates while planning for Dyneema rigging one of the practical issues to sort is the attachment points. I will do a separate post about our plans for the ends at the mast. At the lower end you need a means to tension the shroud and a way to attach it to the chainplate.

As I have been reading about Dyneema rigging it has struck me that lots of people have multiple extra fittings to adapt the connections at the ends. It allows existing chainplates and mast fittings to be reused, essentially via adapters.

So if we have got to do work on our chainplates anyway I started wondering if it would be possible to end up with a chainplate which we could directly connect the tensioning lashing to. The only solution on the market is the Colligo one but that would cost hundreds of £ per shroud and would not solve any of the problems with the chainplates themselves.

Then as I was searching I found these Soft Padeyes

These are not generally being used as chainplates for shrouds, but for sheeting, temporary attachment points, removable inner forestays and the like. Most boats won’t be able to consider these for their chainplates because

  • they only make sense for dyneema shrouds
  • they only make sense if you are tensioning your rig with dyneema lashings, not turnbuckles
  • I’ve only worked out how they can be used to replace chainstays like ours that are in the side deck and that don’t have engineered ties to the boat

But for us, I have realised is that it should be simple for us to make these ourselves, using the backing plates we have already designed. Not only that, but they will be easy to inspect at sea and even replace at sea ourselves if needed.

Making and fitting the dyneema chainplate

Updated design now completed see Next generation Dyneema Chainplates.

I don’t think it is going to be very difficult – but don’t hold me to that 😉

  • Remove the existing chainplate and old backing plate.
  • Drill out a significantly larger hole where the chainplate bolt was. This is to make sure that we get to clean dry deck core. Later it will be filled with thickened epoxy and then a hole drilled in the epoxy for the dyneema loop. This way the deck core will be protected from damp by the epoxy. It also means we will have the option to angle the hole so that it is aligned with the shroud (currently they are not).
  • Now fit the backing plate using thickened epoxy so that the hole in the deck is in the centre. We might apply pressure from below or drill a small hole in the centre to allow a light line to pull it up tight through the deck hole.
  • If this is one of our more heavily loaded chainplates (eg main mast backstays or cap shrouds) then we will add the additional bracing to the hull.
  • With the backing plate fitted we can now fill the hole in the deck with thickened epoxy.
  • Drill from the deck through the thickened epoxy and through the backing plate. Hole should be big enough to thread a doubled dyneema line through from below. I’m going to use dyneema one size up from the size used for the shrouds and I’m going to cover it with a chafe sleeve.
  • Round and smooth the edges of the hole at both top and bottom to minimise chafe when the loop is tensioned.
  • Make a dyneema loop. I’m going to follow a simplified version from the video below. It uses a very simple overhand knot which can’t slip because the loop is passed through eye splices that stop the knot from slipping. It seems to have a lot of advantages for this (easy to create, large knot, very strong and tested). Mine doesn’t need the soft shackle eye which makes it even simpler. It will just be a loop, closed by the knot at the open end. This probably needs to be about as short as I can make it because we want to keep the loop above the deck as small as possible, just suitable for a low friction ring or stainless steel thimble.

At this point we could just thread the loop up through the backing plate and deck, then put the low friction loop in it (and if we wanted a padeye on top of the wheelhouse roof this would be fine).

However, it will leak.

Stopping Leaks

One option for a waterproof version is to buy this complete solution from Colligo for about $80 (for the waterproof version), but they only go up to 5mm with 5,000 lb breaking strength.

Alternatively we can make our version waterproof while still keeping it easy to replace ourselves.

For this we need a “washer” made from the same material as our backing plate. The outside diameter should made to just fit inside a short length of plastic pipe. Choose a pipe that is large enough for the knot to easily fit inside it, also a pipe that we can get a waterproof end cap for.

Epoxy the washer onto the backing plate so that the hole lines up. So that the knot fits well against the washer. I will make a large countersink around the hole in the washer (making sure it is nicely rounded and smooth). We are consideing lining the countersink with a thin hard rubber to spread the load a little more evenly over the knot.

Now we fit the length of pipe over the washer so that it is long enough to hide the knot (a marine sealant should be enough to attach it). Any water seeping down the dyneema will be caught in the pipe and you can remove the end cap whenever you wish to drain the water and inspect the knot or even replace the dyneema.

We will put some silicone sealant around the loop as it comes through the deck to reduce the amount of water that can seep down and stop debris slipping down and damaging the dyneema.

If the loop sticking out of the deck is quite long, I’ll put a whipping around it to hold the friction loop/thimble in place.

The results

We will now have a dyneema chainplate. It will be a lot stronger than the dyneema shroud connected to it (because it is made from the next size up dyneema). It will be a lot lighter than any other solution.

There is nothing to corrode, there is nothing we can’t keep spares for and nothing that we can’t replace at sea.

Compared to all the other ways of attaching a dyneema shroud there are fewer components so cheaper, lighter and keeps the lashing much lower to the deck for improved looks and less chance of chafe or snagging on anything.

For improved looks, UV protection and chafe protection we will make covers for the lashings. Probably rectangles of Sunbrella material held on with velcro and ties.

Tensioning

Both Rigging Doctor and Tula’s Endless Summer have videos on how to tension dyneema shrouds with just lashings. Colligo themselves don’t suggest that for boats over 30feet. However, both Wisdom and Adreneline are much longer than Vida and as we have a ketch rig our masts are a lot shorter. We might have a slight advantage as our low friction ring will be so close to the deck that we don’t have to worry so much about it being pulled out of alignment as we tension the lashing.

Summary

Compared to every other solution for improving our chainplates and connecting dyneema rigging this seems much cheaper and easier to fit. Plus it is lighter, stronger, tidier, and more functional than any other solution I’ve found. Finally, we can inspect it, maintain it and replace it ourselves, even at sea which is fantastic.

What do you think?

[Update] See Dyneema Termination and Chainplate update

Further update: Updated design now completed see Next generation Dyneema Chainplates.

Chainplate update, more challenges

Back in June I wrote “Chainplate update” which explored how we might solve the problems with our chainplates that we detailed in “Deck repair question“.

We are very comfortable with our solution to the backing plates / under deck reinforcement: replace the inadequate stainless steel plates that have 4 problems

  • too small (so the load is not spread far enough which can cause the deck to crack or even complete failure)
  • made of two layers that can move out of alignment (then they can bend and cause cracking or complete failure)
  • no tie in to the hull (so the deck can pull away from the hull or crack or fail)
  • potential for corrosion due to mixed metals (bronze chainplate bolt with stainless steel rigging and stainless steel backing plates).

Note that while there seems to be a common view that Rival yachts have rather under engineered chainplates I have not heard of any actual failures. [Update]I have heard of a few failures now, including another Rival 38 where a chainplate failed mid Atlantic, fortunately they did not lose the mast[End Update].But the boats are getting older and we have deck cracking around one chainplate.

Our solution with 10mm FR4 board attached with thickened epoxy and the the option of FR4 ties to the hull is going to be a much better solution and one that is ideally suited to DIY. However, we have some remaining problems.

First, the thickness of the deck that the chainplate bolts go through varies. The deck rests on a shelf that is attached to the hull, as it would have been laid up by hand the thickness of the deck and shelf varies. That means a few of the chainplate bolts are barely long enough. So even with the inadequate backing plate the bolt doesn’t extend all the way through the 2nd nut which is used as a lock nut. With a thicker backing plate bedded onto thickened epoxy to ensure even load distribution it might not be possible to fit a lock nut. Any replacement is going to be very expensive (custom bronze fixtures). If they were stainless steel we could replace the double nuts used to lock them on with a nyloc nut and reduce the length of thread needed, but I don’t think these are available for bronze nuts.

Secondly, we have a long term plan to replace all the stainless steel rigging with Dyneema synthetic rope. We wrote about this back in October 2019 “Starting to sort out sailing“. More and more people are doing this (for example 4 YouTube channels have documented this: Rigging Doctor, Tula’s endless summer [my playlist of their videos], Free Range Sailing, Sailing Zingaro).

I’ll go through the dyneema rigging elsewhere, however, the relevant issue here is how to attach the dyneema to the chainplates.

[Update] I have written a lot about Dyneema standing rigging so I now have a guide to it all in: Dyneema / Synthetic Rigging Summary[End Update]

So far in the videos and reading we have done there are three options.

a) A toggle that allows a deadeye (see image below and how to make one by Rigging Doctor) to be attached via a clevis pin. We don’t have this sort of toggle (need Fork to Fork but we have Fork to Spade – examples of both here) at the moment (because of the style of rigging turnbuckle we have). This is the solution used by Rigging Doctor, Zinhgaro and some of Tula’s shrouds. However, none of them have bronze chainplates so there is no issue of mixed metals. So we have the expense of toggles, the risk of corrosion between dissimilar metals, and using a chainplate that has had 43 years of wear on the hole to which the toggle attaches. This solution is complex with so many different components (chainplate, toggle, deadeye, lashing to shroud) that have to be bought/made and fitted.

Dyneema Deadeye

b) A Colligo marine female Chainplate distributor which Tula used on some of their shrouds. Again we have the cost of these (we would need 14 and the price ranges from over £60 each to hundreds depending on size).

c) A frictionless ring attached to the chainplate by lashing it to a shackle (see the Free Range Sailing video at 15 mins). This is a whole lot cheaper as it is just a shackle and a frictionless ring (so under £20 per shroud).

All 3 solutions don’t solve the dissimilar metals problem as all of them connect something not bronze to the bronze chainplate. All of them rely on there not being too much wear in the 43 year old hole in the bronze chainplate and they don’t help with the problem of the length of the chainplate threads.

But we have come up with a creative solution that is going to be much cheaper, lighter, easier to maintain and stronger. Wait for the next blog post 🙂

For reference here is a grainy image of how one of our chainplates looks on deck.

To attach the rigging turnbuckle (that is used to tension the stainless steel shroud/stay) a toggle is fitted like this. It provides articulation to handle the different alignments of the turnbuckle and chainplate.