Wheelhouse plans

I said I was going to write this in my post “In the works“, just taken a bit longer than I thought.

This is what our wheelhouse looks like at the moment. The blue cover is really designed for use when Vida is ashore, or left on a mooring. It doesn’t have any windows and is almost impossible to do up fully from the inside. It is also all one piece which means you have no way of accessing the mainsheet or jib sheets when sailing.

Yes, we know that it definitely cannot be described as pretty!! The slab sections rising up from the cabin clash with every other line on the boat and it is too angular and too high.

However, we have a few more urgent concerns (although if we can make it look better while working on these then all to the good).

Ventilation: Even with the boat ashore in North Wales it got very warm under the wheelhouse on a warm summer day. It would quickly get unbearable to be at the steering wheel in the tropics.

Structure: the windscreen windows have vertical aluminium tubes between them. The stainless steel window frames are screwed to these on their sides and to the GRP at the top and bottom. This has caused corrosion between the different metals. Plus so far as we can tell the aluminium poles are not fixed in place by anything other than the window frames. That seems inadequate if a person gets thrown against it by a wave or a big wave hits it. Fortunately the poles at the aft end are very securely fitted.

Visibility: from our reading we are concerned that there are times when it is important to be able to look out directly rather than through glass (we have never sailed with a windscreen before so haven’t yet experienced the problems of rain and fogging).

Steering wheel: this has been repaired/strengthened before, it still doesn’t feel very strong. We are looking at replacing it with a slightly larger one (we can fit a 600mm wheel without hitting the side or blocking the hatch) should be nicer to use.

Seat: The original plans show a removable seat for the person helming with a backrest. Fitting one s1hould make it much more comfortable to be on watch for several hours.

Our plans.

We are still developing these, so still subject to a lot of change.

First, remove the existing glass a bit at a time and fit new supports that take the weight of the roof on their own. Probably use square section tubes of either stainless steel or carbon fibre. Possibly take them to the coachroof rather than to the existing windscreen base (to provide a bit more slope for better looks). That might allow us to change those big grey slabs at the the front of the wheelhouse so that they are slightly curved to blend in better (attach shaped rigid foam and cover with a fibreglass, then layers of epoxy fairing before paint).

Second, refit the glass (or switch to acrylic to match the rest of the windows and hatches except not tinted) but only go high enough to see through it when seated. So it would look much more like the fixed windscreens of a a Najad (see below). The effect would be a but like a windscreen with solid bimini above it. The key advantage is that when you stand to steer, you look out above the windscreen with your 360 degree view unimpeded by anything. This is a bit like what the Amel’s have (see Delos videos) but the dimensions are more horizontally squashed as Vida is 38 feet and the Amels 50 feet long. One other difference is that we would like to fit the glass/acrylic so that it can be hinged open or easily removed for maximum ventilation (this is one reason for switching to Acrylic rather than cutting toughened glass and sourcing new frames).

The next job will be to create a connection between the windscreen and the “bimini” (existing wheelhouse roof) that can removed/opened for ventilation and closed in cold/wet weather. One option is to simply continue with the lines of the windscreen to the roof, attaching to the support struts. Another option is to cap the windscreen with a shelf that extends into the wheelhouse (we need to do careful measurements to see if this is possible without always banging your head on it when coming in or out of the cabin). We could then have small, nearly vertical opening windows to fill the gap to the wheelhouse roof. The front of the wheelhouse roof would then be an eyebrow giving rain protection to the upper windscreen making it easier to see out in the rain. We have seen a number of boats with a soft fabric “window” in this position (although generally the bimini is further back and these removable sections are quite gently sloping (we just don’t have the cockpit length to do that).

Then we will create “curtains” or side walls for the back and sides (we have toyed with the idea of some of the sides being rigid acrylic). Unlike the existing blue cover we will have multiple sections that can be zipped in and out independently. They will also be mostly transparent (with protective drop down covers on the outside). We will be able to remove them and have mosquito mesh when appropriate. When not tacking much we should be able to sail with the windward side and 1/3 of the back in place if needed for warmth or sun protection. This will allow us to easily zip open (or closed) “door” shapes from both inside and outside making access easier whether at sea, at anchor or ashore.

At the moment we don’t think there is any point in replacing the wheelhouse roof for something a little shorter that might look better with some of the windscreen options. We certainly don’t want to “downgrade” from a solid roof to a fabric bimini that won’t last very long by comparison. If you want to sit fully exposed to the elements then by all means use the aft seat of the cockpit or sit on the cabin roof.

While this is quite a bit of work, the costs should be relatively low. Certainly it is far more sustainable to work with a 44 year old boat rather than buy something new. Improving the looks is the hardest challenge due to the space constraints (and the need for standing headroom). However, if we can improve strength, ventilation, visibility and access with much the same look then that will be a significant improvement for us.

Dyneema / Synthetic Rigging Summary

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

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

Our Chainplate journey

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

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

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

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

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

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

Attaching Dyneema

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

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

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

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

Sizing Dyneema

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

Sail plan and stays

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

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

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

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

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

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

Where to start?

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

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

Simpler Dyneema 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]

When I was coming up with the design of through deck dyneema chainstays and the update I had referred to this video from Free Range Sailing.

The key bits are are at 1m30s and 16m30s.

Since then I have had another idea, this should work for any boat that has strong bulwarks

I had ruled out exactly copying Free Range Sailing Sailing solution as it relied on being able to drill holes that went through the transom without going inside the boat. Therefore they didn’t need to worry about a waterproof solution. However, I have already adapted their solution for a drogue attachment. Now I am bringing the two ideas together.

I had another smaller concern, they have lashed the Low Friction Ring on with 4mm Dyneema and used knots to secure the lashing. Knots are not a good option for Dyneema, they are weak and can slip.

So I have a new design. Rather then keep the existing chainstay positions I am going to move them all slightly outboard to the bulwark. In this photo you can see a couple of shrouds attached to chainplates (circled in red).

Note that the bulwark here does not have the toerail cap fitted (and it still isn’t fitted). The bulwark is part of the joint between the deck and the hull. It is built really strongly and part of the problem we have at present is that the loads from the shrouds are not transferred into the hull but instead can lift the deck which is what has caused cracks (only in one place). Here is the a snippet from an original drawing showing the chainplates but we don’t have a drawing for the ketch rig and the mizzen chainplates are further inward away from the hull. Note that only the main mast cap shrouds (one per side to the top of the main mast) have the stainless steel strip bolted to a bulkhead for much greater strength.

So my new idea is to:


  • Drill 2 holes through the bulwark for each chainstay. They will slope down as they go from the inside and they will not go through to the inside of the boat. I’m thinking 25mm diameter at the moment.
  • On the outside of the hull for each chainstay I will fit a 10mm G10 (outside so no need to use the more expensive for fire-resistant FR4 version) backing plate. This will be attached to the hull with thickened epoxy.
  • Smaller holes will be drilled in the backing plate in line with the centre of the larger holes through the bulwark (large enough for 3 strands of 5mm Dyneema line).
  • I’ll plug the holes in the G10 and fill the holes in the bulwark with thickened epoxy.
  • Then I’ll drill the smaller holes from the outside through the middle of the thickened epoxy.
  • Next I fit a G10 backing plate to the inside of the bulwark with thickened epoxy (this is so the shrouds will clear the edge of the toe rail cap).
  • The holes are drilled from the outside through the inner sheet of G10.
  • The holes are very carefully smoothed, especially the entry/exit points which will be very rounded off (in the direction the load will pull the line)

The Chainplate

To avoid knots and to make for a quicker installation I will have a length of 5mm Dyneema with a locked eye splice at each end (4mm plenty for the Mizzen). Also one generously sized Low Friction Ring (suitable for a 5mm line to go 3x around the ring).

  • On the inside of the deck one eye splice is looped over the low friction ring (a reasonably tight fit but not very critical).
  • The other loop is passed through a hole to the outside, along the backing plate and back in through the other hole.
  • It goes around the ring and back out through the bulkhead then back through the second hole
  • The other eye splice is now looped over the low friction ring which is now held in place by more 3x the strength of an eye spliced 5mm Dyneema Line. That is approximately the same strength as a 12mm Dyneema line (but as our Dyneema Shrouds are sized for stretch rather than strength this is plenty to spare).
  • This Low Friction Ring is now lashed to the bottom of the appropriate shroud to hold the mast up.

If we feel that we can’t get the G10 and thickened epoxy smooth enough to avoid chafe on the lashing we could either line the holes with HDPE as Free Range Sailing did, or fit chafe sleeves to the Dyneema.


Compared to the previous design this solution has a number of advantages:

  • No holes in the deck
  • No waterproofing challenge
  • Even easier to inspect and replace
  • Moves the shroud mounting points slightly outboard which
    • reduces loads as a more favourable angle
    • makes walking past on the side deck easier
    • moves them further from the sails reducing the potential for chafe
  • Less work to fabricate
  • Stronger and no need for any knees to connect the side deck chainstays to the hull.
  • With G10 backing plates epoxied to the hull on the inside and outside (so connected to both hull and deck) with the loads spread widely, the chainstays should be massively stronger.

Plus for anyone needing to re-rig the boat without taking the mast down then the new chainstays can be fully prepared and fitted with the original shrouds in situ.

This is one of the plans I said I was working on the other day.

Using a dyneema pendant as a simple solution

I’m a great fan of simplifying things, even if I’m not always good at it 🙂

So I love this Dyneema Pendant, which you can buy from Mantus (they call it a Snubber Pendant).

Except, that it is so simple that we will make several of our own. We will probably use a home made soft shackle rather than a shackle to attach it to the snubber line (cheaper, tool free and not going to damage the boat).

Three main uses:

  • A tool and metal free attachment of a snubber line to the anchor chain (the snubber line provides some elasticity which stops the boat pulling the anchor out of the seabed when the bow rises on a wave). One that is easy to undo even after it has been used with heavy loads. Using this means that if you need to put out more chain (for example with a dragging anchor or higher than calculated tide) you don’t first have to pull in some chain (making the situation worse) to untie the snubber, just let the snubber drop in the water, use another pendant and snubber line and recover the original later.
  • As demonstrated in the Mantus video to help recover if a sheet gets angled on a sheet winch.
  • Using a similar technique, use it to recover your Jordan Series Drogue. Tie to a bridle line, connect snubber line and lead that to a winch. When you run out of snubber line at the winch then attach another pendant and snubber line to the bridle line as far out as you can reach, then pull that one in. Repeat until you can put the actual Jordan Series Drogue line on the winch.

There are multiple aspects to the simplicity that I love:

  • Untying it after a significant load is so easy. Essential when recovering a Jordan Series Drogue where the loads can be huge. A traditional rolling hitch will probably need to be doubled and even then very hard to untie.
  • Attaching it to the chain with a cow hitch is so easy, much easier than a rolling hitch and no metal chain hook damaging your deck. This is so important as the critical use with an anchor chain will be when it is rough and the bow is plunging up and down.
  • So easy to create and inspect for damage. So providing you have a stock of Dyneema line you can very easily make a replacement at anytime you need it.

As I say I’d probably attach it to the snubber with a soft shackle which avoids needing a tool to attach, and of course no issues with corrosion or electrolysis. My favourite soft shackle technique is this one (much easier to tie than many others and I think stronger than any which do not bury the ends from the knot):

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, but we have a cheap getting us started option using lightish timber struts. Update see 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 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 hav 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.

The top 500mm or so will be above the diagonal struts and 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 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. Lower to the deck and secure.
  • At anchor. Rotate and tilt so the panels are as close to right angles to the sun, adjust to compensate for both the boat and the sun moving.


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!
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.


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)