Twin Headstays

Source: http://www.setsail.com/twin-headstays-like-we-did-it-in-the-olden-days/

Why don't you see any yachts with twin headstays? They seem like a great idea.

When sailing downwind, you can easily set two headsails poled out on each side giving you a giant balloon of a headsail with optimum control. Each sail will ride on its own stay, so there is no issue with lowering one of the sails should you decide to change course from a run.

You can also carry two headsails rigged on the stays for varying conditions. Imagine the wonders of having a 150% genoa on the port headstay and an 80% jib on the starboard headstay. If the winds are light, you can hoist the genoa. Should the weather change during your voyage for the worse, all you need to do is lower the genoa and hoist the jib. There are no sailbags to lug around or hanks to mess with, as the sails live on deck attached to their own stay.

From a security and redundancy perspective, twin headstays will be perfect! Imagine if you are sailing along with a single headstay and the headstay parts, the mast will become unsupported and risks falling aft and over. Some yachts have two backstays so that if one breaks, the other one will hold the mast up; why not have two headstays as well? If one headstay breaks, the other headstay will take up the slack and keep the mast up in the air where it belongs.

You might be wondering why twin headstays never really caught on, being how they make downwind sailing a breeze and offer the added security of a redundant headstay. The reason is because yachts do more than just sail downwind and twin headstays have some fundamental problems that led to their demise.

When it comes to sailing on a run, there is nothing better than headsails set wing on wing. They will create so much lee helm that the yacht will sail itself as you ride on a downwind sleigh ride. The moment you turn to windward, the twin headstays will work against you. Proper headstay tension is needed to keep the luff tight so that the yacht can point to windward efficiently.

Sailors quickly noted that the headsails would work on one tack but not the other, meaning that sometimes they could work to windward and othertimes, the headstay in use would be slack while the other headstay had all the tension. This problem is due to the geometric setup of the twin headstays. 

The headstays were setup side by side, sitting next to the stem. When the mast is loaded by wind pressure on the sails, it will bend to leeward slightly. As it bends to leeward, the leeward headstay will go slack as the masthead moves to leeward and falls right behind the leeward headstay. At the same time, the masthead will fall away from the windward headstay which will increase the tension on the windward headstay as it takes all the force.

A twin headstay setup would work properly if you switched headsails as you tack, always using the headsail on the windward stay. This adds a lot of work, which will not be done because sailors went through the trouble of rigging twin headstays for the convenience, not for extra labor!

Since the leeward headstay goes slack, this must mean that the leeward headstay doesn't have enough tension. This led sailors to increase their headstay tensions to attempt to rectify this problem. Two really tight headstays made matters worse as the twin backstays were opposing this force and led to unnecessarily high compression forces on the mast. 

The other problem with twin headstays is the hanks can get hooked on the other stay if the headstays are mounted too close to each other. They typically need 6 to 8 inches of clearance to avoid any interaction between the hanks on a sagging headstay and the other headstay. Aside from the hanks interfering with each other, you run the issues of the added windage from the extra stay. This problem is compounded should the owner try to rig twin furling headsails. The furled up massive headsail will cause so much wind resistance and turbulance that it will rob the working sail of its wind and efficiency.

If you ignore the downfalls of a twin headstay setup simply for the benefit of the structural redundancy, you will still be disheartened. Having two headstays for the sake of redundancy means that you assume that the headstay is going to break. If you feel this way, you should also have two backstays, and multiple shrouds, just in case the other stays break as well. Soon enough, your mast will look like a Christmas Tree with all the shrouds surrounding it.

Having one well maintained and properly sized headstay will provide you all the tension you need on any tack without all the problems associated with having side by side headstays. If you want to have the ability to setup two headsails with ease, you should consider a cutter rig, or setting up a solent instead.

Cutters and solent rigs have two headstays set in a line, where the stays still attach at the centerline of the stem and will not rob each other of tension, nor interfere with the performance of one another. The only problem with this setup is the small slot between the two stays will make tacking a large headsail troublesome. 

With everything on a sailboat, there is always a give and take. If you plan to only sail downwind, a twin headstay setup would work well for you. If you plan on sailing at any other point of sail and still want multiple headsails permanently rigged, do consider a cutter or a solent setup.

Sizing for Creep

The question of what size should my synthetic stay be to replace the metal stay comes up a lot. As always, there are two methods to figure this one out. 

The first is to calculate your RM30. RM30 is the force that is required to heel the boat over 30 degrees. There are many factors that play into this number, but they will give you a good idea of the loads your shrouds will experience while sailing heeled over at 30 degrees. Once again, there are two ways to calculate this value, one is via an actual test performed on the boat while in the water, the other via mathematical equations. 

With this number in hand, you can safely calculate the size of your standing rigging knowing the loads that it will be subjected to.

The other method is to base it off of the standing rigging that the boat was originally designed to have. Steel standing rigging is sized so that the maximum amount of tension applied to it is 20% of its breaking strength. While your standing rigging should never be set this tight, this is the safety margin in steel rigging. 

If you have 1/4 inch 1x19 316 stainless steel standing rigging and wish to know what size your synthetic stays should be, simply do some simple calculations. 

1/4 inch 1x19 has a breaking strength of around 7600 pounds. 
20% of 7600 is 1520 pounds

Synthetic standing rigging is sized based on creep rather than breaking strength. Synthetic standing rigging will creep less if it is under less static load. Keeping the static load below 15% will keep creep down. If the load is less than 10% of the total strength of the dyneema, creep will be significantly less. 

With our example of 1/4 inch 1x19 SS wire with a 20% load of 1520 pounds, we can safely assume that using 6mm New England Ropes STS-HSR with a breaking strength of 12,400 pounds would be a safe choice. 1520 pounds of static load would be 12.3% of its total strength, keeping the creep to a safe amount. Sizing up to the next size would reduce creep considerably but also increase windage.

7mm New England Ropes STS-HSR with its breaking strength of 18,700 would be loaded at a mere 8.1%. Creep would be significantly lower with a slight increase in windage. 

In the opposite direction, 5mm New England Ropes STS-HSR with its breaking strength of 9,300 pounds would be loaded at 16.3% of its breaking strength. While windage would be significantly less, the creep would be considerably higher than with the other two options. 

Additional windage is from thicker stays is not the end of the world, though they rope itself is more costly. Choosing a size that offers you the resistance to creep and windage you are comfortable with depends on your ability and willingness to tune the rigging. If you choose a very small stay that will creep, you will need to tune it more often. If you choose a thicker stay, it will cost more and be more windage, but it will hardly creep at all.

Cost of Conversion

One of the first questions I am asked by clients is: "How much will it cost to convert to synthetic standing rigging?"

The short answer is: Around the same price as 1x19 SS rigging if you have me do all the work, and much cheaper than 1x19 SS rigging if you do the work yourself.

The cost of materials is significantly cheaper than stainless steel, mostly due to the fact that stainless steel is made of metals that need to be mined and processed. Synthetic standing rigging is made out of UHMWPE (Ultra High Molecular Weight Poly Ethylene), otherwise known as plastic. Plastics are cheap and as manufacturing processes and techniques improve, costs go down!

Since the costs of materials are so much cheaper, the total cost to re-rig your yacht is also cheaper. Turnbuckles cost around $100 each where the materials to make a deadeye cost around $24 each. The fittings at the end of stainless stays cost between $100 to $400 each, where the fittings at the end of synthetic stays cost around $1 to $12 each; significantly lowering the cost to re-rig.

The major difference is the cost of labor. Splices are more labor intensive to perform than a swage or compression fitting, and tensioning standing rigging with deadeyes is a lot more labor intensive than with conventional turnbuckles. The cost of labor is significantly higher than with steel rigging which offsets the cheaper material costs to give a similar end price.

If you are the type of person who will do it yourself, you can save a significant amount of money by doing the conversion to synthetic standing rigging yourself. If you need to pay someone to do it, the costs will be around the same in the end.

Using the Islander 36, which fits the mold of an average 36 foot cruising yacht with a double spreader rig, the material costs were:

• $861.49 for the stays
• $64.60 for the deadeyes
• $379.62 for the lashings
• $156.84 for the thimbles

At this point, the materials only cost $1,462.55

If your mast has regular tangs that can accept a clevis pin, you are set! If your mast has t-ball fittings or some other connector, the costs will go up as you need to include the costs of adapters into the cost of conversion.

• $1,303.76 for 8 T-ball fittings and toggles to connect to the synthetic stays

Now the material costs have nearly doubled to $2,766.31. This is significantly less expensive than if you were to re-rig with stainless steel, as long as you do all the work yourself and don't need to pay anyone for labor.

Fabrication of a backstay and eight shrouds (Cap, Intermediate, Forward and Aft Lowers [Port & Starboard]) and all 9 deadeyes took me 30.14 hours on the Islander 36. This number doesn't fluctuate very much because the length of the stay doesn't add considerable time to the job. I work at the ends of the stays and the space in between doesn't affect my working time. On average, it takes me around 32 hours to fabricate the rigging for a double spreader sailboat. Single spreader sailboats are quicker because they have two stays fewer and only need 2 areas serviced instead of 6 with a double spreader rig. 

Being how I currently charge $105 per hour for labor, 32 hours of labor adds $3,360 to the cost of re-rigging.

In the case of the Islander 36,

• The material cost was $2,766.31
• The labor cost was $3,164.70

This brings the cost to re-rig the Islander 36 up to $5,931.01. This number is significantly cheaper than the cost to re-rig a 36 foot yacht with stainless steel, but the job is not finished yet. At this point, the new rigging is sitting in a box awaiting installation. If you install and setup the rigging yourself, this would be the final number in the cost to re-rig. If you don't want to do it yourself, you will need to pay someone to continue doing the work.

Average installation and setup takes around 30 hours (at $105 per hour), which would add another $3,105 to the bill, bumping the cost to re-rig up to $8,010 for an average re-rig.

This number is reached by assuming that the average cost for materials is around $1,500, 32 hours to fabricate the rigging, and 30 hours to install the rigging. As you can see, there is a significant difference between the $1,500 price point of doing it yourself and the $8,010 price point of paying to have it done professionally.

$8,010 is an average amount to pay to have the standing rigging replaced with 1x19 stainless steel on a 36 foot yacht. The prices are currently around the same level, but the savings in weight are quite great! Steel is very heavy and dyneema is very light, 1/4 inch 1x19 SS weighs 0.15 pounds per foot and 6mm dyneema weighs 0.017 pounds per foot. In this example, dyneema is 8.8 times lighter in weight than steel!

Looking back at our example with the Islander 36, the final cost of materials was $3,454.56. I did the fabrication and the owner did the installation, followed by me doing the setup of the standing rigging. Lastly, I climbed the mast to inspect everything and seized the spreaders in their correct position. The total labor time was 49.74 hours and the final cost to re-rig was $8,677.26. 

The owner showed me other estimates he had received which were right around this number as well for 1x19 SS standing rigging. Once again, the cost of materials is significantly cheaper, it's the cost of labor that brings the price of re-rigging right up to be comparable with that of steel rigging. 

If you need to pay the same amount to re-rig your yacht, why would you choose a material that is heavier and prone to corrosion over a material that is so much lighter and immune to corrosion?

Islander 36 Conversion: Seizing the Spreader Tips

Seizing the spreaders is a simple concept: you tie a knot that will hold the shrouds in the tip of the spreader and prevent movement of the spreader on the shrouds!

This may sound easy enough, but each spreader tip is different, and your boat may look different from this tip. You need to look at your spreader tip and evaluate how you can attach the seizing line to the shroud to the tip without damaging any of the components. This spreader tip had holes drilled through next to the shallow notches to hold mousing wire. Mousing wire will prevent the shroud from jumping out of the notch but it won't prevent movement on the spreader tip. 

By tying the spreader tip up with dyneema and taking advantage of the holes in the spreader tip, it is possible to hold the shrouds in place and prevent movement at the spreader tip. The basics are to tie the spreader tip to the shroud and then to the shroud, this will hold the shroud in the notch and keep anything from moving at the same time.

You can easily visualize the damage that movement of the spreader tip can cause by observing the severe chafe in the lower portion of this photo. The spreader tip rested there during the initial setup of the synthetic standing rigging. Once the major adjustments were taken care of, I climbed the mast and positioned the spreader so that it would bisect the angle to the shrouds. This results in a slight up-sweep of the spreader (which places the drain hole at the lowest point to keep water from collecting in the spreaders if they are mounted correctly). The spreader was tapped and pushed into its correct place, several inches higher than where it was originally sitting and then seized in that position.

By removing any movement between the spreader tip and the shrouds, it is possible to reduce the chafe that will occur to the shrouds. Any damage that does occur between the shrouds and the spreaders will be limited to the serviced area. This sacrificial layer will protect the structural stay within from chafe while still being easy to repair if the chafe ever becomes too severe.

Broken Spreader

While aloft for the final inspection, I noticed that the lower starboard spreader was in serious trouble!

First, the spreader was mounted upside down. The trailing edge of the spreader was facing forward and the forward edge of the spreader was trailing. The distinction in directions is only evident due to the air foil shape of the spreader. Round and square spreaders create a lot of drag and wind resistance, air foils create significantly less drag. An air foil creates less drag in a specific direction, and slightly more drag if it is set backwards (though still much less than a round or square air foil). Being how this is not a racing yacht, a slight increase in drag is not going to be detrimental to the sailing performance of a cruising yacht.

The reason that the direction of the spreader is so important is due to the drain hole for water in the spreader. The spreader has a drain hole near the mast on the bottom side. If the spreader is mounted with the trailing edge leading, the drain hole will now be on the top side of the spreader and instead of a drain, it would act as a water fill hole. Water inside a spreader will cause more weight aloft but more catastrophically, it will hold water that can turn into ice during the winter. The expansion of the freezing water inside will place great and unnecessary stresses on the aluminum air foil spreader and lead to its eventual and apparent failure.

The other factor that came into play with this particular spreader is the location of the spinnaker halyard and flag halyards. Both of these halyards (which look like they haven't been moved in 30 years) were rubbing on the front of the spreader. While the lines themselves were not significantly chafed, they did grind away at the soft aluminum of the spreader. The lines are full of dirt which acts like sand paper rubbing on the thin trailing edge of the spreader. If you have spare halyards installed on your mast, be sure that they are not contacting anything on their run. Over the years, either the halyard or the rig will become chafed and lead to costly repairs in the future.

The combination of the thinner metal of the trailing edge of the spreader being ground away by the halyards and the ice expansion inside the spreader may have led to the opening of the spreader.

Upon this discovery, the shrouds were relaxed and the spreader unbolted. It was then taken to a metal shop to have new aluminum welded onto the trailing edge and then ground into shape. The spreader was then painted and reinstalled the next day! With the repaired spreader in place, it is time to position the spreaders and seize the tips.