Creep vs Thermal Expansion

One of the biggest concerns about synthetic standing rigging is creep. There are a lot of misconceptions that any stretch experienced in the rigging is creep, and therefore creep is uncontrollable and inevitable!

Creep is permanent elongation of the fibers due to load, time, and temperature. The higher the load and the higher the temperature, the more creep can occur. When Dyneema is used for standing rigging, the time is infinite and therefore not part of the concerned equation as there is no ability to “give it a break”.

To prevent creep, all you need to do is size the stay accordingly so that the load the stay is subjected to is very low and therefore the “load” is low and the temperature is ambient temperatures, therefore also under control.

Creep tests are “expedited” by setting the temperature to 30*C (86*F) as a minimum. Accelerated tests are performed at 70*C (158*F)! Hot summer days are the only times when the temperature gets out of hand and above the 30*C mark.

While creep is accountable and controllable, Thermal Expansion is a different story. Thermal Expansion is the phenomenon where Dyneema will expand as it cools and contract as it heats. This is not creep, this is merely thermal expansion.

In winter, when synthetic rigging goes slack and is “stretched”, this is not creep, this is simply winter stretch. Creep would remain long and slack, but since it’s not creep, the stay will contract and go back to size come Spring. Thermal Expansion is something that you need to deal with if you have synthetic rigging, but it’s really not that bad.

My rigging is tuned to 80*F. This means that it is a smidge tighter on the hottest of hot days, and well tuned all the way down to 60*F. Below 60*F, we simply keep the sails to only as high as the spreaders to keep the loads lower. If it’s too cold to put up sails, it’s also too cold for us to go sailing and stand outside in the wind! Hence we take that day to relax and avoid the frigid weather by staying inside next to the heater.

This is What Dead Rigging Looks Like

How do you know if your standing rigging is dead? There are many tiny tells that can indicate the level of health of your rigging and most of them are microscopic!

Thankfully this one tell is very small but not microscopic! (Though it is very small)

Do you see how the scum line at the base of the stay has slipped up just above the compression fitting? The scum line formed from years and years of gunk collecting the bottom of the stay at the top of the compression fitting (or swage fitting). The reason the scum line is raised is because the stay has slipped up and brought all the debris up with it!

The fact that the stay has slipped out of the fitting indicates that the fitting is failing and the stay is dead. Sailing on this rigging will lead to catastrophic failure when the stay slips out of the fitting completely!

Aside from corrosion issues, cracks, broken wires, or abrasion, which are all rather difficult to stop, this indication is rather easy to see and tells you right off that your rigging needs replacing!

Going up the Mast!

Climbing the mast is a necessary part of operating a sailboat. Whether you are going up to inspect, or going up to repair something, at some point you will need to go up the mast.

The normal method to climb a mast is to have someone winch you up the mast. The problem with this method is that you rely on someone else to hoist you up and even worse you rely on their skill to safely bring you back down to the deck.

Having a gantline setup allows you to pull yourself up and more importantly it allows you to bring yourself back down to the deck. The gantline is simple to setup by attaching a block to a halyard and hoisting it up the mast (with the gantline run through the block, otherwise you just sent your halyard up the mast with no way to retrieve it). The other block is attached to your bosun chain and up you go!

Depending how strong you are and how much you weigh, you can alter the amount of mechanical advantage in the system. Remember, pulleys are a simple machine!

Pulling all of your weight up a mast is very hard work! If you setup a 2:1 purchase system, you only need to pull up 1/2 your weight. If you setup a 3:1 purchase system, you only need to pull up 1/3 of your weight. If you setup a 4:1 purchase system, you only need to pull up 1/4 of your weight.

This sounds great, but there is always a catch! The more you reduce the amount of weight you need to raise, the more you increase the amount of line you need to pull. For a 2:1, you pull 1/2 your weight but you also pull 2x the amount of line! For a 4:1, you pull 1/4 of your weight and 4x the amount of line!

If you are climbing a 50 foot mast, this is the difference between pulling half your weight 100 feet or a quarter of your weight 200 feet! At some point, you will just get tired from the repetition and not from the resistance.

I find that it is best with a 3:1 or 4:1 purchase system. If I’m feeling strong, I will do a 3:1 and get up the mast quickly. If my arms are really tired, I will use a 4:1 even though I will have to pull a lot more line!

It also helps to have an extra person (if they are available) around to pull on the tail and do the work for you so that you can rest on your way up that way you are calm and relaxed up there instead of winded and tired. Best of all, when it is time to come down, you can control your rate of decent.

Attaching Synthetic Standing Rigging to Your Mast

Synthetic standing rigging sounds amazing. It’s lighter, stronger, and easier to install than steel rigging; but how do you attach these stays to your mast?

Steel rigging ends in a compression fitting or swage fittings which grips the end of the cable and attaches it to the mast. Synthetic stays can’t be squeezed into a swage fitting or pinched by compression fittings. So how do you attach your new synthetic stay to the spar?

Easy! Instead of a compression type fitting that grips the bitter end of the stay, all you need to do is create an eye splice into the end of the stay. The eye splice simply slips over the clevis pin and attaches to the stay to the spar!

While steel rigging ends in fancy mechanical fittings that need to be purchased, synthetic standing rigging ends in an eye splice which is easy to do yourself!

Synthetic rigging is very easy to make and very easy to install.

The Magical World Aloft

Being up a mast might not bother some and might terrify others. The truth is being up there is a great way to clear your mind.

When you are aloft, you have no distractions, no pressing deadlines, no nagging co-workers. It’s just you in your own little world high above the rest. You get a great view of the entire area where you are and you can see far off into the distance.

I personally do not look forward to going up the mast, but while I’m up there, I always feel so relaxed. Everything stops and the whole world takes on a new appearance. It really is a magical place to be.