Boats and Money

We all know that boats use a lot of money. They cost money to buy them, the cost money to store them, and they cost money to repair them.

These costs are not very negotiable. You can take steps to reduce these costs, but they will still cost in the end. The only cost you can take full control of is the cost of upgrading your boat. The boat show is the best example of an adult candy store! All the booths are pretty with shiny gizmos that dazzle and draw you deep into their snare!

The best way to avoid wasting money is to avoid buying stuff that won’t actually work! After three years of cruising full time and an ocean crossing, we have a pretty good understanding of what works and what doesn’t. Watch as we discuss our biggest money wasting purchases for gear that we have made so that you can learn to avoid these traps.

La Mancha in Spain

We travel deep into the heart of Spain where we find an ancient clifftop city named Toledo where we learn about Manchego Cheese and real Toledo Steel Swords.

Not All Dyneema is Created Equal

Dyneema is a wonderful modern fiber that is incredibly light and incredibly strong. It can be used for all sorts of different purposes, ranging from anchoring giant oil rigs, mooring huge cargo ships, mining, logging, and even standing rigging on a sailboat!

The only issue with using Dyneema for your specific application is you need to be informed about “which” Dyneema you want to use. It has been many years since the first generation of Dyneema came to market, and since then it has gone through many evolutions as particular needs were found, and then met.

Saying “I’ll rig my yacht with Dyneema” is the same as saying “I’ll have a dog guard my house”. Are you talking about a Chihuahua, a Pug, or a German Sheppard? Some dogs are better for specific jobs and the same holds true with Dyneema.

As Dyneema products improve, their prices fluctuate. What used to be the latest and greatest comes down in price as the new “best product” takes the high price on the market. This makes it tempting to buy “cheap Dyneema” for your rigging, but it is important to look at what kind you are getting.

An early form of Dyneema is called SK-75. This rope is incredibly strong and lightweight, but it doesn’t do well under a constant load as it will begin to creep (rather heavily).

SK-75 was then replaced by SK-78 which had the same properties as its predecessor but with improved creep resistance. SK-78 was then improved upon even further with an entirely new generation of material called DM-20.

Naturally, SK-75 is very inexpensive, SK-78 is a little more expensive, and DM-20 fetches a higher price. All three fibers are single braid 12-strand rope, so why can’t you use them interchangeably?

This will all become apparent when the three different types of Dyneema are subjected to the same load at the same temperature.

The three fibers were subjected to the force of 300 MPa at 30*C and the creep was measured.

• SK-75 creeped 0.02% per day

• SK-78 creeped 0.006% per day

• DM-20 creeped 0.00007% per day

The percentages seem small, but on a boat, the “per day” is indefinite! Rigging is always under a load and every year is 365 days. In one year SK-75 would creep 7.5%. If your stay is 20m long, you are talking about it creeping an additional 1.5m (4.9 feet)!

Steel standing rigging has an expected lifespan of 10 years, that’s 3650 days. That would be 73% creep! This sounds pretty extreme but the stay would have failed from a creep rupture long before ever reaching that point, meaning it would fail long before the 10 year mark. SK-75 tends to fail at around 50% creep, which means you could expect it to fail in about 6 years.

SK-78 creeps significantly less than SK-75, about 3 times less actually. This means that it will hold your rigging and avoid creeping out of control before your eyes! Over 10 years of that grueling experiment, you can expect the a stay to creep 21.9%. This is significantly less than with the older generation of SK-75 fibers and really good news to someone who uses this as their standing rigging. SK-78 tends to rupture from creep at around 30% creep elongation, meaning that SK-78 would outlast steel rigging (if a yacht were the torture chamber that was this experiment). If your rigging lived in that torture chamber, it would be expected to fail at around day 5000, or 13.7 years into the experiment!

Naturally, one can expect that DM-20 raises the stakes for what is considered ideal The creep resistance improvement from SK-78 to DM-20 is 85.7x better (from 0.006% per day to 0.00007% per day)! After 10 years in the torture chamber, the stay would have creeped a mere 0.255%. That is practically nothing! In our imaginary 20m stay in this torture chamber, the stay would only creep 0.05m (1.96 inches) over 10 years! Compare that the the 1.5m of creep from SK-75 in the first year!

While SK-75 tends to rupture from creep at around 50% in torture tests and SK-78 tends to rupture around 30% from creep elongation, none of the tests that I have seen has managed to cause DM-20 to fail from creep. 30*C is wonderful for accelerating the flaws of creep, yet tests at 70*C (which manage to rupture SK-75 and SK-78 in a few days) failed to cause DM-20 to fail. After 6 months, the test was ended without a creep failure in DM-20.

While you can find “cheap” Dyneema to rig your yacht, it is worth the extra expense to buy the right kind of Dyneema for your yacht. Creep will not be a concern and you will be able to rest and relax knowing that your rigging is incredibly strong and secure, even against creep!

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!