July 8, 2016-Get That Wire Off My Boat!
Note to our readers: This is a story about a maintenance project. It isn't a sailing story or otherwise an entertainment piece. Just a warning, it might be a bit dull unless you just would rather be messing about in boats than doing anything else in the world.
wingssail images-fredrick roswold
Coil of New Dyneema Rope
Why are we talking about wire?
When Wings was built there were few rope options considered strong enough for the loads the boat often developed. Running rigging like sheets and halyards had to be strong and Dacron ropes that were strong enough were huge. Sheets and guys in Dacron had to be bigger around than a man’s thumb. When Kevlar rope came out it was smaller in diameter and stronger than dacron but it had a reputation for being brittle if flexed too much. In fact when we first tried Kevlar rope for jib sheets the Kevlar cores broke into short pieces and the lines failed. I remember cutting off a Kevlar line in the early 90’s and having short bits of the Kevlar core fall out on the deck. So, on Wings and similar boats, wire rope was used for most of the lines. Wire was strong and didn’t stretch. We had wire halyards, wire spinnaker guys, wire running backstays, and even wire jib sheets, all made out of ¼” stainless steel and all mated to Dacron rope tails for easier handling and to protect the winches. Let me tell you, working the foredeck with wire sheets flailing around was scary. Wire also often gets broken strands on it which poke out and which are called “meat hooks” for good reason. Not only do meat hooks terrorize the crew, but they can, and have, sliced sails like razor blades.
Everyone hated the wire.
Keeping up with technology
Not only that, but we wanted to keep Wings up to date so when more new rope types became available we wanted to avail ourselves to those new technologies. When the flexing and breaking problems of Kevlar seemed to be solved we started to buy these new stronger, lighter, ropes. By now we have switched out most of our wire running rigging to Spectra, Kevlar and Technora rope including sheets, guys and running backstays.
But some wire still remained
But we still used, for our halyards, up to this day, stainless steel wire with rope tails. For halyards the replacement technology was expensive and for that and other reasons, we delayed making a change. The urge to keep up with technology remained. Finally our wire halyards have gotten to the point where they really need changing and we either need to make new ones with wire or switch to the new ropes. (We also, by the way, have wire on the lifelines, check stays, and upper runner segments. These also need replacing.)
Selection Problems for rope
We decided to get the wire off of the boat, starting with the halyards. We wanted to use Dyneema, one of the newest ropes. Dyneema is an ultra high modulus polyethylene which is much stronger than the same size stainless steel wire. However, it is expensive. It is also a bit of overkill. The Dyneema ropes big enough for easy handling by the crew, (1/2”), had cores over 3/8” in diameter too big for our mast head sheaves and they were strong enough the lift the whole boat! Smaller Dyneema ropes were a better match for the loads involved but they would be hard to hold onto and they would slip through the line stopper clutches. Finally, buying enough of the lastest dyneema cored rope, of any size, to make a halyard would cost around $500, and we needed five of them (including the pole lift). We didn’t need and could not afford that these Dyneema lines.
What we decided to try
Our solution was to use very small diameter Dyneema for the parts of the halyard which goes over the sheaves and bear the loads and to use good sized rope where people would be handling it and where the stoppers needed to work. This is called “stripping” the cover off and we could do it for a major portion of each halyard. And we decided to go for the smallest diameter Dyneema that would carry the loads. The “brilliant” part of our solution was to use the old covers (the outside) from our existing halyards. We would replace the wire and the core (the inside) of our old halyards with smaller and cheaper Dyneema. I say “brilliant” but maybe it wasn’t, really, because we didn’t think it all the way through. It wasn’t so brilliant when all the facts were known. Sure, this would be a very up-to-date and a high tech solution and the Dyneema would cost us only about $140 per halyard, saving heaps of money, but the down side was that it would take a lot of work to insert the new Dyneema into the old covers. Then there was the issue of size. The Dyneema was smaller than the old Dacron core and when we finished making a new line with the Dyneema we would have a line which was still too small to easily handle and too small for our rope clutches. Ouch again! So then we decided to get in deeper. We thought of inserting another smaller rope inside the Dyneema prior to putting that into the covers. This would provide the bulk to make the finished halyard the right size and still use the small Dyneema core we wanted. It would solve all our problems (Ha Ha!) but was double the work and in fact we didn’t even know how to do it or if it could even be done. On the first two tries it turned out to be impossible.
But we persisted.
wingssail images-judy jensen
Fred "Milking" the cover over the core
How we did it
Finally we developed a technique that consisted of the following steps:
1. We took down the old halyards and pulled out the wire and rope cores, leaving a hollow cover.
2. We cut a 130’ length of Dyneema (1/4” diameter) to serve as the strength member of the new halyard, allowing some extra length because it would become shorter when we added the filler inside it to bulk it up.
3. We cut a length of small stuff (we used 4mm Dacron) to serve as a bulker (filler) inside the Dyneema.
4. We threaded a light string through the inside of the Dyneema (only the covered portion, not where it would have the cover stripped off). The whole halyard is 130’ in length but the covered part would only be 70 ft in length, so we put the string inside the 70’ foot section of Dyneema which would eventually be inside the cover. This was the most time consuming job. After we finally developed a method which worked it still took over an hour to do and that doesn’t count the two days it took to figure out how to do it. (We pushed a length of antenna wire with a round ball on the end of it and a string tied on the other end into the Dyneema core and worked it all the way down the length of the Dyneema core until we had the string all the way through.)
5. We pulled the 4mm filler into the Dyneema with the string and tying the string to the Dyneema involved another trick, a special streamlined knot (see Photo)
6. Finally, we pulled the whole Dyneema and filler package into the cover with another tricky knot.
7. To finish we put in some splices to bury the cover into the core where it ends and put eyes in both ends and put the shackle on before putting it back into the mast.
The pulling steps (5 & 6) were tough work. We had the whole package laid out on the dock (it took over 210 feet of dock space to lay out a length of Dyneema, a length of bulker, and a cover) and we wore leather gloves to “milk” one line inside of another, walking up and down the dock, pulling the lines, over and over. It did however produce a very cool halyard, which is light and strong, and saved us about $300 each. In fact it was satisfying work. We’ve finished 4, they look great, and we are just waiting for the delivery of some more Dyneema to do the last one.
wingssail images-fredrick roswold
The shackle on the new Blue Halyard
Our next “get the wire off” project will be to replace the lifelines, the check stays and finally the upper running backstay segments with Dyneema. There won’t be any need for covers or “milking” lines inside each other but I’m sure there will be snags in those projects too, but I know we’ll get through it. Then we will have all that nasty old wire off the boat.
Click here for more photos and notes on this project.
Fred & Judy, SV Wings, La Cruz Huancaxtle
Labels: boat work