by Steve Dillen
On the May long weekend, I did what I considered to be the unthinkable and broke a winch cable on my M6000 rear winch. I knew that the cable was tired and had been abused, but I never considered that pulling my Ranger out of a cross ditch that those short-wheelbased guys talked me into going through would be enough to snap it.
So, clearly it was time to do something! Having spent a fair amount of time sailing and following some of the technology advancements in synthetic ropes available for the marine industry, I started to look at rope options. I figure that if these ropes can stand up to the stresses of racing around the world and through the southern ocean, they have to be able to stand up to the abuse of wheeling.
The characteristics of the rope that I was most concerned about are:
- Stretch. Stretch in a winch line is a killer. This stretch, coupled with the weight of the line is what results in the deadly whip-back that we're all so afraid of. If the line doesn't stretch, it can't have stored energy…and therefore should fall flat on the ground when it breaks.
- Creep. Creep is the term which describes permanent elongation of the rope under a load. This is permanent stretch, but without the ability to "contract". This factor isn't really applicable in the loads applied when winching, but is certainly something the manufacturers are concerned with.
- Breaking strength. This is key. My comparison point is wire rope, which is rated at 9800 lbs for 3/8" line.
- Diameter. The smaller the diameter, the more line I can fit on my winch. Since my winches are an M6000 and a Milemarker 9000, I wanted to stay with a 5/16" line if possible.
The fibers in use in high strength synthetic ropes are generally as follows:
- Kevlar - Kevlar is one of the first high strength materials, however it degrades quickly from UV exposure and does not stand up well to abrasion. Also, repeated flexing results in the Kevlar fibers effectively cutting each other which further reduces the strength of the rope. 5/16" is typically rated at around 9500 lbs.
- Technora - This product has no creep and very low stretch. Stretch is rated as very low, creep is very low, and 5/16" line is rated at around 13,000 lbs. Currently, these products do not show the resistance to abrasion that the spectra family of lines do.
- Vectran - Vectran has the high strength and extremely low stretch and creep. It does not have good flex/bend fatigue resistance. 5/16" line is rated at about 11,600 lbs.
- Dyneema/Spectra/etc. These ropes have very high strength and low stretch. They are very susceptible to heat degradation, however are quite abrasion resistant. 5/16" lines rate at about 9500 lbs, and the newest products in this category rate in the 13,000 lb area.
Based on these characteristics and the proven history of synthetic fibers, I started to look at the different manufacturers to select an appropriate product. Samson ropes manufactures their Amsteel Blue product specifically for the utility/winching industry. This line has a integrated urethane UV production coating and has very good flex fatigue and wear resistance characteristics, and IT FLOATS. Samson rates this line with a minimum breaking strength of 12,300 lbs (for a spliced segment of the rope) and claims an average strength of 13,700 lbs. Most of the web retailers of replacement synthetic winch lines also carry this product, so I felt that I had some independent validation of my selection and ordered a 600' spool of this line. Because I sometimes splice double braid line on the boat, I also picked up a set of splicing fids and a bunch of thimbles for the eyes.
The splicing kit (fids, thimbles, etc).
The first thing I noticed when I picked up the spool is how light this stuff is. A 120' length weighs about 3 lbs. Other than that, this stuff looks…well…like ordinary rope. I downloaded the very clearly written splicing instructions from Samson's web page and proceeded to cut the line into segments for installation.
Installation and splicing:
Following the instructional PDF documents posted on Samson's web site, I was able to make my first eye splice in about 5 minutes. I'm using an actual fid, however a fid for rope is 21 times the rope's diameter in length - or about 6 and a half inches for 5/16" line. For this line, a bic pen is almost the perfect size.
To eye splice the line:
- Place a Mark #1 one fid length from the end of the rope. Notice that a 5/16" fid is almost the same size as a bic pen - about 6.5" long.
- Place a second mark two fid lengths beyond mark 1. The rope will be "buried" up to this point when the splice is complete.
- Place a third mark to indicate the size of eye you want. The rope between mark 2 and mark 3 will be exposed at the end of the splice to become that eye.
- Place a 4th mark 4 fid lengths beyond mark number 3. The tail of the rope will be buried into the core up to this mark.
- Taper the end of the rope by cutting half of the thread fibers. This rope is made up of 12 strands in a "herringbone pattern". To taper the end, from mark one, working towards the end of the rope, skip the first pair of strands and mark the second pair. Skip the third and mark the 4th. Skip the fifth and mark the sixth.
- These marked pairs (six strands) are cut and removed from the line to produce a taper to half the original rope diameter.
- This is the "tough" part. Using the fid as a "giant needle, insert the end of the rope into the core at mark 3 and feed it all the way through the core until it comes out at mark 4. The splicing set I purchased came with a "pusher" to help, however this line is easy enough to work with that a bic pen will work just fine.
- When done, mark 2 and 3 should line up, resulting in an eye of the exact size you need.
- Cut the tail exposed at mark 4 at an angle to complete a nice taper.
- "Milk" the line into the core while tightening the eye around your thimble.The end will disappear into the core resulting in a complete eye splice.
Although the splice at this point provides all of the strength of the rope, it can work loose when it's not under load. To prevent this, use some twine and sew the line at the throat of the eye to bind it into place. The PDF available from Samson's site shows a good method for doing this.
This splice can be used on both new and used rope and is claimed to provide about 90% of the strength of unspliced rope. Samson rates their product with a splice, therefore the spliced eye should provide the full 12,000+ pounds of strength.
Because this line is so expensive (it's generally about three times the price of wire rope) and is susceptible to abrasion, most sites recommend some kind of an abrasion shield for the line. I decided to use some very inexpensive ½" hollow braid polypropylene rope as a slidable abrasion shield. Twenty feet of this line (in two 10' segments) should provide the flexibility to protect the Amsteel blue in most winching situations, and will double as a cover for the line when on the drum. Of course, there is always the potential for cutting this rope. Instructions are available (again from Samson's web site) for performing an end-to-end splice….which again retains the full rated strength of the rope. In short, an end-for-end splice is done the same way as an eye splice - bury 3 fid lengths of the end of each line into the core of the other. The crossover point will be double the original rope diameter - and each side of the splice will taper back to the original diameter.
Installation on the winch:
Most lay-down style winches that I've seen use a single screw to secure the end of the line to the drum. Usually the winch rope is fitted with a crimp-on electrical terminal. I decided that I'd prefer to have a more "reliable" attachment, so I installed an eye-splice in the rope and made a "slip/noose" attachment to the drum.
This rope is very slippery - I found that it takes a LOT of wraps on the drum before friction will hold the line in place. With six wraps, I am just able to put hand-tension on the rope when spooling onto the drum. I wind the poly "abrasion shield" onto the drum last so it will protects the exposed portion of the rope from chafe.
Observations so far:
Over the last month, I've only used my winches for utility purposes (pulling stumps out of a friend's yard, pulling deadfall off a trail, etc.) but have not noticed any loosening of the splices.
- The first thing I've notice when using this winch line is how easy it is to drag out. There are no teeth waiting to bite you and absolutely no tendency to create a rats nest if you coil the line in your hand. Pulling 80' of line out and uncoiling it as you walk to an anchor point is absolutely no problem. If you're the kind of person who likes mud, there's also the advantage of being able to throw the line across deeper sections of the trail. The thing is, this stuff is rope…and is as easy to handle as any other rope.
- Strength…this line is rated at least 25% stronger than equivalent size wire rope. Samson provides a guide for examining the rope to determine when it's at its end-of-life.
- It floats…Ok, maybe this is a novelty thing, but I like things that float!
- Field repairable…when I broke my wire rope, I had no wire clips with me, as a result I had no option but to wind the broken cable up and put the winch away. A splice (either eye or end-to-end) in synthetic rope retains the full rated strength of the line and can be done in
- I did find that if the line is not VERY TIGHTLY wound on the drum, it's slippery enough that when under load it'll "cut" its way through the wraps which can make unspooling more difficult. I've had to cleat the line off and power out in order to clear the overrides on many occasions.
- Abrasion can be a problem…if you like to winch around rock faces, I'd certainly not recommend this line.
- Heat…This rope starts to degrade at 150 degrees F and melts at 300 degrees F. One touch to a exhaust pipe will melt the line in two. Friction can also generate enough heat to destroy the rope. There has been some concern that planetary winches may generate a lot of heat in the drum if they are abused. I did some testing on my Warn M6000 and found that with my normal usage pattern there was insignificant heat build up. This may be a factor for others and I'd recommend giving your winch a complete workout then unspooling your cable and checking the drum temperature before switching to synthetic rope. Many sites are selling rope that has a technora segment end-to-end spliced to spectra, the idea being that the Technora will withstand the heat of the winch drum while the Spectra will stand up better to the abrasion abuse.
- Cost…this rope is about 3 times the price of wire rope. In Vancouver, I was able to find a number of suppliers retailing in the $2.00 per foot neighborhood.
The cost and other disadvantages perfectly acceptable to me when I consider the single most important benefit of using synthetic line. This stuff is MUCH safer than wire rope - because of its low stretch and low mass, there is no risk of whipback. My kids are usually wheeling with me and safety is of the utmost importance in my book.