In the early 1950s, available ropes were generally cotton, sisal or manilla. Cotton rope was rightly relegated to clothesline and similar lubberly duties. Sisal was good for tieing lumber on top of a car, but not much else. Manilla rope was the only practical choice for boats.
Manilla was reasonably strong, not too expensive and easily spliced. (Three-strand manilla rope is still the best to use when you're learning splicing.) Yet, with all these good qualities, manilla rope virtually disappeared from the boating scene. Why?
The answer is that manilla is a natural fiber of the abaca plant. Unless you're a calloused shellback, hauling on a manilla line is almost sure to imbed invisible splinters in your hands. These splinters are too small to pull out with tweezers, so the only practical way of removing them is to let them fester out (ouch!).
Splinters are only an irritation, not the real problem with manilla rope. Being a natural fiber, manilla is subject to rot, especially when wet. Putting a damp manilla anchor line into a locker could reduce it to uselessness in just a few days. Even when properly cared for, manilla line had a limited lifespan. Sooner or later, it would start to deteriorate.
Thank goodness those days are gone. Modern nylon, dacron or polypropylene ropes simply don't rot. You can put them away wet without fear of returning to a locker of twisted dust. But, as good as modern rope materials are, they can still be damaged by misuse. It pays to know how to choose the right rope and how to protect it from damage in service.
Ropes can be constructed in a variety of ways, but the two of interest to boat owners are conventional three-strand and braid. People have been making multi-strand twisted rope virtually since the beginning of recorded history. Braided ropes are the result of the Industrial Revolution. They didn't come into general use until machines were designed to take over the drudgery of making rope.
Twisted rope can be made of two, three or more strands with three strands most common. Each strand is, in turn, made up of a bundle of yarns (seven is the usual number) and each yarn is made up of fibers. This type of rope is held together by the tensions created by the opposite twists in the yarns and strands.
In hawser-laid rope ("normal" or "right-hand" twists), the fibers are twisted clockwise to make the yarns. The yarns are then twisted counter-clockwise to make the strands. Finally, the strands are twisted clockwise to complete the finished rope. Twisted rope stays twisted because any attempt to untwist the strands tightens the twist of the yarns.
Braided rope is another story. In this type of construction the fibers are spun into yarn, but the yarn is not twisted into strands. Instead, the yarns are woven into an eight-strand square sennit. The resulting construction is hollow. It resembles those so-called "Chinese finger handcuffs" you probably played with as a child.
Virtually all braided line of 1/4 inch diameter or larger sold in this country is called either "double braid" or "braid-on-braid." There is no difference between these terms. Both refer to a construction in which the outer sennit is woven around an inner core sennit of slightly smaller diameter. The result might be described as a "rope within a rope."
Small diameter braided lines for flag halyards and other light duty applications are often single braid construction. For technical reasons, solid braid construction is roughly half as strong as hollow sennit, limiting this type of rope to non-critical jobs.
In most applications, twisted and braided ropes can be interchanged without harm. However, each type of construction has its advantages and disadvantages:
* Lower initial cost.
* Easy to splice.
* More elastic (stretches more).
* Subject to hockles.
* Generates torque under load.
* Stronger than equal size braided rope.
* Less elastic.
* More difficult to splice.
* Holds most knots better (except Matthew Walker).
* Works better on winches due to more contact with drum.
* Tangles easier.
Most people prefer to use braided rope for mooring lines primarily because it has a better feel in the hand. Virtually all sailboat-running rigging is made of braided rope. Twisted rope is generally preferred for anchor rodes because of its slightly greater elasticity. I find that it's a bit easier to get a good grip on wet three-strand than wet braided rope, another reason for favoring it as an anchor rode.
Man-made fibers have completely supplanted manila. Today, you have the choice between nylon, dacron or polypropylene. With a bullet-proof wallet, you might also consider exotic materials such as kevlar. Each of these fibers is suited for specific applications. The trick is choosing the right fiber for the job.
Even though there is no such thing as an "all purpose" rope, nylon comes pretty close. It is the material of choice for mooring lines and anchor rodes where shock loads are likely to be encountered because it absorbs shocks by stretching up to 25 percent before reaching its elastic limit. Nylon has a relatively high resistance to deterioration from ultra violet light chemical exposure.
While stretch may be good under some circumstances, it is also a disadvantage of nylon. You would not want to use this fiber for sailboat halyards or sheets which require critical adjustment. Nylon stretches too much for a trailer winch line. Most people are unaware that nylon loses up to 15 percent of its tensile strength when wet. It has only moderate resistance to chafe, so must be protected where it passes across sharp edges.
Dacron or polyester rope is similar in feel and appearance to nylon, but has several important difference. For one thing, it doesn't stretch. This makes dacron rope ideal for sailboat halyards, but not as well suited for an anchor rode. Getting wet does not alter the strength of a Dacron rope and it is less subject to damage from chafe.
Polypropylene makes a great ski tow rope because it has the unique property of floating. You don't have to worry about getting it tangled in the propeller. However, this is about the only advantage to this type of rope. The disadvantages of polypropylene include low resistance to chafe and low tensile strength. Keeping a knot tied in poly line is one of life's frustrating tasks.
Breaking Vs. Working Strength
Rope strength is described in two ways. Breaking strength refers to the maximum load the rope can handle before it fails catastrophically. The number of pounds required to break a modern nylon rope can be astounding: about 11 tons for a one-inch line! But, breaking strength is not the critical factor in choosing rope.
Of far more importance is the rope's working strength. This is a measure of the maximum safe load and is always a fraction of the breaking strength. By dividing the breaking strength by the working strength, you calculate what is known as the "safety factor." Safety factors go up as the size of the rope decreases.
You should always choose a rope with a working strength that exceeds the maximum load it will be expected to carry in normal service. In this way you take full advantage of the safety factor. Should the rope come under some unexpected stress, you have plenty of strength left.
It's important to note here that you do not always want to purchase the strongest possible rope. For instance, in some situations you may want the rope to part before the strain damages some more expensive item. This is often the case with spinnaker sheets on sailboats. Or, an oversize anchor rode will transmit too much shock load to the boat because it won't stretch properly.
Another important factor in choosing rope is its elastic limit. This measures how far the rope can be stretched under load before permanent damage is done. Any rope stretched beyond its elastic limit must be considered as suspect and should be discarded. When new, most yacht ropes can be loaded to 60 percent of their breaking strengths before reaching their elastic limits.
Rope available on today's market varies from excellent quality to virtually unusable. Unfortunately, it's pretty much "buyer beware" as lengths of cut rope usually cannot be returned. This means you shouldn't be opposed to spending a few extra minutes or a few more dollars picking the best product available.
From my experience, the biggest variables come in the quality of twisted nylon line. Some of the generic twisted nylon rope being sold today is terrible! When in doubt, avoid unbranded rope. Inferior products often have less than half the lifespan of name brand ropes, so are more costly in the long run.
Twisted nylon rope should be soft enough to tie into knots, yet hard enough not to hockle. Carefully examine the individual yarns that make up the strands. Tufts of yarn pulled out of the strands indicate a rope too soft for hard duty. Splicing a twisted rope that is too soft will teach you a whole new vocabulary of blue words.
In inspecting line for purchase, look for places where the individual yarns are spliced together. Only the most expensive product is made from yarns longer than the finished coil of rope. Ropes you and I buy are usually made from yarns which are shorter than the finished coil. This means splices are necessary, but they should be minimal and located at considerable distance from one another.
All synthetic rope should contain ultra violet inhibitors which reduce damage from exposure to sunlight. Darker ropes are generally less susceptible to sunlight than ropes of lighter color.
Use And Care Of Rope
When not in use, rope should be stored in a well-ventilated locker. Modern synthetics do not rot, but they are susceptible to mildew. I've always suspected that some whole-boat infestations of mildew started with a coil of damp rope improperly stowed. I know for a fact that wet synthetic line can develop a powerful gamey odor.
Chafe is Enemy Number 1 of rope. Any time a working line crosses a sharp edge (cleat, chock, pier edge, etc.), chafe will result. It can chew through polypropylene line in a matter of minutes. Nylon may resist for days or weeks and Dacron for months, but all rope will eventually succumb to chafe.
Temporary chafe protection can be obtained by wrapping old rags around a working line. More permanent protection can take the form of permanent leather wrappings sewn to the rope or split lengths of garden hose.
Dirt ground into the fibers of the rope can act like miniature cutting tools. This is one reason why anchor rodes often fail at the end nearest the ground tackle. Carefully rinsing off the rode can extend its lifespan. Even so, it pays to exchange the working and bitter ends after a few years of service. This retires the potentially damaged portion of the rode to less strenuous duty while putting fresh rope out where the work's being done.
Dirt ground into a line can be removed by running it through a wash cycle in an ordinary washing machine (when mama isn't looking). Coil the line in a mesh bag to prevent it from becoming tangled either in itself or in parts of the washer. Use a mild detergent and plenty of rinse water. Do not spin dry as you are sure to have an unbalanced load in the machine.
Keep in mind that modern synthetic ropes do not show deterioration the way that old-fashioned manila did. A nylon line may still look good, but have lost a considerable portion of its strength to ordinary wear. Questionable lengths of rope should never be used as mooring or anchor lines. Use them instead for lashings or other non-critical applications.
Coiling rope is a seaman's art. Nothing marks you as a lubber more than wrapping a line into a tight bundle around your arm. It only takes a few seconds to learn how to coil rope correctly. You may be surprised to learn that this is one case where doing the job right is also doing it the easy way.
Pick up the line in your left hand. Let it lie in the palm of your left hand with your thumb pointing away from your body. Gather in loops of rope with your right hand. As each loop is laid into your left hand, impart a slight twist with your right thumb and forefinger. Twist the rope away from your body. The result will be neat coils that lie quietly in your left hand.
This method of coiling works best with twisted rope. Braided ropes coil nicely this way, but when you uncoil them that half twist you imparted to make the coils turns braided rope into a self-tangling mess. The solution is to use what I call the "un- coil."
The uncoil is a method of laying loops into your left hand so that each loop has the alternate twist to the previous one. These twists cancel each other out when the rope is uncoiled, thereby preventing much grief. The trick is to reverse the position of your right hand on alternate coils. Do the first overhand in the normal manner. The second coil is made underhand; the third overhand...etc. until the rope is coiled.
Finally, learning to splice is not difficult. Most people can get the knack of putting an eye splice in twisted rope with only minimal practice. Splicing braided rope takes more concentration. (I still have to read the instructions every time). By splicing your own set of dock lines you'll not only get the satisfaction of doing the job yourself, you'll also save money. Do-it-yourself lines cost up to one-third less than those that are factory spliced.
The Bitter End
Whether manila or dacron, twisted three strand or braid, the cut ends of lengths of all rope will unravel if not properly protected. The ends of modern synthetic rope can be "sealed" with a hot knife. All you do is melt the individual strands into one congealed mass. Done well, the melted end should be the same diameter as the rope and present no sharp edges or burned spots. (Be careful when melting synthetic rope. Molten nylon or dacron can produce a nasty burn. Always work so that any drips will fall harmlessly away from your exposed skin.)
Melted ends are easy, but they prevent unraveling only at the tip of the rope. Often, the rope behind a melted end of three- strand will begin to untwist. Or, the inner sennit of braid will begin to pull away from the outer. The only ways to prevent these occurrances are to apply either a proper whipping or back splice to each end. Whipping is generally preferred with twisted rope, backsplices with braid.
A whipping is simply a wrapping of a wax-impregnated twine that is known as "marline" around the rope. Depending upon the need, whippings can be temporary or permanent. A sailmaker's palm and needles are necessary to make a permanent whipping which is actually sewn to the rope.
Whippings are both nautical and long-lasting. My last two sets of dock lines became "long jawed" from use well before the sewn whippings started to loosen.
Start a permanent whipping by pushing a needle threaded with waxed marline through the rope a couple of inches from the end. Leave a portion of the bitter end of the marline exposed. Nip this bitter end with the first few turns of the whipping. Wrap the marline around the rope against the lay. Remember the sailor's ditty: "Worm and parcel with the lay, turn and serve the other way." Pull each turn as tight as you can without distorting the rope.
The completed whipping should be as long as the diameter of the rope. Thus, a 1/2-inch rope requires a 1/2-inch long whipping. Once the required number of turns have been applied, the marline is sewn back through the rope. Then, stitches are taken to pull the turns of the whipping into the lay of the rope. Once the stitching is complete, you cut off the bitter end of the rope about 1/4 inch from the whipping.
For a complete description of whipping, I suggest The Marlinspike Sailor by Hervey Garrett Smith or The Ditty Bag Book by Frank Rosenow or Modern Marlinspike Seamanship by William P. MacLean.
Braided ropes seem to last longer with back splices. Anyone who has ever wrestled with a crown knot trying to backsplice traditional laid rope is probably questioning this statement. But, with braid, a back splice is just an eye splice with no eye. Very simple, if you follow the directions. The result is neat and lasts as long as the rope.
Never use masking or electrician's tape to seal the end of a rope. Boats operate in a wet environment and water loves to turn tape into goo. If you don't have time to do a proper job, simply tie a stopper knot in the end of the rope and wait for a rainy day. A figure-eight knot works well in this temporary duty.
Typical Breaking & Working Strengths Twisted & Braided Ropes
Note: Breaking and working strengths in pounds for typical new rope. Consult manufacturer for specific information on particular brands of rope.