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The Anatomy of Rope and Cordage
Upon acquiring his first boat the embryo yachtsman discovers that its use is going to involve intimate, personal contact with rope and cordage, and to a far greater extent than he anticipated. He learns that rope has an infinite number of applications in which he will be called upon to employ diverse knots, bends, hitches and splices. It must be secured to a variety of objects, temporarily or permanently, withstand all manner of stresses and strains and withal perform efficiently and safely at all times. In short, rope has suddenly assumed an importance that he cannot ignore, and, if he is an average landsman, is not prepared to cope with.
To put rope to work intelligently, and to make the most of its amazing versatility calls for something more than the ability to tie a simple knot or hitch. When you consider that the same rope which might some day save your life can just as efficiently kill or maim, it should be evident that a thorough understanding of its structural characteristics is vitally important.
Suppose we unlay a section of half-inch, common Manila rope to examine its component parts and the nature of its construction. You will observe that the three strands are right-laid, that is they spiral around the rope to the right, or clockwise. Each strand is composed of seven individual yarns or threads which are left-laid, or twisted counter-clockwise. Right there is the reason rope constantly holds its form and resists any tendency to unlay. If you grasp a rope with your two hands a couple of inches apart and try to unlay it or separate the strands you will notice that a quarter of a turn is about all you can comfortably gain. In trying to untwist the rope you were actually attempting to lay up the yarns more tightly.
Each yarn is composed of a group of natural fibers twisted together right-handed, and careful examination will disclose that despite the spiral construction of rope, every fiber of it runs constantly straight in the direction that the rope lies. That is the secret of its strength, and an important factor limiting the amount of stretch.
Such is the simple manner in which rope is put together—fibers spun or twisted right-handed into yarns, yarns laid up left-handed into strands, and the strands right-laid to form the finished rope. But elementary though it may seem, it is imperative that it be firmly fixed in your mind if you would master the arts of the sailor, for the natural lay of the parts must be preserved at all times. Any loosening or tightening of the normal "twist" of the strands or yarns greatly reduces the strength of the rope and shortens its life. In splicing and numerous other operations where it is necessary to unlay the rope and disarrange the strands, you must be able to restore it to its original lay, so that every yarn bears an equal share of the load. All too many otherwise-proficient yachtsmen ignore or forget this simple fundamental when they turn in a splice, and as a result you find one strand overstrained and the other two inert.
The fibers of Manila rope are inherently wiry and stiff; thus it has a natural tendency to hold its lay and is relatively easy to work with. At the other extreme is cotton rope, in which the fibers are soft and limp. When you cut cotton rope it instantly unlays for a considerable distance and falls apart at the touch. Once unlaid, it resists every attempt to restore its original form and therefore is somewhat difficult to splice.
Rope gains in strength when it becomes wet because the water softens the fibers and "fairs up" the lay. Likewise knots, bends, and hitches tighten up and are much stronger when wet. In fact, many knots and hitches are unsuited for use at sea because they get so tight when wet that it is almost impossible to untie them, and there are times when this fault could have tragic consequences.
Wet rope also shrinks. When a dry rope, stretched taut and secured at each end, becomes wet terrific strains are set up and something has to give. One of two things inevitably happens—either the part to which it is attached tears loose or the rope is stretched beyond its recovery limit and is permanently damaged. Rope that has become so attenuated and has lost much of its twist is called "long-jawed." Never leave a dry rope set up taut, be it sheet, halyard or dock line, for the first shower to wet it can destroy much of its usefulness.
The two greatest enemies of rope are friction and rot—both of which can be combatted by proper care and handling. Internal friction, the constant rubbing together of the fibers, can result from the use of blocks with sheaves of too small a diameter, or conversely, too large a rope for the block. External friction, which chafes and cuts the surface fibers, can be caused by many things. Dragging rope along the ground or over sharp surfaces, failure to apply chafing gear, improper "lead" of running rigging and use of cleats too small for the size of rope used—all help in the rapid depreciation of rope. Kinks and snarls are also enemies, and the prudent sailor constantly overhauls his rope by coiling it down neatly so it is ever ready to run free. Never put a strain on a rope that is kinked or whose normal lay has been distorted.
Rot is caused by a fungus which thrives on dampness. Immersion in sea-water leaves the rope impregnated with salt, which continually absorbs moisture from the air and makes it difficult to entirely prevent rot from starting. However, you can delay its progress by keeping your rope as dry as possible, well aired and out of the sun. Never put rope below deck when wet, and store only where it is well ventilated. An occasional bath in fresh water will remove salt, keep rope soft and pleasant to handle, and prolong its life.
There are a number of excellent rope preservatives available which have gained considerable popularity, particularly among commercial fishermen, who use them for the prevention of rot in nets and rope. Rope so treated is inclined to be somewhat sticky and therefore not too desirable for sheets and halyards; but for preserving mooring and anchor cables which are continuously wet I can heartily recommend the treatment. Six years after applying one of these preservatives my cables show no sign of rot or "powdering," and the initial stickiness has long since disappeared.
In spite of every care taken to prolong its life, there comes a time when rope should be replaced. Normal wear, exposure to the elements, and old age take their toll and it can no longer be trusted. To determine just when that point has been reached you must recognize the signs when they appear, and that means careful, periodic inspection. The best indication is the condition of the fibers. Those on the surface are broken, and the rope has a hairy look. Unlay a strand and pull out a fiber. Notice that it is only a few inches long, whereas it was probably ten or twelve feet long when the rope was new. The inside fibers will be matted and powdery, have a lifeless, gray look and some will be broken. The rope will have completely lost its original wiry springiness, and no elasticity remains whatsoever. Notice how much smaller its diameter is compared to what it was when new—three-eighths rope has probably become five-sixteenths—and it is decidedly long-jawed. It should be obvious that the time to replace rope is before this point has been reached rather than after it has parted in use.
In the foregoing discussion the term "rope" has been used in its broader, more generic sense. But there are many kinds of rope, each with its own characteristics, and none universally suitable for every use. There are also the "small stuff," light lines and seizing material under the general heading of cordage, each with specified uses and having its own peculiarities. To choose the right one for the job in hand, and to use it intelligently, you must have a basic understanding of the various materials at your command. To that end I suggest we have a look at them, see where they may be used, and learn why they act the way they do.
The fibers used in the manufacture of Manila rope come from a plant called "abaca" grown in the Philippines. These fibers run anywhere from three to ten or twelve feet in length, the longest going into only the finest quality of rope. They are graded not only for length, but also for uniformity in size. In their raw state Manila fibers contain a natural oil, and more oil is added when the rope is manufactured. These oils leach away gradually through exposure to the elements, and deprived of their necessary lubrication, the fibers deteriorate rapidly.
There is more Manila rope used in the world today than any other kind, and the chances are that you will be depending upon it most of the time you are afloat. Certain it is that Manila is the most versatile of all, and by and large the most dependable of all rope materials, but you must use careful judgment in its selection. There are many grades of Manila, and no two manufacturers seem to grade their rope in the same manner.
Low grade, poor quality rope is easy to recognize, and has no place on a well-found yacht. It is extremely hairy and coarse, the ends of its short fibers sticking out everywhere throughout its length. Unlay a strand and you will notice that the fibers vary greatly in size, and many are looped, kinked and snarled. Some of the yarns are larger than others, bunchy and gouty, and the lay of the rope lacks uniformity. Such rope is dangerous and unreliable. Its strength is unpredictable and its elasticity is an unknown factor.
The best quality of Manila obtainable is the grade known as "Yacht Rope," and only the very finest of fibers and workmanship go into its construction. Its most noticeable characteristics are the perfect uniformity of its lay, and the absence of protruding fiber ends. It is slick and smooth to handle, reeves through blocks with a minimum of friction, and is extremely long-lived. When unlaid, you will find that every yarn is almost identical, the long fibers are uniform in size and very few ends are visible. The strands are mechanically perfect throughout the rope and have a decidedly sculptured appearance.
Because of the high quality of the fiber and the precision with which it is laid, inner friction is reduced to a minimum and its strength is a constant factor, from one end of the coil to the other. Truly it is a superior product, and hence it commands a considerably higher price than the common grades.
Only slightly below "Yacht Rope" in quality is the grade known as "Bolt Rope." With the same long-fiber construction, it has a slightly harder lay, and like "Yacht Rope," is available in both 3 and 4 strands. After many years of experience in its use I am convinced that 4-strand "Bolt Rope" is unequaled for sheets. Here the rope is constantly moving through the blocks, alternately trimmed under strain and slacked off at high speed. Sheets must run freely without kinking, withstand severe inner friction, and be easy on the hands. 4-strand "Bolt Rope" does all of these with ease, and what is more, resists wear and chafe to a marked degree.
One word of caution ... 4-strand rope is often made with an inner "heart" yarn, or core, and is abominable stuff for yacht use. In a very short time after breaking in, the heart or core breaks in numerous places and works out between the strands to the surface, whereupon it fouls in the blocks and snags on everything. So when buying 4-strand rope be sure it has no core.
Sisal fibers are obtained from the leaves of a plant resembling the cactus and is grown principally in Java. Unlike Manila it contains little or no natural oil and therefore has no resistance to moisture. It has but two-thirds the strength of Manila and deteriorates rapidly. Its short, coarse fibers make a rope that is hairy and rough on the hands. Without the protection of natural oils it soaks up water like a sponge and becomes soft and slippery, and in this state it wears out very quickly. Even the best grade of Sisal is inferior to the common grades of Manila, and the yachtsman looks upon it for what it is—a substitute of last resort.
The fibers of the Hemp plant formerly occupied the high place in rope making that Manila does today. Before the introduction of wire rope Hemp was universally used for ships' standing rigging, and because it stretches very little it was admirably suited for the purpose. For the same reason sails are roped with Hemp, and the amount of stretch can be gauged and allowed for with remarkable accuracy.
Hemp fibers are short, soft and very fine, with none of the springiness so characteristic of Manila, and this necessitates a different construction. For example, in 3/8 inch Manila each strand has 4 threads or yarns, while in Hemp rope of the same size each strand is composed of 6 threads laid up about a core or center thread, making 7 in all. It has a harder lay than Manila yet is more ductile. Untreated Hemp rope soaks up water readily and it then becomes so stiff and rigid that it is almost impossible to handle. Therefore it is customarily tarred (impregnated with pine oil), which protects it from water, weather and rot. It has an extremely long life, which makes it very valuable for standing rigging such as lanyards, ratlines and small stuff for seizings, and I shall have more to say about its general usefulness later.
Although its use is restricted to what we might call lighter duties, Cotton rope is strictly a yachtsman's rope. Clean, white, pleasing to the eye and smooth to the touch, it has great decorative value and adds much to a yacht's appearance. It is entirely unsuitable for sheets, halyards or heavy work because of its limited strength, poor resistance to chafe, and tendency to become hard, stiff and unmanageable when wet. For light work such as manropes, lashings, pennants and signal lines, or anything of a purely decorative nature it truly belongs to a yacht. Because of the soft nature of its fibers it unlays and falls apart when cut, and can be spliced only with difficulty. Containing no natural or added oils it rots easily and has a relatively short life.
Rope made of linen flax is a high quality product of limited usefulness. For running rigging on sailing craft it has no equal, possessing all of the qualities most desired. It is very soft, limp and flexible, with none of the springy resilience generally expected of rope, and yet it is the strongest natural-fiber rope made. Domestic makes are best, some of the imported ropes having an inclination to stiffen when wet and become long-jawed after breaking in. Log lines and lead lines are generally made of braided linen because of its resistance to shrinking and stretching.
Unfortunately the high cost of Linen rope prevents it from achieving the popularity it rightly deserves, and so it falls into the category of luxury items.
Modern science's contribution to rope making, the first practical artificial fiber, has been welcomed by yachtsmen the world over with varying degrees of enthusiasm. In some respects it is superior to all others, but it has certain characteristics restricting its usefulness which should be understood before putting it to work.
Nylon rope is the strongest and most elastic of all. It is impervious to water and rot, can be stowed when wet without deteriorating, seems to last indefinitely and retains its full strength even after hard service. On the other hand it is slick, smooth and slippery to grasp and hold, particularly in the small sizes. It is very difficult to splice, although immersion in boiling water makes the task a little easier. Hold a match flame under it and it will instantly melt, but whether this indicates that long exposure to a hot sun is destructive, I am not prepared to say.
Excerpted from The Arts of the Sailor by HERVEY GARRETT SMITH. Copyright © 2014 Dover Publications, Inc.. Excerpted by permission of Dover Publications, Inc..
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Posted August 12, 2006
This book is a MUST if you own a boat, and is excellent reading if you don't. It's very well written and clearly illustrated. I bought this two years ago and I still use it for all my knotting and splicing questions. Also, it contains lots of other very useful information, and even some stories from the author's own life! Great, fantastic book. Since reading this book, I have picked up two more of his books, and plan to get more. An absolute MUST for all boaters or enthusiasts.Was this review helpful? Yes NoThank you for your feedback. Report this reviewThank you, this review has been flagged.