Hemp rope

“ Approximately, the safe load on a new hemp rope in hundredweights with direct lift is three times the weight in pounds per fathom. On a sound old rope fall one-half the square of the circumference is sufficient load. A Bessemer steel wire rope will safely carry in hundredweights three times the square of its circumference in inches, and a crucible steel wire rope four times the square of its circumference. For hemp ropes the minimum diameter of sheave should be circumference of rope + 2, and for wire ropes the diameter of sheave in inches should be equal to circumference of rope in sixteenths. ”

“ Sheep-Shank (fig. 46) .—Formed by making a long bight in a topgallant back-stay, or any rope which it is desirable to shorten, and taking a half-hitch near each bend, as at a, a. Rope-yarn stops at b, b are desirable to keep it in place till the strain is brought on it. Wire rope cannot be so treated, and it is injurious to hemp rope that is large and stiff. ”

“ The rope spinner carries a bundle of hemp about three feet long round his waist, with the fibres all laid even, and having their ends in front of him, and from these he pulls out sufficient for the thickness of the “yarn” he is spinning, and after slightly twisting it with his fingers, attaches it to the hook of a “whirl,” which is set in motion by the wheel, and as the fibres are twisted he walks backward, gradually adding more and more, a little at a time, so as to keep the yarn of the same thickness throughout. ”

“ Flax is still more generally cultivated than hemp; but its chief application is to the manufacture of cloth, as it does not answer well for any cordage larger than a bed-cord. The formation of cloth from hemp is also very common; and, in this case, the yarn for the coarse cloths is spun on the rope-maker's wheel in the manner already described. The cloth is generally used for making bags, sacking-bottoms for beds, and sails for vessels.
16. Rope-making is a manufacture of general utility, as cordage of some kind is used more or less in every family in all civilized communities ”

“ In preparing the hemp for spinning an ordinary thread or rope-yarn, it is only heckled over a large keg or clearer, until the fibres are straightened and separated, so as to run freely in the spinning. In this case, the hemp is not stript of the tow, or cropt, unless it is designed to spin beneath the usual grist, which is about 20 yarns for the strand of a three-inch strap-laid rope. The spinning is still performed by hand, being found not only to be more economical, but also to make a smoother thread, than has yet been effected by machinery. ”

“ Three ropes laid up left-handed form what is known as a cable-laid rope; four-stranded ropes are laid round a heart. Ropes are sometimes laid left-handed, but if the strands are to be laid left-handed the yarns are laid right-handed. If the parts of hemp, etc., be twisted more than is necessary to hold them together, strength is lost. Upon following the course of a yarn in a rope it will be found that, by this alternate laying, it runs nearly straight with the direction of the rope’s length. ”

“ The experiments made at Fort St. George near Madras in July, 1850, with lines and rigging made of abáca and European hemp, with the view of testing their respective availability, gave the following interesting results: a rope of Manila hemp, 12 feet long, 3 1⁄4 inches in circumference, and weighing 28 11⁄16 oz., required a strain of 4460 lbs. to break it: on the other hand a rope of English hemp of similar dimensions, weighing 39 oz., broke with a strain of only 3885 lbs. A second smaller rope of Manila hemp, 1 3⁄4 inches thick, and 9 1⁄2 oz. weight, also 12 feet in length, required 1490 lbs. ”

“ On discussing the subject in its different bearings, it soon became evident to all, that the matter of supreme importance would be the making of the rope. Could this be manufactured of sufficient fineness not to overburden the bearcoot, and yet be strong enough to sustain the weight of a man, the first difficulty would be got over. The rope therefore should be made with the greatest care. Every fibre of it should be of the best quality of hemp—every strand twisted with a perfect uniformity of thickness—every plait manipulated with an exact accuracy.
Ossaroo was the man to make such a cord. ”

“ Of late years the fine hemp bolt-rope has been much discarded in favour of flexible wire rope, neatly covered with canvas and spun-yarn to prevent rust. This is stronger and more durable in itself, but it makes the sail far more refractory to handle, and cannot be stitched on to the canvas as of old by pushing the big needle in between the strands of the rope. It has to be "marled" on, a method of securing it that always looks clumsy and insecure. ”

“ Hair from the manes and tails of horses is also used. Hemp and flax are most common in the United States. The simplest mode of making rope is under long sheds. After the material is spun into yarn, it is doubled or trebled, and twisted. Ropes for the rigging of vessels employ a large number of men. The great variety and amount of cordage used make it an extensive trade. Ropes are now manufactured in some places by steam. A small number of women are employed in rope making. S. & M., Philadelphia, employ about fifty female hands. ”

“ The very finest hemp, that grown in the province of Piedmont, Italy, is, however, very similar to flax, and in many cases the two fibres are mixed in the same material. The hemp fibre has always been valuable for the rope industry, and it was at one time very extensively used in the production of yarns for the manufacture of sail cloth, sheeting, covers, bagging, sacking, &c. Much of the finer quality is still made into cloth, but almost all the coarser quality finds its way into ropes and similar material. ”

“ When fastened in this way he is exceedingly likely to get his fore leg over the rope and get hung up in it, a nasty wound in the heel or at the back of the knee being the result, if nothing worse; whereas, if the ropes are pegged out on each side, he can move about freely, and it would be difficult for him to get his leg over them. Both head and heel ropes should be made of hemp; the cotton rope used in India for most purposes is not strong enough, and soon breaks and wears out. ”

“ Willows and other tough flexible sticks or twigs are readily converted into rope by simply twisting them together; they should, however, be well soaked in water before twisting. An almost endless number of trees, shrubs, and plants yield fibre well calculated for cord or rope-making purposes. The bark of some of the mimosas is as tough as the finest hemp, and can be stripped from the trees in any quantity. ”

“ Wire ropes are used, not only because they last longer, if kept greased, but because a sufficient number of coils will go on a barrel of less than half the length that would be required for hemp ropes of the same strength, without overlapping, which it is as well to avoid, if possible, though it is not so injurious to wire ropes as it is to hemp ones. ”

“ The rope will now look like Fig. 2. Give the two middle strands, G and H, a lick of tar if the rope is of hemp, and grease if of manilla, and knot them together with an overhand knot, taking care that the knot is so formed as to follow the lay of the rope. Then halve these strands and pass them over one strand and under two. Treat the remaining strands in the same way, after which stretch the rope well and cut off the ends of the strands. A long splice is the neatest way there is of putting two ends of a rope together. ”

“ If the hemp should be used for the manufacture of tarred rope—the yarn is now tarred—the reels of yarn are first warped into a haul, that is, the yarns are unwound from the reel and stretched out straight and parallel, and assembled together in a large group, called “a haul,” consisting of between three and four hundred yarns, each a hundred feet long. The haul is dipped into a copper of hot tar, and, being dragged through a grip or gauge, the superfluous tar is squeezed out; by the aid of a capstan the haul is gradually drawn forward until the whole has passed through the tar kettle. ”

“ The harpoon is used almost entirely as a thrusting weapon, but a good man can set one fast by casting if the occasion demands it, up to a distance of 20 ft. The harpoon line, which is ‘grummeted’ round the shank of the head, consists of sixteen fathoms of two-inch tarred rope, very carefully made of the finest hemp, ‘soft laid’ ”

“ It is also termed purchase-rope; but four-stranded rope is frequently used for standing rigging. All the strands are finer, of better hemp, and pass the gauge. Thus the patent shroud-laid rope, made from clean Petersburgh hemp, was found to break at a strain between 63⁄4 and 71⁄4 cwt. per inch of girth in inches squared. Thus a patent rope of 5 inches would require 175 cwt. Common rope, 25 threads in each strand, broke with 5 cwt. per inch, and fell off at 130 threads to 4 cwt. per inch. Thus,
SHROUDS. The lower and upper standing-rigging. They are always divided into pairs or couples ”

“ Nor will the term "long fiber" insure the purchaser obtaining the proper material in his rope, for the longest manila fiber, contrary to general belief, is not always the best from which to make a transmission rope. Some of the extremely long variety is coarse and brittle. The best fiber for transmission rope is a particular grade of manila hemp known as Zebu, Fig. ”

“ It is made by first tying a slip knot so that it will run on the short end of the rope. Then complete by tying a half hitch with the short end as shown.
Fig. 67. The Fisherman’s-bend is similar to the Fisherman’s-hitch except that the half hitches are replaced with whipping.
Fig. 68. A Taut-line-hitch is used for attaching a rope to another rope already under strain, where no slack is available for making any other hitch. It is not secure unless pulled very tight. A few threads of hemp or marlin served about the taut line for the knot to pull against will improve the hitch. [34]
Fig. ”

“ When all the ends are wrapped and cut to such a length that they just butt against each other when worked inside the rope, the work is ready for tucking. Take hold of the piece of hempen core A (Fig. 186) and pull it out just to past the first joint—that is, the two ends 1 and 1′. In all probability, if the rope is large or rather hard laid, this will be difficult, unless a tapered round spike is driven through the two strands immediately behind it. ”

“ So highly perfected is the apparatus that by machine work entirely66 the separate hanks of fiber are combed and elongated into a soft, continuous sliver of any size desired and of convenient length, glossy in appearance, perfectly clean, and with each fiber lying as nearly as possible in the straight position which gives it maximum strength. These operations, in which the entire character of the comparatively short vegetable fiber changes seemingly, are wholly a development of modern rope-making, since in the days of hand spinning no sliver was necessary. ”

“ Large ropes are very liable when new to give considerable trouble by their disposition to kink. It is therefore often necessary to take the extra twist out of them by fastening one end high up in a conveniently grown tree, and suspending a spare waggon wheel from the other, as shown in the illustration (p. 791) . The use of tar in the manufacture of rope tends to impair its strength, but adds to its power to resist deteriorating influences. ”

“ Binder twine is always given what is known as a right-hand twist, but rope yarns must, for certain kinds of rope, be given a left-hand twist. This is accomplished75 by reversing the direction of the capstans. The flyer carries four grooved wheels—two for the right, the others for the left-hand yarn—and by these the yarn is guided from the capstans to the revolving bobbin.
The spinning room, with its hundreds of flyers, each running in the neighborhood of 1,500 revolutions a minute, speaks eloquently of the years’ changes. ”

“ Some ropes stretch more than others in working, and it is difficult to say accurately how much per cent. a rope will stretch, as much depends on the way the rope has been made. However, the larger [Pg 144] the hempen core inside the rope or the shorter the lay or spiral twist the more the stretch. It is wise, therefore, when splicing a new rope never to give any slack away.
Having got the rope hauled as tight as possible, carefully measure 30 ft. from each end of the rope, and there tie a strong whipping. ”

“ In this way, the ropes counteract one another in the twist, hanging like a ribbon down the shaft; and are stitched strongly together by a small cord. Such rope bands are not only very pliable for their strength, which protects the heart of the rope from breaking, but as they lap upon themselves, a simple sheave serves as a rope-barrel. They possess the additional advantage, that by so lapping, they enlarge the diameter of the axle in which they coil, and thus make a compensation mechanically against the increasing length of rope descending with its corve. ”

“ The outside hand, by lowering or lifting the slack lengths below or above the level of the raised thigh, diminishes or increases the friction of the rope round the thigh, and so controls the pace. If a complete rest is needed, the outside hand merely brings up its double rope to join that held by the inside hand, and a very light clasp of the two hands together on the four ropes so united, aided by the almost total arrest of the rope passing under the thigh, easily stops the descent. It is a mistake, but a frequent one, to start the rope round the inside thigh. ”