the loop at the end of the line, as shown in the figure. Wind the standing part around the line covering the loop of the whipping. Leave a small loop uncovered, as shown. Pass the remainder of the standing end up through the small loop and pull the dead end of the twine, thus pulling the small loop and the standing end back towards the end of the line underneath the whipping. Pull the dead end of the twine until the loop with the standing end reaches a point midway underneath the whipping. Trim both ends of the twine close up against the loops of the whipping. Before cutting a line, place two whippings on the line 1 or 2 inches apart and make the cut between the whippings. This will prevent the ends from unraveling after they are cut.
Before stowing a fiber line, you must take certain precautions to safeguard the line against deterioration. You should never stow a wet line. Always dry the line well before placing it in stowage.
After a line has been used, you should coil it down in a clockwise direction (assuming it is a right-hand lay). Should the line be kinked from excessive turns, remove the kinks by the procedure known as "thorough footing." You do this by coiling the line down counterclockwise and then pulling the bottom end of the coil up and out the middle of the coil. If the line is free of kinks as it leaves the coil, make it up in the correct manner. If it is still kinked, repeat the process before making up the line for stowage.
Choose your stowage space for line carefully. Line deteriorates rapidly if exposed to prolonged dampness. Furthermore, it is important for the stowage area to be dry, unheated, and well ventilated. To permit proper air circulation, you should either place the line in loose coils on a wood grating platform about 6 inches (15 cm) above the floor or hang the line in loose coils on a wooden peg.
You should NEVER expose a line to lime, acids, or other chemicals, or even stow it in a room containing chemicals. Even the vapors may severely damage line. As a final precaution, avoid continually exposing line to sunlight. Excessive sunlight will also damage the line.
Overloading a line poses a serious threat to the safety of personnel, not to mention the heavy losses likely to result through damage to material. To avoid overloading, you must know the strength of the line you are working with. This involves three factors: breaking strength, safe working load, and safety factor.
BREAKING STRENGTH. - Refers to the tension at which the line will part when a load is applied. Line manufacturers have determined breaking strength through tests and have set up tables to provide this information
SAFE WORKING LOAD - Briefly defined, the "safe working load" (SWL) of a line is the load that can be applied without causing any kind of damage to the line. Note that the safe working load is considerably less than the breaking strength. A wide margin of difference between breaking strength and safe working load is necessary to allow for such factors as additional strain imposed on the line by jerky movements in hoisting or bending over sheaves in a pulley block.
SAFETY FACTOR. - safety factor of a line is the ratio between the breaking strength and the safe working load. Usually, a safety factor of 4 is acceptable, but this is not always the case. In other words, the safety factor will vary, depending on such things as the condition of the line and circumstances under which it is to be used. While the safety factor should NEVER be less than 3, it often should be well above 4 (possibly as high as 8 or 10). For best, average, or unfavorable conditions, the safety factor indicated below may often be suitable.
BEST conditions (new line): 4
AVERAGE conditions (line used but in good condition): 6
UNFAVORABLE conditions (frequently used line, such as running rigging): 8
Table 1-1 lists some of the properties of manila and sisal line, including strength. The table shows that the minimum breaking strength is considerably greater than the safe working capacity. The difference is caused by the application of a safety factor. The safe working load (SWL) of line is obtained by dividing the breaking strength (BS) by a factor of safety (FS). A new 1-inch- diameter No. 1 manila line has a breaking strength of 9,000 pounds, as indicated in table l-l. To determine the safe working load of the line, you would divide its breaking strength by a minimum standard safety factorContinue Reading