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 TB 55-1900-232-10
FIGURE 2-10. Types of Chocks.
used to connect the various portions of the towline system to each other and to the tow.
2-4.4 BRIDLES, CHAFING CHAIN AND PENDANTS. The towline component located at the tow's deck edge usually is a
chain, because of its superior resistance to chafing. It may be in the form of either a single element or a two-legged
bridle. See Figure 2-11. Sometimes a heavy wire is used for short tows or emergency situations, but special care is
required to minimize chafing of the wire and damage to the structure from the wire's extremely hard material. If the hard
point is a considerable distance from the fairlead, a fairly short length of chain, sufficient to ride in the fairlead, may be
used to save weight and sometimes to simplify the final connection to the tow, such as when using bitts as the hard point.
2-4.5 LEAD CHAIN AND WIRE PENDANT. A lead chain or wire pendant usually is inserted out-board of the chafing
chain or chafing pendant. In the case of a lead chain, it may be the same size as, or simply an extension of, the chafing
chain. A chain extending forward from the apex of a towing bridle also is a lead chain. The purpose of the lead chain is
to add weight to the end of the towline system. This improves the spring in the system by increasing the towline's
catenary. Sometimes the chafing/lead chain is the tow's anchor chain, which can be veered to the desired total length.
A wire pendant often is used in addition to, or in lieu of, the lead chain. It sometimes is called a "towing pendant." Its
purpose is to facilitate the final connection between the towing ship's hawser and the chafing, or lead chain. The pendant
may be up to 300 feet long to permit connection/disconnection on board the tug, while maintaining a safe standoff under
heavy weather conditions.
2-4.6 SYNTHETIC SPRING. A synthetic spring sometimes is inserted between the towing pendant and the towing ship's
hawser for dynamic load mitigation. Most frequently seen in commercial towing, the spring usually is
2-17
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