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 TB 55-1900-232-10
a length of synthetic fiber rope, spliced together, arranged into a grommet. See Figure 5-14 and Paragraph 5-5.2.4.
2-4.7 TOW HAWSER. The tow hawser is the primary tensile element of the towline. The tow hawser normally is a wire
rope, however, in an emergency, a synthetic towline may be used. At both the tow end and tug end, if the towing vessel
does not have a towing machine or winch, the hawser is equipped with an end fitting such as a socket, thimble or spliced
eye. When the tow hawser is part of a tug's equipment, it is stowed on the drum of the towing machine, or in the case of
synthetic line, in a bin below deck. When the tow hawser is part of the towed vessel's equipment, it may be stowed on a
storage drum, reel or brackets, or faked down in a tub, ready for use.
2-4.8 TUG STERN ARRANGEMENT. The stern of a tug is designed to minimize chafing of, and damage to, the tug
structure from the hawser. Caprail radius is generous and free from unintended obstructions to the hawser's sweep from
side to side as the tug maneuvers in restricted waters. While towing under steady-state conditions at sea, most tugs
have a system to restrain the tow hawser sweep, such as vertical stern rollers or Norman pins. In any case, chafing gear
usually is used to reduce wear on both the hawser and the tug's structure. Hawser wear also is minimized by frequent
short adjustments in scope to spread the stress point along a length of the hawser.
2-4.9 ATTACHMENT POINTS ON THE TUG. The towline attachment point on U.S. Navy tugs is the towing machine or
traction winch. For wire hawsers, the winch attachment point also serves for hawser storage. The traction machine pays
out, retrieves and holds the hawser, while storage is provided by a separate bin or storeroom. Some older and/or smaller
tugs do not have towing machinery described above and may secure the hawser to a towing hook, padeye or bitts
All U S. Navy towing ships have H-bitts which serve two purposes. They serve to fairlead the hawser to towing
machinery and can serve as an anchor point for holding the hawser with a stopper when required. Use of the H-bitts for
holding the hawser is not frequent and is usually restricted to de-beaching operations or isolating the towing machinery
from hawser tension
2-4.10 RETRIEVAL PENDANT. As shown in Figure 2-11, the retrieval pendant is a wire rope led from the deck of the
tow to the end of the pendant or flounder plate, to facilitate bringing the tow gear back onto the foredeck of the tow so it
will not drag the seafloor or foul the ship's appendages when the tow is disconnected. The retrieval pendant often is
handled on the deck of the tow by a hand-powered winch; it must be capable of being handled by the riding crew or by a
boarding party put aboard the tow. The wire's strength must be sufficient to lift the flounder plate, bridle and/or pendant,
it is not intended to be exposed to towing loads.
24.11 SECONDARY TOWLINE. A secondary or emergency towline is often rigged, especially if the tow has great value
or is carrying hazardous cargo. See Figure 2-12. The secondary towline is intended for emergency, short-term use. It
may be of lesser strength than the primary towline, and is often made up with synthetic rope. Rigging methods will vary
depending on whether the tow is manned or unmanned. The secondary system usually is faked down on deck, rigged
with a heavy messenger led outboard of the ship's structure, terminated by a lighter floating pendant with a marker buoy
trailing astern of the tow. The entire system is rigged so that the tug merely recovers the trailing messenger and heaves
the outboard end of the secondary towline aboard the tug for connection to the tug's hawser.
In all cases, the secondary towline will be already connected to an appropriate hard point on the tow and provided with
necessary chafing protection.
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