TOWING SYSTEM DEVELOPMENT

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SALVAGE TOWING.

TB-55-1900-232-10 U.S. Army Towing Manual

TABLE 1-1. U.S. Navy Open-Ocean Salvage Towing Ships.

TB 55-1900-232-10

and are further discussed in Section 4-10 The commercial equivalent is the optional towing capability

stimulated by the International Maritime Organization (IMO) and other organizations as described in Appendix

1-3 TOWING SYSTEM DEVELOPMENT

Towing systems include various components of which the towing vessel or tug is most prominent However, the

tug must have other items to make up the connection to the towed vessel. This section will look first at towing

vessel developments and then at the towline connection system of hawsers, connecting elements, winches and

towing machines.

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TOWING VESSELS-OCEAN TUGS AND RESCUE SALVAGE SHIPS.

These tugs and

salvage/rescue types of ships are the only U.S Navy oceangoing ships whose primary mission is towing. Thus,

they are the only types that are considered to be purpose-built for towing and for which towing activities have

significantly influenced the design.

Most of the Navy purpose-built towing ships in use today are carryovers and replacements or successors to

similar ships used or developed during WWII. Table 2-1 begins with a listing of these WWII ship classes and

continues through their successors that are currently in use in the Navy Some of the differences between the

WWII-vintage and the more modern ships lie in increased horsepower and bollard or towline pull, hawser size,

provisions for use of synthetic fiber hawsers, and, of major importance, vastly improved onboard equipment

and accommodations. The latter classes are summarized below-

a. ATF 76 Class-The ATF Class consists of large ocean tugs of the UTE Class and were excellent all-

purpose ships. Their long-range, high horse- power and excellent seakeeping characteristics made

them particularly suitable for operations in combat zones They also are excellent for towing large

vessels, including dry-docks. They have off-ship firefighting and salvage facilities, and are equipped

for ship rescue, emergency damage control, and ship repair. A limited number of this ship class

remain in service.

b. ASR 7 Class-These ships were originally designed and equipped primarily for rescuing crews from

sunken, disabled submarines They are now equipped for towing special arrays and the NR-1

research submarine. Those currently in Navy service can support surface-supplied he- hum/oxygen

diving to a depth of 300 feet and can quickly moor in water depths up to 1,000 feet. They are

currently equipped with AAJ 250/260 towing machines.

ARS 6 and ARS 38 Class-These ships of the ESCAPE and BOLSTER Classes are steel vessels

designed for Navy offshore salvage work in overseas areas. They carry a large amount of salvage

gear and supplies, and are intended to be stationed just outside the immediate combat zone until

required for rescue or salvage. They have, until recently, been the backbone of the Navy salvage

forces They are excellent long- distance towing vessels and are equipped with AAJ 250 towing

machines

d. ATA Class-This class of tugs was designed for major towing operations at sea, and they had

relatively long endurance. Their intended mission was major towing operations outside combat

areas and Fleet support operations in peace- time They could, therefore, stand by just outside a

combat or operational area and be in position to take the tow from an ATF that might be towing a

disabled vessel to a repair base or safe haven. Although not intended for it, the ATAs per- formed

some firefighting and salvage duties

e. ATS 1 Class-The three ships of this class are excellent towing and salvage ships. These English-

built ships have two 3,000 foot, 2l/4-inch main towing hawsers in- stalled on a Stothert and Pitt

automatic towing machine which was built under license by Almon A Johnson, Inc. The

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