TOWLINE AND TERMINAL GEAR
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46 CFR Part 140, Subpart H (Towing Safety) requires that all components of the towing arrangement be adequate for their intended use, that pre-departure inspections of the towing equipment are performed, and that specific records regarding the towing equipment components are maintained.  Construction characteristics and condition of all towing components must be appropriately matched to the horsepower or bollard pull ratings of the towing vessel and considerations of loads applied to the towing gear during intended service must be performed.  Pre-departure inspections of all towing equipment, proper cargo stowage aboard the tow, and confirmation that the towing vessel’s maneuverability characteristics are appropriately matched to the tow for the intended voyage are also required.  The pre-departure inspections tie directly into the navigation assessment requirements of 46 CFR 140.635 where recordkeeping requirements specify that all tow equipment examinations performed be recorded.  Records containing the characteristics (type, size, service use) of each towline must be maintained and available for review by the Coast Guard or third party auditor.  Log entries linking the inspections to recordkeeping must be entered into the official logbook,Towing Vessel Record or as prescribed by the towing vessel’s TSMS. Certain towing vessels also fall under the towing safety requirements of 33 CFR 163 and 164.

Regulatory Cites:

33 CFR 163 Towing of Barges
33 CFR 164 Navigation Safety Regulations
46 CFR 140.635 Navigation assessment
46 CFR 140.801 Towing gear
46 CFR 140.805 Towing safety
46 CFR 140.820 Recordkeeping for towing gear

Records of towline, towing gear and terminal gear inspections/examinations must be recorded in the Towing Vessel Record (TVR), official logbook or IAW the vessels approved TSMS.  Towing gear used in conjunction with towing astern must meet the recordkeeping requirements of 33 CFR 164.74.    

The recordkeeping requirements for face wires and spring lines used for towing ahead or pushing alongside include only the wires or lines which connect the towing vessel to the tow by means of stationary rigging.  

Items to check:

  • Records of towing gear contain required information:
    • Results of inspections/examinations documented
    • Dates of inspections/examinations
    • Identification of each item inspected/examined
    • Name(s) of the person(s) who conducted the inspection/examination
  • A record of the type, size and service of each towline, face wire, and spring line used to make the tow vessel fast to the tow.   

Regulatory Cites:

33 CFR 164.74 Towline and terminal gear for towing astern
33 CFR 164.76 Towline and terminal gear for towing alongside and pushing ahead
46 CFR 140.820 Recordkeeping for towing gear
46 CFR 140.915 Items to be recorded

The owner, master, or operator of each vessel towing astern must ensure that the gear used to control, protect, and connect each towline meets the following criteria:

  • Material and size of the terminal gear are appropriate for the strength and anticipated loading of the towline and for the environment
  • Each connection is secured by at least one nut with at least one cotter pin or other means of preventing its failure
  • The lead of the towline is appropriate to prevent sharp bends in the towline from fairlead blocks, chocks, or tackle
  • Mechanical or non-mechanical method(s) to easily release the towline do not endanger operating personnel
  • Towline is protected from abrasion or chafing by chafing gear, lagging, or other means.  

Thimble clip

Spelter socket

Astern barge make up

Chafing gear arrangement

 

Items to check:

  • Connections are secured by at least one nut with cotter pin or other means
  • Lead is appropriate to prevent sharp bends
  • Means of quick towline release
  • Towline protected from chafing
  • Fitted with a winch (Not required on a vessel towing in ice on Western Rivers or using a towline of synthetic or natural fiber)
  • If fitted with winch drum, has a drum brake of adequate holding power  

Regulatory Cites:

33 CFR 164.74 Towline and terminal gear for towing astern
46 CFR 140.801 Towing Gear

When selecting a towing system, for pushing ahead, towing along side or towing astern no one size fits all.  The rigging, wire and lines required will vary in size composition, construction and strength depending on the towing methodology, dynamic loading and the environment in which it is used.

Breaking strength is the average force at which a product, in the condition it would leave the factory, has been found by representative testing to break, when a constant increasing force is applied in direct line to the product at a uniform rate of speed on a standard pull testing machine.  It should be understood that breaking strength, when published by the supplier was obtained in a laboratory under conditions which are almost always impossible to duplicate in actual use.  

When choosing wire rope, synthetic and natural fiber lines, and cables, a design or safety factor should be computed by dividing the computed breaking strength by the stated working load, expressed as a ratio.  For example 5 to 1, which is a ratio commonly referred to as the safe working load.  The safe working load is generally thought of as no more than 1/5 of the lines breaking strength.    In other words the wire rope should be 5 times stronger than the expected load.  Always use manufacturers breaking strength when available to calculate the safe work load.  

The owner, operator, and master should ensure that lines and wires are properly installed so as to guard against damage while in use.  They should also identify inspection and retirement criteria and insure that these are communicated to the crew.  Crew training on proper care, handling and repair of towing gear should also be addressed.  

Tests and inspections of towing gear must occur before the vessel embarks on a voyage of more than 24 hours or when each new master or operator assumes command:

  • Visual inspection of tackle
  • Connections of bridle and towing pendant, if applicable

Wire diameter measurement 

Procedures addressing emergency situations related to the tow, i.e. lost barge retrieval, are to be developed, and crews are to be properly trained accordingly.

Barge recovery

Barge recovery low speed approach


Barge recovery higher speed approach

Items to check:

  • Strength of each component adequate for intended service
  • Size, material and condition of towlines, lines, wires, push gear, cables and other rigging appropriate
  • Emergency procedures related to the tow / barge retrieval in place and provided to the crew  

Regulatory Cites:

33 CFR 164.80 Tests, inspections, and voyage planning
46 CFR 140.615 Examinations and tests
46 CFR 140.801 Towing gear

The owner, master, or operator of each vessel towing astern must ensure that the strength of each towline is adequate for its intended service, considering at least the following factors: 

  • The size and material of each towline being appropriate for the vessel horsepower or bollard pull
  • Static and dynamic loads expected during the intended service
  • Sea conditions expected during the intended service
  • Exposure to the marine environment and any chemicals used or carried on board the vessel
  • Temperatures of normal stowage and service on board the vessel
  • Likelihood of mechanical damage
  • Compatibility with associated navigational-safety equipment.   

Each towline must be rigged free of knots; spliced with a thimble, or have a poured socket at its end; and free of wire clips except for temporary repair, for which the towline must have a thimble and either five wire clips or as many wire clips as the manufacturer specifies for the nominal diameter and construction of the towline, whichever is more.  

The condition of each towline must be monitored through records (kept on board the towing vessel or in company files) of the towline's initial minimum breaking strength as determined by the manufacturer, a classification society, or by a tensile test.  Once a towlines record lapses for three months or more, except when a vessel is laid up or out of service or has not deployed its towline, the owner, master, or operator should retest the towline or remove it from service. Towlines purchased from another owner, master, or operator with the intent to use as a towline, or if a towline is retested for any reason, up-to-date records for the towline must be available for each retest of minimum breaking strength as determined by a classification society or a tensile test.  Visual inspections of towlines should be made at least monthly, IAW with manufacturer's recommendations, or whenever the serviceability of the towline is in doubt.

Items to check:

  • Towline as rigged is free of knots & spliced with thimble or poured socket
  • Any temporary repairs made with thimble and minimum of five wire clips   

Regulatory Cites:

33 CFR 157.04 Authorization of classification societies
33 CFR 164.74 Towline and terminal gear for towing astern

Additional Guidance:

API Specification 9A Specification for Wire Rope Section 3
ASTM D4268 Standard Test Methods for Testing Fiber Ropes
Cordage Institute CIA 3, Standard Test Methods for Fiber Rope Including Standard Terminations
NVIC 5-92 Guidelines for Wire Rope Towing Hawsers

The owner, master, or operator must ensure that the face wires, spring lines, and push gear used are:

  • Appropriate for the vessel's horsepower
  • Appropriate for the tow arrangement
  • Frequently inspected
  • Remain serviceable   

Items to check:

  • Face wires, spring lines & push gear appropriate, frequently inspected & serviceable.  

Regulatory Cites:

33 CFR 164.76 Towline and terminal gear for towing alongside and pushing ahead