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TB 55-1900-232-10
The purpose of this appendix is to establish the requirement for towing ships to keep a Towing Hawser Log .
Entries in this log will be useful in the evaluation of past hawser usage and will assist in evaluating the present
condition of the hawser and in the decisions concerning replacement.  The log provides a documented
reference for the Commanding Officer's use in evaluating the condition of readiness of the hawser The
condition of the hawser may not be apparent, even to the experienced operator, and thus the record of usage
may become a decisive factor in evaluating operational readiness and overall system safety. This appendix
replaces the NAVSEAINST 4740 series regarding hawser logs.
Historically, there have been fewer towline component failures on ships where close attention has been paid to
the condition and history of the hawser and other tensile components of the towline. Life of towline components
depends less on age than on care, use and history of failures. Fiber lines of all types, including natural and
synthetic fiber, deteriorate with age, shelf life and usage The fiber core m wire ropes, particularly if it is natural
fiber, also deteriorates with age. Old wires and those with no documentation should be treated with suspicion
In some instances when hawsers and other components fail, it has been impossible to ascertain usage,
manufacture and installation data because a log had not been kept. This lack of data precluded a meaningful
analysis of the failure.
NSTM 613 (Ref. 15) describes the fabrication, conditions of use, care and preservation of wire rope, fiber rope
and cordage . Additionally, the Wire Rope Users' Manual (Ref. 13), as well as handbooks and catalogues
published by major wire and rope manufacturers, are useful.
Keeping a hawser log is mandatory for all towing ships Selection and identification of other components that
should be similarly logged and administered is left to the discretion of the Commanding Officer. In general,
ships may find it beneficial to keep a similar log on mooring lines. Salvage ships may also find it prudent to
keep logs on beach gear components, chain and connecting hardware.
Salvage ships, fleet tugs, submarine rescue ships and other Navy ships which normally engage in towing
operations must maintain a Towing Hawser Log m the format of Attachment A to this appendix. Ships may
also keep similar logs on other towline components.
The log should record a comprehensive history of all towing hawsers on the ship. This includes the main wire
rope hawser and target towing hawsers.
It is the responsibility of the command to maintain the log . Periodic review is mandatory.
Type Commanders should include the requirement for keeping hawser logs as a check-off item in their
Operational Readiness and Administrative Inspection Lists.
Ships experiencing failure of hawsers and other logged towline components should advise NAVSEA (Attention
SEA OOC and SEA 56W), giving details which may be needed for technical evaluation. Fifteen-year-old
hawsers are definitely suspect
Whenever a hawser or other logged component breaks under suspicious conditions, save the


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