Mooring System Management Plan (MSMP) & Line management plan (LMP)

Standard Mooring System Management Plan (MSMP)
The MSMP should be written to ensure the mooring system is inspected, maintained and operated in
accordance with the original design basis. The information contained should be available to anyone who
needs to review it. The MSMP does not need to be a comprehensive plan incorporating all information, instead
it could be a framework document that links to the information held elsewhere in the ship’s records or Safety
Management System (SMS). The following guidance is written to provide assistance in writing a comprehensive
and complete plan. OCIMF created the MSMP on the basis of the standard International Maritime Organization
(IMO) approach of setting a goal and then listing the functional requirements for how to achieve this.
Line Design Break Force – (LDBF)
This is the minimum force that a new, dry, spliced mooring line will break at when tested according to appendix
B. This is for all mooring line and tail materials except those manufactured from nylon which is tested wet and
spliced. This value is declared by the manufacturer on each line’s mooring line certificate (see appendix B) and
is stated on a manufacturer’s line data sheet. As outlined in appendix B, when selecting lines, the LDBF of a
line shall be 100-105% of the ship design MBL.
The LDBF for nylon (polyamide) mooring lines should be specified as break tested wet because nylon lines
change strength characteristics once exposed to water and generally do not fully dry to their original
construction state.
Working Load Limit – (WLL)
This is the maximum load that a mooring line should be subjected to in operational service, calculated from
the standard environmental criteria. The WLL is expressed as a percentage of Ship Design MBL and should
be used as a limiting value in both ship design and operational mooring analyses. During operation, the WLL
should not be exceeded.
In the same way that SWL is a limit for fixed equipment, the WLL value is used as a limit with the standard
environmental criteria and mooring layout when designing mooring systems in establishing mooring system
designs. Steel wire ropes have a WLL of 55% of the Ship Design MBL and all other cordage (synthetic) have a
WLL of 50% of the ship design MBL.
Tail Design Break Force (TDBF)
The TDBF needs to be higher than the LDBF because tails experience more wear in service than lines. The TDBF
of tails should be 125-130% of ship design MBL. TDBF is tested and defined in wet condition (see testing
guidance outlined in appendix B of MEG4) and accounts for any material strength loss when wet.