MOORING SYSTEM MANAGEMENT PLAN
(MSMP):The vessel shall maintain all ship’s specific data in MSMP.The objective for the MSMP is to ensure that all assessed risks are effectively managed through the design and operation of the mooring system.
Its aim is to ensure that during mooring operations, no harm comes to ship or terminal staff or damage to the ship or terminal/ facility it is interfacing with, and that the mooring system meets applicable regulations, codes and recommended practice.
The MSMP contains details of items that may be ship or operator specific (e.g. parts of the operator’s SMS), and guidance on items that should be retained in a Mooring System Management Plan Register (MSMPR) that stays with the ship throughout its life-cycle.While all new ships after MEG-4 came in force should be able to achieve all parts of the MSMP structure, existing ships may experience limitations particularly in accessing original design information.
It is recommended that existing ships undertake the necessary due diligence to collate required information or align their operating practices with these fundamental safe mooring principles, so far as it is possible and practicable.
LINE MANAGEMENT PLAN (LMP):
The vessel shall maintain all ship’s specific data in LMP.It will have a program for line maintenance, inspection, retirement and end-to-end policy.
Thia aim is to reduce unnecessary degradation of the lines and ensure lines are operated within safety margins over their service life. The LMP contains the Company’s requirement for the management of mooring line maintenance, inspection and retirement during the operational phase of the mooring line life-cycle.
In Shipping industry, we were so used to the terms such as MBL, BHC, BRC, SWL. Hence, new terms such as Ship design MBL, LDBF, WLL, etc. which came in being from MEG 4 may make us somewhat confused.
Of course, the intent is good, however it will take some time for users to understand these new terms and the intent of OCIMF.
Following is a simplified version of clarifications provided by OCIMF :
Why is OCIMF replacing “MBL”with new terms such as Ship Design MBL (MBLSD), Line Design BreakForce (LDBF), and Working Load Limit (WLL)?
a) To bring uniformity in the terms used by Rope manufacturing industry and Tanker Shipping industry.
b) Specifications and references used by rope manufacturers were different and were likely to have differences greater than 10% between Line Design Break Force and MBL.
c) The term ‘Minimum’ Breaking Load” was giving rise to the misunderstanding that lines can be safely loaded up to their MBL with no failures or degradation. This is not the case and OCIMF has now tried to heighten the understanding of the importance of safety margins on mooring lines.
What is Ship DesignMBL?
The MBL of new, dry mooring lines for which a ship’s mooring system is designed, to meet OCIMF standard environmental criteria restraint requirements.
The ship design MBL is the core parameter against which all the other components of a ship’s mooring system are sized and designed with defined tolerances.
Yard is required to provide this for new ships. If not provided for existing ships, Vessel should follow the same guidance of setting the winch brake rendering values based on the “line MBL”originally provided by yard and assumed to be synonymous with Ship design MBL,which is termed “Design Rope” MBL .
What is the LDBF?
LDBF is almost similar to the term MBL of lines used previously. However, LDBF is the term used in rope certificate and it is an accurate figure without any discrepancy. When selecting lines, the LDBF of a line shall be100%–105% of the ship design MBL.
It is minimum force that a new, dry spliced mooring line will break at when tested as specified. This is for all mooring lines and tail materials except ones manufactured from nylon which is tested wet & spliced.
What is WLL?
WLL is like SWL of the lines. It 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. When vessel is moored, the WLL should not be exceeded. Steel wire ropes have a WLL of 55% of the ship design MBL and synthetic ropes have a WLL of 50% of the ship design MBL.
What should be BRC which used to be 60% of mooring line MBL?
The BRC should be set to 60% of the ship design MBL. The lines will be having a force of WLL at all times i.e. 50 to 55% of Ship design MBL.
But it will not cause brakes to render.If force increases to 60% of Ship design MBL, brakes will render to protect all parts of the mooring systems. The rendering point is below all other failure loads but above line WLLs.
The mooring winch brake becomes a weak link within the mooring system.
What data to give if anyone asks for mooring line MBLs?
The Ship should answer this query by providing with both, i.e. ship design MBL and LDBF values referencing alignment to MEG4. Is there any change in mooring tails?Yes. Mooring tails certification will also follow same pattern as mooring line and it will also mention LDBF and all mooring tails are required to have LDBF 125-130% of ship design MBL i.e. 125% of line’s LDBF as before.