3.8 Operational and planning manuals for ships engaged in anchor handling for which section 2.7 applies:
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Statutory Documents - IMO Publications and Documents - International Codes - 2008 IS Code – International Code on Intact Stability, 2008 - Part B – Recommendations for ships engaged in certain types of operations, certain types of ships and additional guidelines - Chapter 3 – Guidance in preparing stability information - 3.8 Operational and planning manuals for ships engaged in anchor handling for which section 2.7 applies:

3.8 Operational and planning manuals for ships engaged in anchor handling for which section 2.7 applies:

  3.8.1 To assist the master an operational and planning manual containing guidelines for planning and performing specific operations should be provided on board. The guidelines should contain sufficient information to enable the master to plan and operate the ship in compliance with the applicable requirements contained in this Code. The following information should be included as appropriate:

  • .1 anchor handling arrangements, including:

    • - detail arrangement of anchor handling deck equipment (winches, wire stoppers, towing pins, etc.);

    • - typical arrangement of cargo on deck (anchors, wires, chain cables, etc.);

    • - chain lockers used for mooring deployment;

    • - anchor handling/towing winch;

    • - tugger winches;

    • - stern roller, including lateral limits on both ends;

    • - lifting appliances, if any and if forming a physical restriction as per paragraph 3.4.2.10; and

    • - typical paths of wires between winches and stern roller, showing the limit sectors; and

  • .2 detailed data of the permissible tensions, stability limiting curves, and recommendations for calculating ship's loading conditions including sample calculations.

  3.8.2 An operation plan should be agreed to by the master of the ship and a copy archived on a remote location before the operation commences. Guidelines and procedures to define a step-wise operational plan for a specific operation should contain instructions for:

  • .1 identifying and calculating loading conditions for all relevant stages of operation, taken into account the expected fuel and stores consumption, alterations on deck load, effects of deployment or recovering of the wire on the winches and chain lockers;

  • .2 planning ballast operations;

  • .3 defining the most favourable consumption sequence and identifying the most onerous situations;

  • .4 identifying the possibility or prohibition of using the roll reduction systems in all operational stages;

  • .5 operation with open chain lockers, e.g. additional loading conditions for asymmetric filling or other measures to reduce the possibility of flooding;

  • .6 collect updated weather forecasts, and to define environmental conditions for anchor handling operations;

  • .7 the use of limiting stability curves and intended tensions;

  • .8 defining the stop work limits:

    • .a permissible tensions and operational sectors for α;

    • .b heeling angles in compliance with the stability criteria; and

    • .c environmental conditions;

  • .9 implement and define corrective and emergency procedures;

  • .10 define:

    • .a an operational zone in which normal operations up to the permissible tension are to occur (i.e. a "Green" zone);

    • .b a cautionary zone (i.e. a "Yellow" or "Amber" zone) where operations may be reduced or halted to assess the ship's options to return to the operational or Green Zone: the cautionary zone should be not less than an angle of 10 degrees unless table 3.8.3 provides otherwise; and

    • .c a "Stop work" zone (i.e. a "Red" zone) in which the operation should be stopped, for which, in normal operations, the yellow/red boundary should not exceed 45 degrees or the point at which the wire rises above the deck. Notwithstanding this, due consideration may be given to different operations from typical anchor handling operations where the planned operation ensures the safety of the ship; and

  • .11 examples of presentation of permissible tensions are presented in annex 3 to part B.

  3.8.3 To aid the definition of permissible tensions and zones based on the availability of tension monitoring and an onboard stability instrument the following table is provided.

Table 3.8.3

Availability of Tension Monitoring and an onboard Stability Instrument Tension monitoring is not available Tension monitoring is available but no stability instrument is available Both tension monitoring and a stability instrument is available
Permissible tension, Fp Design Maximum Line Tension, Fp, in the operational zone. Fp as described in Stability Booklet, the operational planning guidelines, or the specific operational plan. Fp as calculated by the Stability Instrument for the actual loading condition.
Permissible table First α should be 5°. The only permissible tension is the Design maximum wire Tension, Fd. Figures in the table will be Fd for α for which Fp ≥ Fd. The cautionary zone would include positions where Fd > Fp ≥ maximum winch wire pull. The stop work zone is every other position where Fp < the maximum winch wire pull. If criteria is not fulfilled at α = 5° anchor handling should not be performed without winch modification. Tables may be prepared for different values of draft, trim, KG or GM, or specific predefined loading conditions. Values in the table should range from α = 0 to α = 90º. A table should identify Fp at critical points and the table should be provided for each set of towing pins. Tables or curves provided in the stability booklet may be used where Fp throughout the nonspecific operational zone exceeds the maximum anticipated wire tension; otherwise, tables or curves calculated for the actual loading condition must be developed.
Zones The operational zone should be defined as the sector between the two outboard α values for which Fp≥ Fd.

The cautionary zone should be defined as the sector between the α at which Fp = Fd and α at which Fp = maximum winch wire pull.

The stop work zone should cover every other position. The sectors should be documented in the Stability Booklet, the operational planning guidelines, or the specific operational plan. The sector diagram may be prepared for multiple loading conditions. If the limiting α is less than 5° anchor handling operations should not be performed without winch modifications.

The zones may be developed based on normal operational practices contained in the operational planning guidelines, e.g. the operational zone on the stern roller, cautionary zone for not more than 15deg past the stern roller and the red zone otherwise or developed for a specific operation where the outboard α values at which Fp = maximum anticipated wire tension minus 10º defines the operational zone, if α is greater than 20º. If this α is less than 20º, the operational zone is defined as the sector between ½ the outboard α values at which Fp = maximum anticipated wire tension. In each case, the cautionary zone is defined between the limit of the operational zone and the α value at which Fp = maximum anticipated wire tension. In each case, the operational zone must be identified for the anticipated wire tension. The zones may be developed based on normal operational practices contained in the operational planning guidelines, e.g. the operational zone on the stern roller, cautionary zone for not more than 15deg past the stern roller and the red zone otherwise or developed for a specific operation where the outboard α values at which Fp = maximum anticipated wire tension minus 10º defines the operational zone, if α is greater than 20º. If this α is less than 20º, the operational zone is defined as the sector between ½ the outboard α values at which Fp = maximum anticipated wire tension. In each case, the cautionary zone is defined between the limit of the operational zone and the α value at which Fp = maximum anticipated wire tension. In each case, the operational zone must be identified for the anticipated wire tension.
Parent topic: Chapter 3 – Guidance in preparing stability information
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