In March 2024, the IMO adopted MEPC.390(81), an amendment to MEPC.335(76), providing guidelines on the shaft/power limitation system for EEXI compliance. These guidelines now mandate updating the maneuvering characteristics for situations when shaft or engine power has been limited, reports DNV.
Key Points
Applicability:
- It is relevant for ship owners and managers of ships above 400 GT with power limitations for EEXI compliance and flag states.
Documentation Requirements:
- Wheelhouse Poster, Pilot Card, and Manoeuvring Booklet:
- The impact of the overridable power limitation on maneuvering capabilities is marginal. However, according to IMO Res, the power limitation must be indicated on the maneuvering information display. A.601(15).
- DNV recommends updating the propulsion particulars on the existing wheelhouse poster. Highlighted parts of the table should reflect the new values with EPL/ShaPoLi. Original values should remain visible but struck through.
- The same updates are required for the pilot card and maneuvering booklet.
- Submission to DNV is needed only for ships with additional class notation NAUT(AW). Non-compliance with updated documents might lead to the vessel being considered non-compliant by the U.S. Coast Guard under 33 CFR § 164.11 (k).
Nautical Manoeuvres and Track Plots:
- If new trials were conducted after installing the power limitation, nautical track plots should be revised in the wheelhouse poster.
- There is no requirement for new tests post-installation; estimation of maneuvering characteristics is acceptable, with some obtained from trials per IMO Res. A.601(15).
- Nautical maneuvers include turning circles with a hard rudder, inertia, crash stop, Williamson turn, and zigzag tests as described in MSC/Circ.1053.
Class Approval:
- Granted only for ships with additional class notation NAUT(AW). Test procedures must be submitted for approval before performing new maneuvers.
Crew Recommendations:
- Crew should:
- Provide clear information to pilots about the power limitation and updated maneuvering information.
- Be familiar with procedures to release the power limitation for using the power reserve.
Additionally, comparing the load diagram from the main engine EPL report or manufacturer’s project guide with the lever setting table is advised. This helps determine RPM values for stable and transient operations, ensuring optimal engine behavior.
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Source: DNV
