- Any alterations affecting a ship’s lightship properties require updated stability information per SOLAS Chapter II-1, Regulation 5.4.
- If modifications exceed 2% in lightship displacement, 1% in the longitudinal center of gravity (LCG), or 1% in the vertical center of gravity (VCG), a new inclining test and stability reapproval are required.
- Shipowners must maintain a record of alterations and submit recalculated stability information and supporting documents to Lloyd’s Register for appraisal.
Lloyd’s Register (LR) has issued Class News 08/2025, highlighting the stability information requirements for ships undergoing alterations that affect their lightship properties. According to SOLAS Chapter II-1, Regulation 5.4, any modifications that materially impact a ship’s stability necessitate the provision of updated stability information to the master.
Applicability
This regulation applies to all ships covered under SOLAS Regulation II-1/5.4, irrespective of their construction date. Shipowners, operators, managers, masters, designers, and builders must ensure compliance.
New Inclining Test Requirements
A new inclining test and reapproval of stability information are mandated when alterations result in deviations exceeding:
– Lightship displacement (lightweight) by more than 2%.
– Longitudinal center of gravity (LCG) by over 1% of the ship’s length (L).
– Vertical center of gravity (VCG) by more than 1%.
Recalculation and Reapproval
If the deviations are between:
– 1% and 2% for lightship displacement.
– 0.5% and 1% of L for LCG.
– 0.5% and 1% for VCG.
Then, stability information must be recalculated and reapproved using the new lightship properties.
Record of Alterations
Ships must maintain a record of all alterations and associated deviations in lightship properties. This record should be kept with the approved Trim & Stability Booklet onboard and account for cumulative changes over time.
Submission to Lloyd’s Register
When alterations occur, shipowners must submit detailed calculations and supporting evidence to LR for appraisal. This includes reports on weight changes, updated lightship particulars, manufacturer datasheets, drawings, and the latest approved stability information.
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Source: Lloyd’s Register
