Biofouling management plan
The plan and record book under the 2023 IMO Biofouling Guidelines: the four-level fouling rating, idle-time provisions, and the charter party interface.
A biofouling management plan is the ship-specific document describing how accumulation of aquatic organisms on the hull, propeller and niche areas will be prevented, monitored and managed, together with a biofouling record book evidencing what was actually done.
The governing instrument is resolution MEPC.378(80), the 2023 Guidelines for the control and management of ships biofouling, adopted 7 July 2023, which replaced the 2011 guidelines. It introduced a four-level fouling rating system and set out expectations for the plan’s content, the record book and the inspection regime. The framework is condition-based: cleaning follows the assessed fouling rating and the operating profile rather than a fixed calendar.
The provision with the widest commercial reach is idle time. Acceptable idle time is a plan parameter, typically in the range of 18 to 30 days, and it is frequently written into charter parties, which makes it a negotiated term rather than only a technical one. Because a slow-steaming or waiting ship accumulates idle time faster, the plan and the commercial position interact directly. The full article will cover plan content, the record book, niche areas, port and flag state expectations and in-water cleaning. See slow steaming and hull roughness and added resistance .