SEEMP (Ship Energy Efficiency Management Plan) is part of MARPOL Annex VI (Regulation 22) and the IMO's approach to ship energy efficiency. Its parts:

• SEEMP Part I: the general plan (for all ships) - describes the methodology for improving the ship's energy efficiency (monitoring of fuel consumption, improvement measures such as speed optimisation, hull cleaning, trim, machinery optimisation, waste heat recovery, etc.). It is ship-specific and documents the "SEEMP" approach for the ship.
• SEEMP Part II (the CII/EEXI-based component, added under MEPC resolutions): sets a Ship Specific Carbon Intensity related to the required CII. It defines the ship's reference/required annual efficiency (CII), the attained CII to be monitored, and the individual improvement measures to meet the required CII. It is the operational component of the carbon-intensity regime.
• SEEMP Part III is the "SEEMP Part III" (under MEPC 328 etc.) which addresses the determination of the ship's operational carbon intensity (the CII) and the corresponding implementation - the actual operational data collection and the improvement plan to reach the required CII rating. More specifically, SEEMP Part III: (i) requires the ship to define/record a plan of practical measures to achieve its required CII (annual efficiency) and its target rating (improving each year), (ii) sets the "required" and "attained" CII (using the fuel oil/gso) and the improvement trajectory of at least the required annual reduction factor, and (iii) includes the mandated reporting (the actual attained CII to the IMO database via the flag/RO), the monitoring/verification, and the corrective/improvement actions if the rating is poor.

Objective: To reduce GHG (CO2) emissions from shipping by improving the energy efficiency of the operation, translating the technical efficiency (EEXI) and the required carbon intensity (CII) into an operational plan that is implemented, monitored and reported, with a continual improvement target each year.

Difference from Part I & II: SEEMP Part I is a general cross-cutting energy-efficiency framework/envelope (methodology, monitoring fuel, and measures); Part II aligns the ship's specific energy efficiency with the IMO CII/required carbon intensity and defines the reference lines/ratings; Part III is the operational implementation plan (the measures, targets and reporting rules) that puts the required "attained CII vs required CII" into practice, is updated annually with the attained data, and is mandatory/reportable, whereas Part I is an overall methodology not tied to a numeric annual target. (In practice the SEEMP as a single document covers Part I (framework) + Part II (CII/required intensity) + Part III (operational CII plan), with Part III being the specific operational/implementation section that becomes mandatory with the 2023 CII regime.)

• Fuel/energy data: accurately record the fuel oil consumption (bunker delivery notes, the fuel consumption log/EU-MRV or the IMO DCS method), the type and caloric values, and the ship's operational data (distance, cargo capacity, engine/operating time per the data collection system).
• Compute/verify the attained CII (the annual carbon intensity = total CO2/(capacity x distance), using the required data categories) and compare with the required CII for the ship type/year; keep these in the SEEMP Part III.
• Implement the operational measures: optimise speed/tune the engine, trim, hull/propeller cleaning schedule, propulsion efficiency (adjust pitch/RPM), improve dispatch & ballast handling, use waste-heat/improved auxiliary loads, and maintain the machinery (fouling, filters) to minimise fuel.
• Track and record the improvement measures and the monthly/quarterly consumption; calculate the attained CII at the end of the year.
• Retain the SEEMP Part III (with the annual updates), the attained CII and the supporting evidence (fuel data, voyage data, monitoring reports) for the verification by the RO/flag and for the SEEMP audit.
• Report the verified "attained CII" and required CII to the IMO Data Collection/MRV system (via the flag State and the RO D&A verification) within the prescribed deadline; the ship attains a CII rating (A to E) and must take corrective/improvement actions if the rating is poor (e.g. adjust the operational plan), and these are documented.
• Participate in the ship/engine energy management (coordinate with the Master/Chief Engineer) and ensure the crew are trained on the measures; maintain the records for PSC/flag/RO inspection.