HomeCalculatorsSEEMP Combined Operational Measures

SEEMP Combined Operational Measures

Stack the percentage fuel-saving contributions of multiple SEEMP Part III operational measures using the standard non-overlapping (multiplicative) formula. Returns combined fuel saving, equivalent CII improvement, and annual cost saving in USD at a user-set bunker price.

SEEMP Part IIICIIOperational

Operational measures

Set the expected percentage saving for each measure. Use 0% to exclude. Defaults reflect typical industry case-study ranges; adjust to ship-specific evidence.

Slow steaming% savingCubic relationship: 10% speed reduction ≈ 27% main-engine power reduction. Typical SEEMP target: 8–15% fuel saving.Weather routing% savingLong-distance ocean voyages: 2–5%. Seasonally challenging routes (winter North Atlantic): 5–10%.Hull cleaning + propeller polishing% savingRecovers 80–90% of biofouling-driven resistance penalty. Typical 6–12 month cycle: 5–8% saving.Trim optimisation% savingReal-time trim software (NAPA, Eniram, FORCE). Typical saving: 1–4%.Just-in-time arrival% savingCoordinated arrival at pilot station. Typical saving: 2–7% depending on trade pattern and waiting time at destination.Fuel switching to lower-WtW fuel% savingEquivalent CII improvement from switching part of fuel mix to a lower-Cf fuel (e.g. B30 biofuel blend ≈ 30%, full bio-MGO ≈ 95%). Use the GFI Attained calculator for precise WtW figures.Energy-saving devices% savingPre-swirl stators, propeller boss cap fins, ducts, Mewis ducts. Typical retrofit saving: 2–5%.Other measures% savingCargo heating optimisation, shore power at berth, shaft generator, waste heat recovery, etc.

Baseline and pricing

Baseline annual fuel consumptiont/yrTotal annual fuel mass before measures, from IMO DCS report or commercial estimate.Bunker priceUSD/tReference fuel price for the cost-saving calculation. Typical 2025 VLSFO Singapore: ~USD 580/t.

Combined fuel saving

22.0%

5 measures stacked.

Annual fuel saved

2,197t/yr

Annual CO₂ saved

6,843t CO₂/yr

Using Cf = 3.114 t CO₂/t fuel (HFO).

Annual cost saving

1,274,536USD/yr

Formula, assumptions, and limits

Non-overlapping multiplicative combination of fractional savings. Assumes the measures act on the same baseline fuel consumption with no double-counting. Where measures interact (e.g. slow steaming reduces the absolute saving from weather routing), this formula slightly underestimates the combined effect; for measures that are mutually independent, it is exact.

Symbol legend

Symbol	Meaning	Unit	Source
	Fractional fuel saving from measure i	fraction	IMO MEPC.346(78) typical ranges
	CO₂ conversion factor for HFO	t CO₂ / t fuel	3.114, MEPC.364(79)

The combined saving is reported as the equivalent percentage reduction in attained CII; the ship's actual CII rating depends also on the Required CII for the year and the rating boundaries of MEPC.339(76).