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

Changing the inputs requires JavaScript. The calculator above shows its default inputs and result. The formula, symbols, and regulatory sources are shown in the Formula section below.

Formula, assumptions, and limits

\text{Combined saving} = 1 - \prod_{i} (1 - s_i)

Symbol	Meaning	Unit
$Combined saving$	Combined fractional fuel saving from all measures	fraction
$s_i$	Fractional fuel saving from measure $i$	fraction
$\prod_i$	Product over all measures $i$

Source: IMO Resolution MEPC.346(78) - 2022 Guidelines for the Development of a Ship Energy Efficiency Management Plan (SEEMP); IMO Resolution MEPC.328(76) - Amendments to MARPOL Annex VI introducing SEEMP Part III; IMO Resolution MEPC.364(79) - Cf fuel conversion factors; ICS SEEMP Guide (4th edition, 2023); BIMCO CII Clause for Time Charters (November 2022); DNV Maritime Forecast to 2050 (2025 edition)

In short

Stack the percentage fuel-saving contributions of multiple SEEMP Part III operational measures and report combined fuel saving, CO₂ saving and USD cost saving.

Learn the theory BIMCO CII and Emissions Clauses