Weather Routing Savings

Optimised track selection through varying wind/wave/current fields instead of rhumb-line or great-circle. Fleet-average savings 2–5 % on trans-ocean legs; higher on wind-driven trades like North Atlantic or South Pacific crossings.

OPSWeather

Baseline voyage

Great-circle distancenmME fuel rate at reference speedt/dayReference speedkn

Routing benefit

Average fuel reduction from routing%Trans-ocean 2–5 %, monsoon trades 4–7 %, coastal 0.5–1.5 %.Extra distance accepted to avoid weather%Typically 1–3 % extra nm for a 4 % fuel saving.Fuel

Baseline fuel: 1,116.1t

Routed fuel: 1,092.9t

Net fuel saved: 23.2t

2.1 %

CO₂ avoided: 72.3t

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

F_\text{routed} = F_\text{base} \cdot (1 - p_\text{save}) \cdot (1 + p_\text{extra})

Symbol	Meaning	Unit
$F_\text{base}$	Fuel on the rhumb/great-circle route at reference speed	t
$F_\text{routed}$	Fuel on the optimised route	t
$p_\text{save}$	Fractional fuel reduction from avoiding weather	fraction
$p_\text{extra}$	Fractional extra distance accepted	fraction

Source: StormGeo - *Ship Routing Services*; ECMWF - high-resolution atmospheric model; IMO Resolution MEPC.282(70) - SEEMP weather-routing guidance

In short

Net fuel and CO₂ saving from weather-routed tracks, accounting for extra distance accepted to avoid adverse weather.

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