Just-in-Time Arrival

Quantify fuel and CO₂ avoided by reducing speed on a leg so that the ship arrives at the pilot-station at the agreed time instead of steaming flat-out and then waiting at anchor.

VoyageJITPort call

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This calculator requires JavaScript to compute its result. The formula, symbols, and regulatory sources are shown in the Formula section below.

Formula, assumptions, and limits

V_\text{jit} = \frac{D}{D / V_\text{full} + t_\text{wait}}

Symbol	Meaning	Unit
$V_\text{jit}$	Speed that arrives exactly at the agreed slot	kn
$V_\text{full}$	Speed the ship would have steamed without JIT	kn
$D$	Distance to pilot station	nm
$t_\text{wait}$	Anchor/standby time that JIT eliminates	h
$\text{ME}_\text{full}$	Main-engine daily fuel rate at $V_\text{full}$	t / day
$n$	Speed exponent (≈ 3)
$\Delta F$	Fuel avoided	t

Source: IMO MEPC.323(74) - voluntary port-ship cooperation; GloMEEP / IAPH - *Just-in-Time Arrival Guide*

In short

Quantify fuel and CO₂ avoided by matching speed to the agreed pilot-station slot instead of waiting at anchor.

Learn the theory Voyage Estimation: TCE, Bunkers, and Canal Economics