Watch one crane work a 40-ft bay: deck boxes, hatch covers, then the hold. Head trucks (HT) feed the crane from the lane underneath, so short-handed trucking shows up as crane idle time.
Trucks run parallel to the berth, stop under the crane, then return to the yard. The boxed bay is the one shown in the elevation.
Model assumptions: trolley 240 m/min; hoist 180 m/min with the empty spreader, falling linearly with weight to 90 m/min at 40 t; 0.8 m/s² acceleration on both, final 1.5 m spotted at 24 m/min, 5 s to lock and 5 s to unlock. Hoist and trolley run together: the trolley starts once the load clears neighbouring stacks, and lowering starts as early as the path allows, giving the arc shown as a dashed line. Inside the hold the load moves only vertically (cell guides). The load hangs as a simple pendulum from the trolley, θ″ = −(g/L)·sinθ − (a/L)·cosθ − 2(L′/L)·θ′ − damping, and the operator waits until sway is under 8 cm before landing. A skilled operator (anti-sway off) does two things: spreads trolley acceleration and braking over one full swing period, so the swing set up at the start cancels by the end, and catches any remaining swing by inching the trolley after the load, which moves the rope's pivot under it and drains the swing in a period or two instead of many. Collisions use the exact box, hatch, bulwark, lashing-bridge and truck outlines: a swinging load that touches something rebounds (restitution 0.3) and the contact is counted if it hits faster than 5 cm/s; a hoist or trolley motion that would push the load into something is stopped until the swing dies down. In the hold the cell guides hold the box to its 15 cm clearance. In manual mode the trainee drives trolley and hoist with a spring-return master controller (full or creep speed), and the twistlocks only turn when the spreader is landed within 15 cm of the target. Each move is scored out of 100: time over par (the auto operator's motion time plus a 10 s allowance; waiting for an HT is not counted), offset beyond 5 cm, firm (over 0.4 m/s) and hard (over 0.7 m/s) landings, and impacts. Each 40' box has a tare (3.7–3.95 t dry, 4.5–4.8 t reefer) and a gross weight up to the 30.48 t limit; hatch cover panels weigh 26 t. The vessel floats by Archimedes' principle: taking weight off raises it by weight ÷ (seawater density 1.025 t/m³ × 7,350 m² waterplane), about 1 cm per 75 t, with a heave period of 8 s. Weight off the centreline heels it until displacement × GM (1.3 m) × tan φ balances the moment, with a 22 s roll period; ballast control pumps up to 9,600 t·m/h across the heeling tanks. The crane follows its landing as the ship moves. Bay 26 has 11 rows (port side to quay) with 6 tiers in the hold and up to 5 on deck. Slot codes are bay·row·tier.