Trim Optimisation

A slight bow-down or bow-up trim shifts the wetted surface and pressure field; the optimum trim at a given speed and loading condition typically saves 1–3 % of propulsion fuel. This tool estimates the saving from the trim-vs-resistance curve slope.

OpsTrim

Baseline

ME fuel rate at even-keel referencet/dayHours / year at seahFuel

Trim benefit

Resistance reduction at optimum trim%Tanker at design draft 1–2 %; container at partial draft 2–4 %; ro-pax 1–2 %. Larger at part-load.Share of voyage hours where optimum trim is practical%Cargo operations, safety, and port stability limits reduce coverage.

Fuel saved / year

118.1t

CO₂ avoided / year

367.8t

Formula, assumptions, and limits

Trim curves come from CFD or model-basin tests at 2–3 drafts × 3–5 speeds. Onboard decision-support tools (Kongsberg K-Trim, NAPA Loading Computer, Eniram Trim) interpolate the curve in real time based on current draft/speed.