Sea Trial

A sea trial tests the machinery, steering, navigation electronics and deck gear on the water and under load. Most of the defects that stay hidden during an inspection ashore surface at this stage. It takes about half a day.

The boat on paper, the boat at sea

Brochure figures and dockside inspections describe a vessel’s potential. The sea tells its truth: what the engine does under load, how the hull meets a wave, what the helm transmits to your hand. The sea trial is the survey’s final and most revealing examination.

What is measured underway

The main engine and generator run through the rpm range, with speed and consumption tabled at each step — a boat that misses its expected speed is pointing at anything from propeller mismatch to hull fouling, and the cause is assessed. Turns at low and high speed, astern handling, crash stop and course changes record steering response and play. Noise is measured in the saloon and master cabin at each speed and charted; vibration from the shaft line is measured, since growth out of proportion to rpm flags alignment or bearing wear. Throughout the trial, Jaltest diagnostics stay connected to the engine — injection data, turbo pressure, exhaust values, sensor calibrations and the fault-code history that independently checks the seller’s maintenance story. The engine, exhaust run, shaft bearings and panel are also scanned under load with the thermal camera, and the navigation electronics are verified live.

What sets the trial apart

In most sea trials the engine is judged from the gauges and by ear. We leave the diagnostic tool connected throughout the trial and log the engine’s own data: rail pressure, boost, exhaust and coolant temperatures, cylinder contribution balance, fuel rate.

Instead of “she ran up fine, no problem”, you get the temperature the engine actually reached at full load and which cylinder fell behind — as numbers. The person taking those readings is also a qualified marine mechanic and master instructor.

The report

Measurement tables, charts and the Jaltest printout support an assessment of the vessel across safety, performance and comfort — as part of a pre-purchase survey or as a standalone test.

Duration and fee

A sea trial takes about half a day, and the engine sea trial is included — a trial is not complete until the engine has been measured under load.

Fees vary with the length of the boat, where she lies and the season. For a firm price call us — tell us about the boat and we will give you the number on the phone.

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