Yacht Sea Trial Guide

The purpose of a sea trial

A sea trial confirms how the yacht behaves under way. A survey establishes condition at rest; the trial tests machinery, systems and handling under load, which is where several classes of defect only become visible.

Like the survey, the trial is normally a stated condition of the memorandum of agreement, conducted before the buyer accepts the yacht.

What is usually observed

The programme is agreed in advance with the captain, the surveyor and the buyer's technical representative.

• Engine performance across the rev range, including sustained cruise and maximum continuous rating.
• Temperatures, pressures and alarm behaviour under load.
• Manoeuvring, steering response, thrusters and anchoring.
• Stabiliser performance at anchor and under way, where fitted.
• Noise and vibration levels in guest and crew areas.
• Navigation, autopilot and communications equipment in live use.
• Generator load sharing and electrical stability with systems running.

Who runs it

The yacht remains under the command of her captain and crew throughout. The buyer's surveyor and superintendent observe and record; the buyer and broker normally attend. Trials are constrained by weather, sea state, fuel state and safe operating limits, and the captain's judgement governs the programme.

How results affect the transaction

Observations are recorded and read together with the survey report. Machinery faults, excessive vibration, alarm conditions or performance materially short of expectation are the items that conventionally lead to further inspection, a works list or renegotiation.

Where a fault cannot be assessed in the available conditions, the usual route is a further trial or a targeted inspection rather than an assumption either way.