Sea Trials

The sea trial is one of the most misunderstood processes in boat purchasing and ownership.  It is the only opportunity for both manufacturers and you as an owner to determine if a vessel is performing up to its design specifications.

A proper sea trial involves a thorough understanding of a boat’s systems and a prescribed approach to exercise these systems and the boat as a whole.  The most common sea trials are prior to purchase or after major work, usually commissioned by the prospective buyer or owner to ensure that the vessel performs up to specs, and to uncover any flaws in how the vessel and its systems perform underway.

Sea trials are not the time to baby the boat – instead, only by exercising all parts and systems to their design intent will you know that you are not masking a hidden problem that might manifest itself off a lee shore at midnight.


Bay Vessel Services has extensive experience with sea trials of motor and sailing vessels, and I apply a unique blend of operations and engineering expertise which gives you an honest and rigorous evaluation.  I have developed detailed sea trial protocols for power and sailboats which are used to guide through the entire process.

It is highly recommended that you include a fully qualified mechanic in the sea trial process to verify compliance with installation guidelines prescribed by the manufacturers for all major components and running gear.

A thorough sea trial consists of the following basic steps – this is not an all inclusive protocol:

  • Vessel is prepared for sea, with gear stowed and tanks filled to verify performance numbers, and all legal requirements met.
  • Mechanical checks of all fluids, and inspection of all components for proper installation and suitability for service.  This includes main engines, generator, bow thruster, steering, and all ancillary systems.
  • Check of all navigation and electronics systems.
  • Cold start of engines one at a time, and record ease of starting, charging status, engine parameters, and all alarms.
  • Initial load testing under moderate load, recording all parameters and checking temperatures of exhaust components, checking for vibration, alignment issues, leaks and overall system operation.
  • Record all system parameters at increasing loads in a systematic manner, checking fuel consumption, and recording temperatures of all components (engine parts, gearbox, stuffing box, thrust bearings, etc) utilizing an infrared spot thermometer.  Also verify that engine room and air intake temp meets manufacturer specifications.
  • Steering test hard-over, checking for proper operation of hydraulics, power steering units, rudder posts, tillers, tie rods, clevis pins, and other items.
  • 100% load test – this is often a skipped item with the belief that it is abusive to the boat and engines.  Nothing could be further from the truth – all marine engine manufacturers publish and certify for operation at a specific RPM at wide open throttle.  This test confirms the engines are operating to specifications and are properly mated to propellers of the right pitch that are not overloading (or underloading) the engines.
  • Backing test – confirmation that the engine does not stall and thrust bearings and engine mounts behave as designed under astern thrust.
  • Check of generator under full load with all systems running (air conditioning, reefer, etc).
  • Check of windlass and other ancillary boat systems.
  • Throughout the process, verify that there are no unusual flexures, noises, smells, water entry, odd handling behavior or other unexpected items.
  • Sailing vessels also include performance with all combinations of sailplan on multiple masts, ability of winches (manual and electric) to handle loads, tankage behavior under various heel angles, and other tests unique to sailing vessels.
Let Bay Vessel Services assist you with your sea trial needs – you will receive professional, unbiased, and very thorough evaluation and documentation of your boat’s performance.