PassageMaker - April 2012

Conduct a dockside, visual inspection of the vessel’s key systems, particularly running gear, including the engine and transmission fluids, stuffing box, gearshift and throttle components, shaft coupling, exhaust system, and steering gear. Be sure to look under engines and generators and note (and photograph if you can) any accumulation of oil, coolant, or other fluids. You’ll return to this area after the trials are complete for a comparison look.

Ensure that engine alarms operate. Typically, this can be done by turning the keys or ignition switches to the “on” position without starting the engines. A low oil pressure alarm should chirp or sound continuously. If you hear nothing, it’s possible the engines are operating without low oil pressure or high water temperature alarms. Without them, there will be no warning to an impending overheat or catastrophic loss of oil pressure, either of which could cause rapid, irreparable, and costly damage to the engines.

For pre-purchase sea trials, in advance of the established trial date ensure that a qualified individual, typically the broker or a designated captain, will be present to operate the vessel. You should not operate the vessel except under their watchful eye and only when sea room permits, especially if the waters are unfamiliar to you. If you already own the vessel and she’s being tested after refit or repair work, the yard that carried out the work should run the vessel with you aboard.

Each and every system that could or might ever be operated while under way should be operational and should be checked. This includes, obviously, main propulsion engines; however, it also includes the wing engine and the generator. The former should be operated to propel the vessel for a minimum of 10 to 15 minutes, as well as the generator. Engines should be cycled through gear positions several times to ensure proper operation of controls and transmissions. Additionally, a back-down test should be performed. More on that in a moment.

Generators should be run, while under way, to at least 50 percent and preferably at or above 80-percent load. Doing so ensures that they are capable of carrying and sustaining a heavy load that is not hindered in any way by vessel motion and they add heat to the

engine room for a more thorough, real-world test. Include in the “run list” watermakers, and of course, all navigation electronics, radar, depth finders, plotters, etc. If the sea trial is being carried out to test a specific installation or repair, a new or repaired turbocharger, heat exchanger, or running gear component, then emphasis should be placed on this equipment specifically and it should be closely monitored during the trials.

One of the more important and often overlooked aspects of a sea trial is temperature monitoring, specifically the temperature of the air being drawn into the engines and generators. Don’t confuse this with the temperature of the engine room. While that’s important in its own right, it is not as easily quantifiable as the intake air temperature and there is not a clearly defined mandate for its limits. The cooler an engine room operates, the better off all of the gear and equipment that lives there will be, particularly “soft” items like motor mounts, hoses, insulation, and electrical components.

Most engine manufacturers specify
a maximum differential temperature
between the air their engines
consume and the air outside the
vessel, often referred to as the delta
Such documents are available for most engines, even
those no longer manufactured. Don’t rely on others to
provide this information or recite it from memory, as
even professionals make mistakes. Going into a sea trial
without this document is tantamount to flying blind.

The conditions under which a vessel is trialed can have a significant impact on how she performs. Most vessels, even those that are poorly found and ill maintained, will perform acceptably in glassy calm conditions. If she’s a vessel that’s designed for bluewater, offshore passagemaking, then she should be tested

Among the most valuable arrows in your sea-trial quiver, an infrared pyrometer will enable you or a professional to analyze the operation of a variety of components, from exhaust systems to stuffing boxes.