A sea trial is a testing phase for a ship to ensure its seaworthiness. Sea trials are conducted after new construction, major repairs, or when a ship has been in dry dock. These tests are performed to check the safety, reliability, and performance of a ship. A shakedown cruise is another name for a sea trial, because the ship will be pushed to its limits during the test.
Sea trials begin with the initial start up and evaluation of the various operating systems aboard a ship. This testing often occurs while the vessel is still pier side and technically not at sea, though it is still part of the sea trial. Depending on the type of ship, systems being tested may include steering, galley equipment, evaporators, hydraulics, coolers, air conditioning, generators, navigation, electrical, and main propulsion. If any of the systems are found to be faulty, repairs will be performed while still pier side and before going any further with the sea trial.
When all systems pass checks and are approved by the ship’s crew, owner, builder, and dry dock personnel, the next phase of a sea trial is general performance and seaworthiness. The ship is taken out into open water where the main propulsion systems are pushed to the limit. During this phase, the main propulsion systems and propeller shafts are checked for any unusual vibrations while at full throttle. Steering systems are also pushed to full stops at high speeds.
After all systems are checked, the ship’s crew, the dry dock crew, and owner or builder of the ship discuss the outcome of the sea trial. If there are discrepancies, or if it is determined that changes are needed, the ship goes pier side and may even go into dry dock for further repair. This process may be repeated until all parties are in agreement that the ship has successfully passed sea trial.
Checking for leaks is a common activity during a sea trial; however, this is such a necessary procedure that it is not limited to sea trials. If a boat has been in dry dock specifically for repairs to the hull, checking for leaks in the newly repaired area is a major part of a shakedown. Other areas frequently inspected for leaks during inspections include rudders, shafting, sea valves, and any place where equipment penetrates the hull.