Before a new vessel can be officially delivered, it must undergo a comprehensive on-water performance test – this is the sea trial. For Jiangsu Haizhongzhou Shipping Industry Co., Ltd., a sea trial is not simply "taking the ship out for a spin," but rather a rigorous technical inspection process that verifies whether all aspects of the vessel's performance meet contractual and regulatory requirements.
The preparation phase of a sea trial is often underestimated. The formal sea trial program must be approved by both the owner and the classification society, clearly defining the methods, operating conditions, acceptance criteria, and division of responsibilities for each test. Under what water depth conditions should speed trials be conducted? How should the rudder angle sequence for turning circle tests be set? How long should the unmanned engine room test last? – every detail must be confirmed item by item. Simultaneously, the shipyard must complete all outstanding items from the quay-side mooring trial phase to ensure the vessel's condition is ready for sea.
The test content on the day of the sea trial typically covers five major areas: speed measurement, maneuverability testing, propulsion system validation, anchoring equipment testing, and navigation/communication equipment commissioning. Speed measurement requires running multiple load conditions in both directions within a defined speed trial area, precisely recording the track and time using DGPS, and ultimately calculating the actual speed under no-wind, no-current conditions. Maneuverability testing includes turning circle tests, zig-zag (Z) maneuvering tests, and crash stop tests, comprehensively verifying the vessel's steering response, rudder effectiveness, and braking capability.
Propulsion system validation is equally stringent. The main engine must run stably at various power points, with key parameters such as exhaust temperature, firing pressure, and fuel consumption recorded. Load increase and load rejection tests are completed to confirm that the governor's response speed meets specifications. The unmanned engine room test verifies that, with the engine room unattended, all alarm and safety protection systems can automatically respond and record the moment a fault occurs.
Significant changes have also emerged in recent years in the collection and analysis of sea trial data. Whereas data recording once relied on manual meter reading, large volumes of parameters are now automatically collected via sensors to generate sea trial reports. Upon returning to port, the data is compared with theoretical design values, and deviation analysis results become the objective basis for determining whether the vessel meets performance standards. Once the sea trial is passed and the owner signs the delivery documents, the vessel – which represents months of effort by thousands of people – truly qualifies to head out to sea.
