Section 9 Sea trials

9.1.1 Sea trials are to be of sufficient duration and carried out under normal operating conditions applicable to the intended class notation. Individual Chapters give specific requirements.

9.2.1 Sea trials are to include the demonstration of:

1. The adequacy of the starting arrangements of the main engines, auxiliary systems and emergency generators.

2. The effectiveness of the steering gear control systems.

3. Manoeuvring, to include:

   • starting;
   • normal and emergency stopping;
   • reversing;
   • governor testing;
   • safety devices, and associated indicators and alarms.

4. The redundancy arrangements for Category B craft.

5. Tooth contact markings in geared installations using a recognised technique. The marking is to be as detailed in Pt 9, Ch 2, 3.5 Meshing tests.

6. For controllable pitch propellers, the pitch setting under failure conditions.

9.2.2 Main propulsion systems are to undergo tests to demonstrate the astern response characteristics. The tests are to be carried out over at least the manoeuvring range of the propulsion system and from all control positions. A test plan is to be provided by the yard and accepted by the Surveyor. If specific operational characteristics have been defined by the manufacturer, then these are to be included in the test plan.

9.2.3 Specific requirements for shipboard trials of reciprocating internal combustion engines are provided in Pt 10, Ch 1, 11 Factory Acceptance Test and Shipboard Trials of Engines.

9.3.1 It is to be verified that the propeller performs satisfactorily under ahead and astern conditions. Where controllable pitch propellers are fitted, the free route astern trial is to be carried out with the propeller blades set in the full pitch astern condition.

9.3.2 The reversing characteristics of the propulsion plant, including the blade pitch control system of controllable pitch propellers, are to be demonstrated and recorded during trials.

9.3.3 It is to be verified that large movements of resiliently mounted machinery do not occur during start up and stop, or during normal operating conditions.

9.3.4 The installation should be tested to ensure that gas turbines cannot be continuously operated within any speed range where excessive vibration, stalling or surging may be encountered.

9.3.5 For main propulsion systems with reversing gears, controllable pitch propellers or electric propeller drive, running astern is not to lead to the overload of propulsion machinery.