Manoeuvring criteria

The manoeuvrability of the conventional ship at full load is considered satisfactory if the following criteria are complied with:

1. Turning ability  – the advance should not exceed 4.5 ship lengths (L) and the tactical diameter should not exceed 5L in the turning circle manoeuvre.

2. Initial turning ability  – With the application of 10° rudder angle to port/starboard, the ship should not have travelled more than 2.5L by the time the heading has changed by 10° from the original heading.

3. Yaw-checking and course-keeping abilities

 The value of the first overshoot angle in the 10°/10° zig-zag test should not exceed:

- 10° if L/V is less than 10s,

- 20° if L/V is 30s or more,

- (5+1/2(L/V) degrees if L/V is 10s or more, but less than 30s, where L and V are expressed in m and m/s, respectively.

 The value of the second overshoot in the 10°/10° zig-zag test should not exceed:

- 25° if L/V is less than 10s,

- 40° if L/V is 30s or more,

- (17.5+0.75(L/V) degrees if L/V is 10s or more, but less than 30s.

The value of the first overshoot angle in the 20°/20° zig-zag test should not exceed 25°.

4. Stopping ability  – The track reach in the full astern stopping test should not exceed 15 ship lengths. However, this value may be modified by the Administration where ships of large displacement make this criterion impracticable, but should in no case exceed 20 ship lengths.

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