1. The Manoeuvrability of Very Large and Ultra Large Container Ship
IMPA 2014 Conference
Technical Presentation
April 2014, Panama
The Manoeuvrability of Very Large and Ultra Large Container Ship
Captain S. M. Goag
KOREA MARITIME PILOT’S ASSOCIATION

2. The enlargement of container ship
1970's : 2,100 TEU
1980's : 4,400 TEU
1990's : 6,400 TEU
2000's : 14,800 TEU
2013 : 18,200 TEU 1

3. Course stability Turning ability
Ship manoeuvrability
Course stability
Turning ability 2

4. The Standards applied to ships constructed on or after 1 January 2004
IMO standards for ship manoeuvrability
History
4 Nov Interim Standards for ship menoeuvrability - IMO Resolution A.751(18)
4 Dec The Standards for ship manoeuvrability - Resolution MSC.137(76)
The Standards applied to ships constructed on or after 1 January 2004 3 3

5. Contents of Standards
Condition .1 deep, unrestricted water; .2 calm environment; .3 full load(summer load line draught), even keel condition; and .4 steady approach at the test speed. 4

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

7. Initial turning ability
With the application of 10° rudder angle to port/starboard, the ship should not have travelled more than 2.5 ship lengths by the time the heading has changed by 10° from the original heading. 6

8. Yaw-checking and course-keeping abilities
.1 the first overshoot angle in the 10°/10° zig-zag test should not exceed: .1 10° if L/V is less than 10 s; .2 20° if L/V is 30 s or more; and .3 (5 + 1/2(L/V)) degrees if L/V is 10 s or more, but less than 30 s where L : m, V : m/sec 7

9. Yaw-checking and course-keeping abilities
.2 the second overshoot angle in the 10°/10° zig-zag test should not exceed: .1 25°, if L/V is less than 10 s; .2 40°, if L/V is 30 s or more; and .3 ( (L/V))°, if L/V is 10 s or more, but less than 30 s. .3 The first overshoot angle in the 20°/20° zig-zag test should not exceed 25°. 8

10. 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 practicable, but should in no case exceed 20 ship lengths. 9

11. Size categories of container ship10

12. Particulars of Container ship11

13. Turning circles of container ships12

14. Turning circles of container ships13

15. Comparison of turning circles VLCS and VLCC14

16. Comparison of turning circles VLCS and VLCC15

17. Initial turning ability16

18. Initial turning ability17

19. Yaw checking and course keeping ability (overshoot angle)18

20. Yaw checking and course keeping ability (overshoot angle)19

21. Pullout test 20

22. Pullout test 21

23. Stopping ability 22

24. Stopping ability 23

25. Stopping ability 24

26. Stopping ability 25

27. Stopping inertia 26

28. Stopping inertia 27

29. Stopping inertia 28

30. The block co-efficient of container ships ranges from 0.64 to 0.71.
Conclusion
Hull shape
The block co-efficient of container ships
ranges from 0.64 to 0.71.
Though container ships are getting bigger,
hull shape is little changed.
Even the ULCV is much slimmer than VLCC
in terms of length/breadth ratio. 29

31. The turning ability of container ships, large
Conclusion
Turning ability
The turning ability of container ships, large
or small, of which the length is larger
compared with their breadth is not better
than that of VLCC.
The advances of container ships range
from 3.1 to 3.4 times of their length while
VLCCs‘range from 2.5 to 2.8. 30

32. Conclusion
Especially the turning circle of ballasted ULCV is almost 2 times as large as that of loaded VLCC. In case of VLCC, there is not so much difference in turning circle between ballast and loaded condition but in case of ULCV, the turning circle of trimmed ballast condition is much larger than that of fully loaded condition(abt times in tactical diameter). 31

33. Initial turning ability It is amazing that there is not so much
Conclusion
Initial turning ability
It is amazing that there is not so much
difference in initial turning ability between
Ballasted container ships and fully loaded
VLCCs. They range from 1.5 to 1.7 times of
Their length.
It can be thought that the speed difference
between container ship and VLCC, 32

34. Conclusion
poor turning ability of container ship and poor following response for rudder of VLCC caused these results. But the elapsed time the heading has changed by 10° from the original heading of VLCC is much longer than that of container ship which means the following ability for the rudder of VLCC is poor. 33

35. In terms of course stability, VLCC can not
Conclusion
Course stability
In terms of course stability, VLCC can not
be compared with container ship.
The 1st & 2nd overshoot angles of container
ships do not exceed 5° at 10°/10°
zig-zag test and at even 20°/20° zig-zag
test the 1st overshoot angles donot
exceed 10°. 34

36. Conclusion
318K VLCCs' are almost the criteria of IMO standards. At the pullout test, the residual rate of turn of container ship is near zero for both port and stb'd turns, which mean the ship is stable but VLCC's is 5°, which means she is unstable. 35

37. Stopping ability and inertia As the data for Full loaded condition of
Conclusion
Stopping ability and inertia
As the data for Full loaded condition of
container ship is unavailable and the
engine power is not same, direct
comparison is meaningless.
In any case, the track reach donot exceed
IMO Standards, that is 15 times of ship's
length. 36

38. Conclusion
It is heard that the track reach at crash stop astern test during sea trial of new ships very rarely exceed 15 ship's length. The result of crash astern and stopping inertia can be used for guidance. 37

39. Conclusion
- Though the data is unsufficient for making a conclusion, it can be carefully thought that the manoeuvrabing characteristics remains unchanged though ships are getting bigger unless the hull shpae is not changed. 38

40. - THANK YOU -
KOREA MARITIME PILOT’S ASSOCIATION