1. Hull Damage and List in Stability
Lesson 4.6
Hull Damage and List in Stability B B1 M G G2

2. "IF PERSONNEL WAIT UNTIL CATASTROPHE IS ACTUALLY IMPENDING BEFORE STARTING TO LEARN THEIR SHIP BY MEANS OF THE FOREGOING PREPARATORY MEASURES, THE SHIP AND ITS COMPANY MAY BE LOST."
NSTM 079 VOL I

3. CLASS TOPICS
1. Causes of Loss 2. Movie (USS Wilkes Barre) 3. Metacentric Height 4. List in Stability 5. Floodable Length 6. Dynamic Stability 7. Decision Factors

4. FOLLOWING DAMAGE
War experience shows two situations exist following the infliction of damage:
DAMAGE IS SO EXTENSIVE THAT THE SHIP NEVER STOPS LISTING, TRIMMING, OR SETTLING AND GOES DOWN WITHIN MINUTES.
THE SHIP STOPS HEELING, CHANGING TRIM, AND SETTLING SHORTLY AFTER INITIAL DAMAGE OR
Experience has shown that the loss of ships which last several hours and then sink is directly traceable to PROGRESSIVE FLOODING

5. SHIP SINKINGS • BODILY SINKAGE • CAPSIZING • PLUNGING • BREAKING UP
WATER LEVEL G
• BODILY SINKAGE
LOSS OF BUOYANCY B
• CAPSIZING
LOSS OF TRANSVERSE STABILITY
• PLUNGING
LOSS OF LONGITUDINAL STABILITY
• BREAKING UP
LOSS OF SHIP'S GIRDER

6. CLASS TOPICS
1. Causes of Loss 2. Movie (USS Wilkes Barre) 3. Metacentric Height 4. List in Stability 5. Floodable Length 6. Dynamic Stability 7. Decision Factors

7. METACENTRIC HEIGHT
RIGHTING ARM (GZ) IS PROPORTIONAL TO METACENTRIC HEIGHT (GM)
A SHIP WITH:
LARGE GM IS STIFF AND RESISTS ROLLS
SMALL GM IS TENDER AND ROLLS EASILY AND SLOWLY
VERY SMALL GM IS APT TO HANG AT THE END OF EACH ROLL BEFORE STARTING UPRIGHT
SLIGHTLY NEGATIVE GM IS APT TO LOLL (STAYING HEELED AT ANGLE OF INCLINATION WHERE RIGHTING AND UPSETTING FORCES ARE EQUAL) AND FLOP FROM SIDE TO SIDE
NEGATIVE GM WILL CAPSIZE WHEN INCLINED

8. SURVIVABILITY OF THE SHIP
IF NO LIST IS PRESENT:
IF GM HAS BEEN SIGNIFICANTLY REDUCED THE SHIP MAY BE IN DANGER OF CAPSIZING EVEN THOUGH THERE IS NO LIST A SMALL HEELING MOMENT WILL PRODUCE A LARGE INCLINATION.

9. ROLLING ANGLE WHEN RELATED TO WAVE PERIOD vs SHIP PERIOD
GM =
( )
.44 x B T 2
T =
.44 x B GM

10. CLASS TOPICS
1. Causes of Loss 2. Movie (USS Wilkes Barre) 3. Metacentric Height 4. List in Stability 5. Floodable Length 6. Dynamic Stability 7. Decision Factors

11. G MOVED OFF CENTERLINE (99%) -GM (1%) COMBINATION OF -GM AND G OFF CL
3 BASIC CONDITIONS WHICH MAY CAUSE THE SHIP TO TAKE ON A PERMANENT LIST:
G MOVED OFF CENTERLINE (99%)
-GM (1%)
COMBINATION OF -GM AND G OFF CL G G2 M

12. LIST DUE TO G BEING SHIFTED OFF-CENTERLINEM G G2 G

13. LIST DUE TO G BEING SHIFTED OFF-CENTERLINEM G G2 B1 B B1 M G G2 B M G G2 B1 B M G B1 G2 B M G B1 G2 B M G B1 G2 B M G B1 G2

14. G OFF CENTERLINE 5 4 3 2 1 -1 RIGHTING ARMS (FT) ANGLE OF LIST
ANGLE OF LIST
MAX RANGE OF STABILTY -1 10 20 30 40 50 60 70 80 90
ANGLE OF INCLINATION - DEGREES

15. CAUSES CORRECTIVE MEASURES
1. Unequal distribution of weight on either side of center line due to loading. 2. Shift of weight transversely. 3. Addition or removal of weight unsymmetrically about center line.
CORRECTIVE MEASURES
1. Determine cause of list 2. Shift weigth transversley to high side 3. Add weight to high side or remove weight from low side

16. G MOVED OFF CENTERLINE (99%) -GM (1%) COMBINATION OF -GM AND G OFF CL
3 BASIC CONDITIONS WHICH MAY CAUSE THE SHIP TO TAKE ON A PERMANENT LIST:
G MOVED OFF CENTERLINE (99%)
-GM (1%)
COMBINATION OF -GM AND G OFF CL G G2 M

17. LIST DUE TO A SLIGHTLY NEGATIVE GMB

18. LIST DUE TO A SLIGHTLY NEGATIVE GMB B1

19. LIST DUE TO A SLIGHTLY NEGATIVE GMB B1

20. NEGATIVE GM 5 4 3 2 1 -1 RIGHTING ARMS (FT) ANGLE OF LIST
MAX RANGE OF STABILITY -1 10 20 30 40 50 60 70 80 90
ANGLE OF INCLINATION - DEGREES

21. CAUSES
1. Removal of low weights 2. Addition of high weights (ice) 3. Moving weights upward 4. Free Surface Effect 5. Free Communication Effect

22. CORRECTIVE MEASURES
1. Eliminate Free Surface and Free Communication Effects 2. Add low weight symmetrically 3. Remove high weight symmetrically 4. Move weight down symmetrically

23. G MOVED OFF CENTERLINE (99%) -GM (1%) COMBINATION OF -GM AND G OFF CL
3 BASIC CONDITIONS WHICH MAY CAUSE THE SHIP TO TAKE ON A PERMANENT LIST:
G MOVED OFF CENTERLINE (99%)
-GM (1%)
COMBINATION OF -GM AND G OFF CL G G2 M

24. NEGATIVE GM WITH G OFF CL5
NEGATIVE GM WITH G OFF CL 4 3
RIGHTING ARMS (FT) 2
MAX RANGE OF STABILITY 1
ANGLE OF LIST -1 10 20 30 40 50 60 70 80 90
ANGLE OF INCLINATION - DEGREES

25. CAUSES CORRECTIVE MEASURES
1. Combination of the -GM and G off centerline.
CORRECTIVE MEASURES
1. Correct -GM first

26. THE WAY TO CORRECT A LIST THAT IS DUE TO THE CONDITION OF -GM WITH OFF CENTER WEIGHT IS:
1. RID THE -GM 2. ADD WT LOW SYMMETRICALLY 3. REMOVE THE OFF CENTER WT.

27. CLASS TOPICS
1. Causes of Loss 2. Movie (USS Wilkes Barre) 3. Metacentric Height 4. List in Stability 5. Floodable Length 6. Dynamic Stability 7. Decision Factors

28. FLOODABLE LENGTH
A LIST OF FLOODABLE COMPARTMENT GROUPS IS OFTEN FOUND. FOR EXAMPLE, FOR A FFG-7:
STEM - FRAME 100 FRAMES FRAMES FRAMES FRAMES FRAMES FRAMES FRAMES FRAMES STERN
GENERAL RULE: SHIP'S LBP > 300 FT ä 15% LBP < 300 FT ä 2 SPACES <100 FT ä 1 SPACE

29. FLOODABLE LENGTH DAMAGE
Second Deck (DC Dk)
First Platform
Main Deck
Second Platf
212
328

30. FLOODABLE LENGTH DAMAGE

31. FLOODABLE LENGTH DAMAGE

32. FLOODABLE LENGTH DAMAGE

33. FLOODABLE LENGTH DAMAGE

34. FLOODABLE LENGTH
A LIST OF FLOODABLE COMPARTMENT GROUPS IS OFTEN FOUND. FOR EXAMPLE, FOR A FFG-7:
STEM - FRAME 100 FRAMES FRAMES FRAMES FRAMES FRAMES FRAMES FRAMES FRAMES STERN
GENERAL RULE: SHIP'S LBP > 300 FT ä 15% LBP < 300 FT ä 2 SPACES <100 FT ä 1 SPACE

35. CLASS TOPICS
1. Causes of Loss 2. Movie (USS Wilkes Barre) 3. Metacentric Height 4. List in Stability 5. Floodable Length 6. Dynamic Stability 7. Decision Factors

36. DYNAMIC STABILITY & THE STABILITY CURVE
RIGHTING ENERGY
RM = GZ x Wf
RIGHTING MOMENTS (FT-T)
RIGHTING ARMS (FT)
ANGLE OF HEEL (DEG)
HEELING ENERGY
RIGHTING MOMENTS (FT-T)
ANGLE OF HEEL (DEG)

37. RESERVE DYNAMIC STABILITY
HEELING EFFECTS OF BEAM WINDS
FULL LOAD A
AREA A = AREA B B
ANGLE OF MAX ROLL
RESERVE DYNAMIC STABILITY
RIGHTING ARMS (FT)
100 KT
ANGLE OF SEMI-PERMANENT HEEL
ANGLE OF HEEL (DEG)

38. HEELING EFFECTS OF BEAM WINDS
FULL LOAD
RIGHTING ARMS (FT)
100 KT
DAMAGED
ANGLE OF HEEL (DEG)

39. HEELING EFFECTS OF BEAM WINDS
RIGHTING ARMS (FT)
ANGLE OF HEEL (DEG)
FULL LOAD
100 KT
60 KT
HEELING EFFECTS OF BEAM WINDS

40. DESIGNED RESISTANCE TO DAMAGE
STABILITY DESIGNED TO RESIST SPECIFIC CONDITIONS
• HEELING EFFECT OF BEAM WINDS AND SEAS • SURVIVE FLOODING FOR SPECIFIC OPENINGS OF THE HULL • LAW OF 15's
– BWS – HEAVY OBJECTS OVER THE SIDE – LIST AFTER DAMAGE – FULL SPEED, FULL RUDDER TURN – 15% LBP

41. LIMITATIONS
• LIMITING DRAFT • NO ABNORMAL WEIGHTS TOPSIDE (FFG-7's HAVE ICING DIAGRAMS) • LLI • W/T INTEGRITY

42. SURVIVABILITY OF THE SHIP
If the ship lists to the Danger Angle (1/2 the angle where the maximum righting arm occurs) within minutes after damage it is probable that it will capsize.

43. SURVIVABILITY OF THE SHIP
THE DANGER ANGLE IS APPROX. THE ANGLE WHERE THE WEATHER DECK IS ALMOST CONTINUOUSLY AWASH.

44. SURVIVABILITY OF THE SHIP
If the ship lists to the Angle of Maximum Righting Arm the ship will capsize.

45. LIST TO ANGLE OF MAXIMUM RIGHTING ARM1 2 3 -1 X

46. CLASS TOPICS
1. Causes of Loss 2. Movie (USS Wilkes Barre) 3. Metacentric Height 4. List in Stability 5. Floodable Length 6. Dynamic Stability 7. Decision Factors

47. SURVIVABILITY FACTORS:
FIRST DECISION
SURVIVABILITY FACTORS:
Ability to control and extinguish fires, and control flooding Ability to reach a safe haven Ability to float and stay upright Ability to stay in action and repel attack. (Department Heads)

48. SECOND DECISION STEP ONE - STEP TWO - ESTABLISH FLOODING BOUNDARIES
DEWATER ANY SPACE COLORED PINK ON THE FLOODING EFFECTS DIAGRAM.

49. STEP THREE -
SIZE UP THE SITUATION TO DETERMINE WHETHER STABILITY IS CRITICAL BEFORE ANY FURTHER ACTION IS TAKEN.

50. CRITICAL STABILITY 1. The ship has a negative GM
2. The ship is listing to the danger angle (1/2 angle of max GZ)
3. The extent of flooding exceeds floodable length.
4. High winds or rough seas combined with flooding

51. STEP FOUR -
ELIMINATE OR REDUCE LIST

52. EXCESSIVE TRIM (> 1% LBP)
ACTIONS
SHIFT CENTER OF GRAVITY TOWARDS "HIGH" END.