1. Lesson 4.3
Loose Water G B M B1 G2 Z Z2 G3 Z3

2. CLASS TOPICS
1. Free Surface Effect 2. Example 3. Free Communication 4. Example

3. FREE SURFACE EFFECT Z G B M B1 G B M B1 G B M B1 G B M B1 G B M B1 G B

4. FREE SURFACE EFFECT G B M B1 G2 G B M B1 G2 G B M B1 G2 B1 G2 G B M GZ3 Z Z2

5. B M B1 G G3

6. B M B1 G G3
GG3

7. FREE SURFACE EFFECT B3 x L GG3 = 12 x 35 x Wf
B = BREADTH OF COMPT L = LENGTH OF COMPT Wf = SHIP'S DISPLACEMENT
FREE SURFACE EFFECT =
MOMENT OF INERTIA =
SHIP'S DISPLACED VOLUME

8. POCKETING - SHALLOW

9. POCKETING
(NO POCKETING EXISTS)

10. POCKETING - ALMOST FULL

11. SURFACE PERMEABILITY

12. SLUICE VALVES - Closed

13. SLUICE VALVES - Open

14. FREE SURFACE EFFECT
• Greater with increased length and width of the compartment • Increases as draft decreases (de-ballasting) • Independent of the depth of the liquid • Can be reduced by pocketing

15. CLASS TOPICS
1. Free Surface Effect 2. Example 3. Free Communication 4. Example

16. Wo = 3500 Tons
25 FT
FWD
AFT
PORT
STBD
4 FT
30 FT
FSE?

17. CLASS TOPICS
1. Free Surface Effect 2. Example 3. Free Communication 4. Example

18. FREE COMMUNICATION EFFECT FREE COMMUNICATION EFFECT G B M
FREE COMMUNICATION EFFECT G B M G B M G2 G4 B1
FREE COMMUNICATION EFFECT G B M G2 G4 B1
FREE COMMUNICATION EFFECT G B M G2 G4 B1
FREE COMMUNICATION EFFECT G B M G2 G4 B1
FREE COMMUNICATION EFFECT G B M G2 G4 B1
FREE COMMUNICATION EFFECT G B M G2 G4 B1
FREE COMMUNICATION EFFECT G B M G2 G4 B1
FREE COMMUNICATION EFFECT G5 Z5
G3G5 G3 Z4

19. FREE COMMUNICATION EFFECT
G3G5 =
B x L x Y2
35 x Wf
B = BREADTH OF COMPT L = LENGTH OF COMPT Y = DIST FM SHIP C/L TO COMPT COG. Wf = SHIP'S DISPLACEMENT
FREE COMMUNICATION EFFECT

20. FREE COMMUNICATION EFFECT
COMPARTMENT OPEN TO THE SEA
COMPARTMENT PARTIALLY FLOODED
COMPARTMENT OFF-CENTERLINE OR ASYMMETRICAL ABOUT THE CENTERLINE

22. COMPARTMENT OPEN TO SEA COMPARTMENT PARTIALLY FLOODED
Y = O NO F.C.E. .

23. CLASS TOPICS
1. Free Surface Effect 2. Example 3. Free Communication 4. Example