Shiphandling with Tugs - diagrams

Question 1

Answer 1

FIg. 8-1. Ship hull pressure zones

Question 2

Answer 2

Fig. 8-2. Conventional tug coming alongside a ship’s quarter

Answer 3

Fig. 8-3. Tractor, ASD tugs coming alongside stern quarter

Answer 4

Fig. 8-4. Pressure zones, different bow shapes

Question 5

Answer 5

Fig 8-5. ASD passing a towline to the ship’s bow

Question 6

Answer 6

Fig. 8-6. Approaching aft of the ship’s bow

Question 7

Answer 7

Fig. 8-7. Stemming situations

Question 8

Answer 8

Fig. 8-8. Comparative advantage of tractor/ASD vs. conventional tug in stemming situations.

Question 9

Answer 9

Fig. 8-9. Passing a line to ship’s stern.
A: Tug approaching stern
B: Holding in a safe position
C: Ready to work

Question 10

Answer 10

Fig. 8-10. Transitioning to push/pull.

Question 11

Answer 11

Fig. 9-1. Balance of towline force

Question 12

Answer 12

Fig. 9-2. Center of Hydrodynamic Pressure (CHP).
D: Drag Component
L: Lift component
F: Resultant Hydrodynamic force

Question 13

Answer 13

Fig. 9-3. Conventional tug maneuvering on towline.
CHP to TP = Turning Lever (TL), TP to PP = Maneuvering Lever (ML)

Answer 14

Fig. 9-4. Effect of snapping the tow

Question 15

Answer 15

Fig. 9-5. Tractor (ASD) tug maneuvering on towline.

Question 16

Answer 16

Fig. 9-6. Tractor/ASD Reverse tractor comparison. Note longer maneuvering lever of ASD reverse tractor

Question 17

Answer 17

Fig. 9-7. Two methods of making a conventional tug rest alongside.

Question 18

Answer 18

Fig. 9-8. Force components of a tug’s push

Question 19

Answer 19

Fig. 9-9. Maneuvering and turning levers of a conventional tug pushing.

Question 20

Answer 20

Fig. 9-10. Conventional tug pushing on ship

Question 21

Answer 21

Fig. 9-11. Tractor and ASD tugs pushing on ship

Question 22

Answer 22

Fig. 9-12. Conventional and ASD tugs backing on a line

Question 23

Answer 23

Fig. 9-13. Conventional and tractor tugs secured for breasted towing alongside a ship

Question 24

Answer 24

Fig. 9-14. Effect of tug’s angle in breasted towing

Question 25

Answer 25

Fig. 9-15. Conventional tug on a towline as the trailing tug

Question 26

Answer 26

Fig. 9-16. Conventional tug on split headlines as the trailing rug

Question 27

Answer 27

Fig. 9-17. Wrapped headline on conventional tug

Question 28

Answer 28

Fig. 9-18. Direct, in-direct, powered in-direct towing modes

Question 29

Answer 29

Fig. 9-19. Powered indirect towline forces.

Question 30

Answer 30

Fig. 9-20. ASD jackknife maneuver

Question 31

Answer 31

Fig. 9-21. Line loads on a short towline

Question 32

Answer 32

Fig. 9-22. cont. Line loads on a short towline