Marine Tech SHIP OPERATIONS. Dr. Alok K. Verma Lean Institute - ODU

Transcription

1 SHIP OPERATIONS 1

2 Module Description and Goals This module is intended to introduce participants to basic concepts in ship loading operations and ship stability. 2

3 CONTENTS Types of Ships 5 min Ship Organization 5 min Cargo Operations 40 min Hands-on Activity 1 25 min Hands-on Activity 2 30 min Ship Motions 10 min Ship Stability 20 min Hands-on Activity 3 10 min Hands-on Activity 4 25 min Hands-on Activity 5 10 min Total 3 hrs 3

4 Drill Ship: Vessels carrying out drilling operations, equipped with drilling rig and its own propulsion machinery Types of Ships visual.merriam-webster.com/.../drill-ship.php Bulk Carrier: Single deck vessel carrying homogeneous unpacked cargoes 4

5 Container Vessel: Ship specially designed to carry standard containers Types of Ships Float-On/Float-Off: Special Vessels which may be submerged to allow the floating on or off of cargo commons.wikimedia.org/wiki/file:float_on_floa... 5

6 Barge: A flat bottomed boat used for transport of heavy goods. Types of Ships Tug Boats: Boat used to maneuver, primarily by towing or pushing other vessels. Tugboats are also used to tow barges 6

7 Find the type of ship Transport heavy goods Carry unpacked cargoes Barge Bulk carrier Carry standard containers Container Vessel Carry out drilling operations Used for towing barges Drill ship Tug Boats 7

8 SHIP ORGANIZATION The captain/master is the highest responsible officer, acting on behalf of the ships owner Captain/Master Deck Department Engine Department Steward Department 8

9 Deck Department: SHIP ORGANIZATION The department is responsible for ship s overall appearance, preservation and for safely receiving, discharging and caring of cargo during a voyage. 9

10 Deck Department Personnel Chief Mate Second Mate Third Mate Boatswain SHIP ORGANIZATION Duties Cargo Operations and Stability In charge of navigation Safety Officer Able Seamen Deck duties Ordinary seamen 10

11 Engineering Department: The department responsible for getting the ship to and from anywhere and responsible for all the equipment used throughout the ship SHIP ORGANIZATION

12 Engine Department Personnel Chief Engineer SHIP ORGANIZATION Duties Oversee Engine Department and maintenance of equipment Second Engineer Third Engineer Fourth Engineer Oiler Pump man In charge Refrigeration systems main engines In charge of boilers,feed pumps and fuel condensers Responsible for electrical, sewage treatment Operation of liquid cargo transfer system Ordinary seamen 12

13 Steward Department: The department responsible for maintaining the ship s store, providing repair parts, laundry services and also feeding the people SHIP ORGANIZATION 13

14 SHIP ORGANIZATION Steward Department Personnel Duties Chief Steward Chief Cook Steward s Assistant Preparing and serving meals and keeping inventory 14

15 SHIP ORGANIZATION 15

16 SHIP ORGANIZATION In charge of everything aboard ship Master Maintenance of ship and stowage of cargo Chief Mate In charge of machinery aboard ship Chief Engineer 16

17 Cargo Operations Stowage of Cargo Loading / Unloading Cargo 17

18 Goods carried by a ship are known as cargo Cargo Operations Stowage: Stowage is the amount of room for storing cargo on board a ship freport.wa.gov.au 18

19 Types of Cargo Container Cargo Bulk Cargo 19

20 Units of Cargo Capacity The Twenty Foot Equivalent or TEU represents the cargo capacity of a standard shipping container 20 foot long and 8 foot wide A 40-foot long container equals 2 TEU. Carrying Capacity 24 tons 20

21 Principles of Stowage The fundamental objectives of cargo stowage are: - To protect the ship - To protect the cargo - To obtain the maximum use of available cubic of ship - To provide for rapid and systematic loading and discharging 21

22 Stowage of Cargo Cargo is stowed in holds and tanks of the ships Cargo holds 22

23 Loading/Unloading Cargo Ships designed for carrying large amounts of cargo must take on ballast water for proper stability. 23

24 Loading/Unloading Cargo Ballast would be discarded when the cargo is loaded. deck Water level Water level earthsys.ag.ohio-state.edu Ballast Tanks 24

25 Loading/Unloading Cargo 2 1 At source port Cargo In - 1 Ballast water Out At destination port Cargo out - 3 Ballast Water In

26 Loading Cargo There are three basic methods of arranging items in cargo hold: 26

27 1. Horizontally: When a single item or class of items is to be stored in a layer that fills from side to side and front to rear. Loading Cargo 27

28 2. Vertically: Loading Cargo Items are stored in columns that go from top of the hold on down so that several types of items are available during any stage of emptying hold 28

29 Loading Cargo 3. In Blocks: Assortments of various types of items are made up and loaded together. 29

30 HANDS ON ACTIVITY - 1 Loading Cargo 30

31 Stowage of Cargo Volume Given a certain amount of cargo what is the amount of space that will be consumed in stowing it? 31

32 Stowage of Cargo Weight Given certain volume of space what is the number of tons, units or pieces that will go into the space? 32

33 Stowage of Cargo A value that is used to answer the above two questions: Stowage Factor 33

34 Stowage of Cargo Stowage Factor: The stowage factor is defined as the number of cubic feet required to stow 1 ton of a given cargo. f = 2,240/D cu ft/ton = 2,240 x V/W cu ft/ton 34

35 Stowage of Cargo Where, f = Stowage factor D = Density of the commodity in pounds per cubic foot 2,240 = The number of pounds in 1 long ton V = Volume of the container W = Weight of container in pounds 35

36 36

37 Stowage of Cargo A cargo consisting of cases weighing 400 pounds and measuring 2.5 feet x 1 feet x 1 feet to be stowed. Find stowage factor(f)? f = 2240 *V/W V = 2.5 x 1 x 1= 2.5 cu ft W = 400 pounds f = 2240 x 2.5/400 f = 14 cu ft/ton 37

38 Broken Stowage: Stowage of Cargo The cargo space which is unavoidably lost when stowing cargo due to the type and nature of cargo loaded. Broken Stowage 38

39 Stowage of Cargo V = Volume of cargo hold v = Volume of cargo stowed in V Broken Stowage The percentage of broken stowage =L= (V-v)/V *100 39

40 Stowage of Cargo Given a certain volume of space(v), a cargo with a stowage factor(f) and estimated broken stowage percentage (L) the number of tons(t) of cargo that will fit into space is T = (V *(1-L)) / f 40

41 41

42 Stowage of Cargo The volume of the cargo hold is 60,000 cu ft. Estimated broken stowage is 10 percent and stowage factor is 56. Find the number of tons(t) that can be stowed in the hold? T = (V *(1-L)) / f T = 60000*0.9/56 T = 964 tons 42

43 BREAK 5 minutes 43

44 Water Line Cargo Loading Draft: The draft of the ship s hull is the vertical distance between the waterline and the bottom of the hull 44

45 Cargo Loading A ship can be fully loaded in three ways: 1. FULL IN WEIGHT: It can be full in weight when it is at its maximum draft Draft line Water line Max draft 45

46 Cargo Loading 2. FULL IN SPACE: It can be full in space when the hold is filled up to the hatch covers 46

47 Cargo Loading 3. FULL AND DOWN: It is full in weight as well as in space Max draft 47

48 HANDS ON ACTIVITY - 2 Cargo Loading 48

49 Cargo Loading Load the ship to obtain a Full and Down condition and calculate Broken Stowage. 49

50 Cargo Loading Step 1: Calculate the volume of the cargo hold (V) : Measure the height (h),width (w) and depth (d). 50

51 Cargo Loading Step 2: Load the ship till the ship is at its maximum draft. Water line 51

52 Cargo Loading Max draft Water line 52

53 Cargo Loading Step 3: Calculate total volume occupied by the cargo(v) : Step 4: Calculate percentage of broken stowage : L= (V-v) / V *100 L : The percentage of broken stowage V : Volume of cargo hold v : Volume of cargo stowed in V 53

54 Types of Cranes Used: Cargo Loading Container being loaded on a ship Gantry cranes are used to move containers to or from the ship. 54

55 Cargo Loading Another type of Gantry Crane 55

56 Cargo Loading Bulk handling crane used for lifting bulk cargoes 56

57 Cargo Loading Deck cranes are located on ships and boats and used for cargo loading and unloading where shore unloading facilities are not available 57

58 Cargo Loading - Video 58

59 Ship Motions Pitch: Vessel rotates about the transverse (side-to-side) axis. Roll: Vessel rotates about longitudinal (front/back) axis. 59

60 Ship Motions Yaw: Vessel rotates about vertical (up/down) axis. Surge: Linear longitudinal (front/back) motion. 60

61 Ship Motions Heave : Linear vertical (up/down) motion. Sway: Linear lateral (side-toside) motion. 61

62 Find the type of Motion Linear longitudinal motion Motion along longitudinal axis Motion along transverse axis Linear vertical motion. Surge Roll Pitch Heave 62

63 Ship Stability The stability of a vessel refers to its ability to stay upright in the water. The main consideration is the correct distribution of cargo weight. celebrating200years.noaa.gov/.../cargo-ship.html 63

64 Ship Stability If too much weight is in the upper decks of ship, the ship will have small amount of stability and be in a condition known as tender. If too much weight is concentrated on lower holds the ship will have excess of stability and be in a condition known as stiff. 64

65 Ship Stability Hogging too much weight at the ends Fore Aft Sagging too much weight amidships Fore Aft 65

66 Ship Stability While stowing the cargo, the only necessity is to ensure that the weight is equal on both sides of the ship s centerline 66

67 Ship Stability The initial stability of a ship refers to the relationship between three important points on it. The Center of Gravity (G) The Center of Buoyancy (B) The Metacenter (M) M G B Cross sectional view of ship 67

68 Center of Gravity The center of gravity (G) is the point at which the whole weight of the vessel can be said to act vertically downward. G 68

69 Center of Gravity As a general rule a lower center of gravity means a more stable vessel 69

70 Center of Buoyancy A body submerged wholly or partially in a fluid is buoyed up by a force equal to the weight of the fluid displaced. Center of buoyancy(b) is the center of gravity of the volume of water the hull displaces. 70

71 HANDS ON ACTIVITY - 3 Find Center of Gravity and Center of Buoyancy 71

72 Line through B When ship is in equilibrium M G B M G Metacenter B Line through B When ship is inclined Metacenter is the intersection between the line through the center of buoyancy of a hull in equilibrium, the line through the center of buoyancy when the hull is inclined slightly 72

73 GM Metacentric Height GM Metacentric Height M G B G M B (GM) is the distance between the metacenter and the center of gravity of the vessel. 73

74 Adding or shifting weights vertically causes center of gravity to move in the same direction. Metacentric Height GM If center of gravity is too high the ship becomes unstable. 74

75 Metacentric Height GM If Meta center(m) is above the Center of Gravity(CG) the ship is stable. Will tend to upright itself when tilted by a wave. G M 75

76 Metacentric Height GM If Meta center(m) is below the Center of Gravity(CG) the ship is unstable. Will not upright itself if tilted by a wave. M G 76

77 HANDS ON ACTIVITY - 4 Metacentric Height 77

78 Metacentric Height GM Model used for metacentric height calculation The weights (w) are shifted from center through a distance of d cm 78

79 Shift in Center of Gravity = GG1= (w*d)/w Metacentric Height GM G = Original center of gravity G1= New center of gravity d = distance moved in cm W = weight of ship w = weight of washers d w 79

80 Metacentric Height GM AB Metacentric Height (GM) = GG1* BC/AB Plumb Line Plumb Weight BC 80

81 Free Surface Effect Free surface effect is one of the several mechanisms where a ship can become unstable and roll-over (capsize). 81

82 Free Surface Effect It refers to the tendency of liquids and of small objects which can act as liquid and can shift inside cargo holds. 82

83 When a vessel with full tank heels over, the contents of the tank do not shift. Free Surface Effect The tank's centre of gravity does not change, so it does not affect the vessel's stability 83

84 When a vessel with partially filled tank heels over, the contents of the tank will shift. Free Surface Effect The centre of gravity moves over to the side, making the vessel less stable. 84

85 Free Surface Effect This effect is similar to that caused by adding weights on deck raising the vessel s CG which causes a decrease in GM and thereby it s stability 85

86 Free Surface Effect How to avoid free surface effect? Try to have as few partially filled tanks and compartments as possible. By dividing a tank into two equal parts with a baffle, the free surface effect is greatly reduced. 86

87 HANDS ON ACTIVITY - 5 Free Surface Effect 87

88 Review of Topics Types of ships based on their application Different departments in a ship and its organization Cargo loading and unloading operations Six types of ship motions in response to the sea Stability of a ship Calculation of Metacentric height Free surface effect 88

89 For more information on this module Please contact: Dr. Alok K. Verma, P.E., CmfgE Ray Ferrari Professor Director-Lean Institute Old Dominion University. Phone (757) Fax (757)