General Oil Tanker principles

1. Oil Tankers By Siddharth ‘Sid’ Chandrasekar

8. How ?

9. Tanker Structures

12. CBT & SBT SBT Ballast water is taken on board to maintain stability, such as when a vessel is sailing empty to pick up cargo or after having unloaded cargo. Ballast water contained in segregated ballast tanks (SBT) never come into contact with either cargo oil or fuel oil CBT To have so-called dedicated clean ballast tanks (CBT) means that specific cargo tanks are dedicated to carry ballast water only.

13. Oil Discharge Monitoring & Control System

14. General Precautions on Tankers

15. General Precautions Strict smoking regulations, no smoking signs No naked lights outside accommodation Portable UHF -intrinsically safe Fixed electrical equipment - secure earth connections

16. General Precautions Portable electrical equipment Portable pumps and fans - can develop static charge Clothing – No static charge potential Deck maintenance tools (grinders, grit blasters, chippers)

17. General Precautions Main engine – Soot blowing Portable pumps and fans - can develop static charge Aluminium based primer paints interact with the rust and provide an ignition source if subsequently stuck hard by a metal object Mobile phones

18. General Precautions Cold Weather Precautions – anti freeze for deck seal & P/V breaker, fire mains drained Enclosed Space Entry Pumproom Entry Permits Hot Work Permits

19. Arrival into Port

20. Checklists Pre arrival Ship-terminal questionnaire Mooring System Checklist Ship Shore safety checklist (ISGOTT) Load / Discharge Operation Checklist Ship / Terminal Information Exchange Checklist

21. Handling of Cargo & Ballast

22. Cargo Operations Constant supervision – Ship & Shore Cargo sampling – Open & Closes systems Correct line up Incremental rate with further checks Don’t close valves against positive flow

23. Load / Discharge Plan

24. Ballast Operations Obligations to MARPOL regulations & Ballast Water Management Stability criteria, Free Surface Effect Stresses and bending moments Contamination (oil) of ballast water Minimum depth at berth and stern trim

26. The vapour return line ashore is fitted with sensors and alarms to monitor tank pressures

27. A flame arrestor will be fitted within the system on the shore side

28. A stud is located on the presentation face of the reducer flange – prevents wrongful manifold connection

30. Inert Gas Systems

32. Maintain a low, positive pressurised, inerted cargo tank atmosphere at all times

33. Removes the possibility of oxygen entering the tank

35. Types Flue Gas Generator

36. Types Inert Gas Generator

37. Inert Gas Systems IMO requirement Basic flue gas composition: O2 - content: Approx. 5% by vol. CO2 - content: Approx. 13% by vol. SO2 - content: Approx. 3000 ppm. N2 - content: Balance Inert gas composition: O2 - content: No change CO2 - content: No change SO2 - content: Less than 100 ppm N2 - content: Balance Gas outlet temperature: Max. 5°C above sea water temperature. Relative humidity: 100% Carry over of water droplets: Less than 1 g/kg dry gas.

38. Flammability Diagram AB - Hydrocarbon gas/air mixtures without inert gas C & D – LFL & UFL of HC gas in air CE & DE – Explosive limit when IG is inserted

41. Dilution

42. Displacement Displacement depends on the fact that inert gas is slightly lighter than hydrocarbon gas. The inert gas is pumped in to the top of the tank and floats on the heavier hydrocarbon gas beneath it. Continuous addition of inert gas forces the heavier hydrocarbon gas mix out of the suitable (purge) piping arrangement at the bottom of the tank. Inert gas has a very low entry velocity to enable a very stable horizontal interface to be developed between the incoming and escaping gas. In practice, some dilution inevitably takes place owing to the turbulence caused in the inert gas flow. The low pressure delivery rate of IG during displacement operations allows multiple tanks to be inerted or purged simultaneously.

43. Displacement

44. Gas Freeing In a gas freeing operation, air is delivered into the tank, where it mixes with the existing tank atmosphere and also tends to mix together any layers that may be present The resultant mixture is expelled to the outside atmosphere The process is one of continuous dilution with the air, the highest hydrocarbon concentration is vented at the beginning of gas freeing and decreases thereafter On inerted ships, purging to remove hydrocarbon vapour before gas freeing is a requirement

45. ISGOTT Publications Inert Gas Systems IGS Manual Charter Party Chief Officer’s Notes Fleet Instructions

46. P/V Valve

47. P/V Valve Protects cargo tanks that may be subject to gas/vapour pressure or vacuum outside the design parameters of the tank Prevents the passage of flame into cargo tanks Relieves excessive +/- pressure of cargo tanks during cargo operations and thermal variations The second line of defence

48. P/V Breaker

49. P/V Breaker Protects cargo tanks that may be subject to gas/vapour pressure or vacuum outside the design parameters of the tank Regular checks on water level Mix antifreeze in cold weather conditions The third line of defence

50. P/V Breaker

51. Deck Seal

52. Deck Seal Prevents Inert Gas from entering the engine room Regular checks on water level, water pump and demister pads Mix antifreeze in cold weather conditions The final line of defence

53. Deck Seal

54. Deck Seal

55. What is the 1st line of defence ? High Pressure Alarm

56. Gas Measuring Instruments

57. Gas Measuring Instruments Combustible gas meter - Measures % LFL Hydrocarbon gas meter - Measures % HC gas Oxygen analyser - Measures % O2 Specific gas detector - Measures ppm

58. Enclosed Space Entry

60. Testing equipment should have records of all maintenance work and calibration tests carried out and of the period of their validity

63. Effective ventilation & lighting will be maintained and monitored continuously while the enclosed space is occupied

64. Lifelines and harnesses are ready for immediate use at the entrance to the space

66. A responsible member of the crew is on standby outside the enclosed space in the immediate vicinity of the entrance and in direct contact with a responsible officer.

67. Communications must be established with standby man/bridge/entry personnel.

68. Personal atmosphere monitors must be worn by each tank entrant.

71. The ventilation fans shall be kept running in exhaust mode for the entire duration of validity of the permit.

72. The designated responsible person (duty officer or chief officer) shall monitor such pump room entries.

73. All entries into the pump room shall be recorded - names / ranks of persons and times of entry and exit.

74. The space must be tested for Oxygen (at least 21%), Explosive gases (HC LEL= less than 1% LEL) and Toxic vapors (Nil).

76. Ventilation fans must be started prior to switching on the pump room lighting.

77. Only approved lighting shall be used in the pump room and shall be maintained in proper condition.

78. The pump room shall be visually inspected for oil and trash (rags) regularly.

79. Pump room bilges should be kept and maintained clean and dry.

81. A multi-gas personnel detector shall be carried while being in Pump Room. Any warning from such unit indicates to evacuate immediately.

84. Remove previous cargo residues in preparation for the next cargo type (Product)

85. Prepare and clean a cargo tank for purging and gas freeing to conduct a tank inspection

87. Tank washing systems can be fixed systems (crude oil) or portable systems (products)

88. Use cargo (crude oil) or salt water to constitute the cleaning liquid, which may be heated to enhance the cleaning capabilities of the system

90. Emergency Procedures

92. Initial action to contain and overcome the incident

93. Procedures to be followed in mobilising the resources of the terminal, as required by the incident (ERP / SOPEP)

94. Evacuation procedures

95. Assembly points

96. Emergency organisation, including specific roles and responsibilities

97. Communications systems.

98. Emergency control centres.

100. Publications ISGOTT SOLAS MARPOL Guidance Manual for Tanker Structures

101. Publications SOPEP / ERP Ship Security Plan & ISPS Code Effective Mooring Ship to Ship Transfer Guide

102. Publications IGS Manual COW Manual & IMO 617E (A) Crude Oil Washing Systems Fleet Instructions & Manuals for all equipment onboard Recommendations for Oil Tanker Manifolds & Associated Equipment

103. Thank You