Tankers

1. Tankers

2. The new design provides safe, reliable & economical transport of chemical & petroleum products. • It incorporates propulsive redundancy(the ability of the system to remain in operation)from the simplest single screw propulsion (jednovijačni pogon), to the most comprehensive systems with two totally independent propulsion lines including twin screw ( dvovijačni) or twin propulsion.

3. Basic characteristics of a crude oil tanker

4. Chemical tanker, Product tanker, Oil tanker 1. Balanced rudder ( balasno kormilo) with conventional propeller2. Auxiliary unit (pomoćni uređaj) 3. Lifeboat in gravity davits (grav. soha) 4. Hydraulic prime mover (pokr. snaga) 5. Cargo control room6. Tank heating / tankwash room7. Cofferdam, empty space between two tanks8. Vent pipes with pressure-vacuum valves (ventil) 9. Hydraulic high pressure oil lines for anchor and mooring gear,10. Crane11. Manifold (gl. ventil za ukrcaj/iskrcaj nafte) 12. Wing tank in double hull (bočni tank u dvodnu) 13. Double bottom tank14. Tanktop (pokrov dvodna) 15. Longitudinal vertically corrugated bulkhead16. Transverse horizontally corrugated bulkhead17. Cargo pump 18. Catwalk (prijelazni most kod tankera) 19. Railing20. Deck longitudinals(uzdužno ojačanja) 21. Deck transverses(okvirna sponja) 22. Cargo heater23. Forecastle deck with anchor-and mooring gear24. Bow thruster(pramčani propeler / vijak) 25. Bulbous bow(bulbasti pramac)

5. Tankers are designed to carry liquid cargoes (not just oil) Oil tankers come in two basic types: • the crude carrier, which carries crude oil, and • the clean products tanker, which carries the refined products, such as petrol, gasoline, aviation fuel, kerosene and paraffin. Tankers range in all sizes: • the small bunkering tanker (used for refuelling larger vessels) of 1000 D W T tons, • the VLCC (Very Large Crude Carrier) of between 2-300,000 D W T , and • the ULCC (Ultra Large Crude Carrier) of over 300,000 D W T .

6. The cargo space is generally divided into three sections athwartships(popriječno) by means of two longitudinal bulkheads and into individual tanks by transverse bulkheads. • The maximum length of an oil tank is 20% L (L = length of vessel) and there is at least one wash bulkhead (pljuskača) if the length of the tank exceeds 10%L or 15 m. • Tanks are generally numbered from forward, each number having port (L), centre and starboard (R) compartments. • Pump rooms ( pumpna stanica) are often located aft so that power may easily be supplied to the pumps from the engine room, but ships designed to carry many kinds of oil at once may be fitted with two pump rooms placed so as to divide the cargo space into three sections.

7. Machinery spaces is positioned aft of cargo tanks and slop tanks(tank za otpadnu vodu) . • Any machinery space must be isolated from cargo tanks and slop tanks by cofferdams, cargo pump rooms, oil fuel bunker tanks or ballast tanks(balasni tank).

8. Classes of Crude Oil Tankers • Panamax -The largest size crude oil tanker that can travel through the Panama Canal (up to 70,000 DWT). • Aframax - This is a size of crude oil tanker which uses the Average Freight Rate Assessment method to calculate the cost of transportation (70,000 to 120,000 DWT). • Suezmax -The largest size crude oil tanker that can travel through the Suez Canal while Loaded (120,000 – 200,000 DWT). • Very Large Crude Carrier (VLCC) - This is the size of a large crude oil carrier (200,000-325,000DWT).

9. Panamax (60,000-70,000 DWT) • Aframax (70,000-120,000 DWT)

10. VLCCs (200,000-325,000 DWT) • Suezmax (120,000-200,000 DWT)

11. Accommodation spaces, main cargo control stations, control stations and service spaces (excluding isolated cargo handling gear lockers) must be positioned aft of all cargo tanks, slop tanks, and spaces which isolate cargo or slop tanks from machinery spaces.

12. IMO Construction Requirements for Oil Tankers • Double hulls • In 1992 MARPOL was amended to make it mandatory for tankers of 5,000 DWT and more ordered after 6 July 1993 to be fitted with double hulls, or an alternative design approved by IMO (regulation 19 in Annex I of MARPOL). The requirement for double hulls that applies to new tankers has also been applied to existing ships under a programme that began in 1995 (under old regulation 13G (now regulation 20 in Annex I of MARPOL)).  • All tankers would have to be converted (or taken out of service) when they reached a certain age (up to 30 years old). 

13. Following the Erika incident off the coast of France in December 1999, IMO Member States discussed proposals for accelerating the phase-out of single hull tankers. • As a result, in April 2001, IMO adopted a revised phase-out schedule for single hull tankers, which entered into force on 1 September 2003 (the 2001 amendments to MARPOL). The revised requirements set out a stricter timetable for the phasing-out of single-hull tankers. • In December 2003, further revisions to the requirements were made, accelerating further the phase-out schedule. • These amendments entered into force on 5 April 2005. • A new regulation on the prevention of oil pollution from oil tankers when carrying heavy grade oil (HGO)/heavy fuel oil (HFO) (teškanafta) banned the carriage of HGO in single-hull tankers of 5,000 tons dwt and above after the date of entry into force of the regulation (5 April 2005), and in single-hull oil tankers of 600 tons dwt and above but less than 5,000 tons DWT, not later than 2008.