East Coast. Their smaller size allows them to access most ports across the globe. A GP tanker can carry between 70, barrels and , barrels of motor gasoline 3. Long Range LR class ships are the most common in the global tanker fleet, as they are used to carry both refined products and crude oil. These ships can access most large ports that ship crude oil and petroleum products. An LR1 tanker can carry between , barrels and , barrels of gasoline This ship size is popular with oil companies for logistical purposes, and, therefore, many ships have been built within these specifications.
The distance from the bottom of the ship to the top of the mast is approximately 65 meters [equivalent to an story building], and the draught [the depth from the water surface to the bottom of the ship] exceeds 20 meters in a fully loaded condition. The picture below is the "Keiyo sea berth" discharging facility locate in Tokyo Bay, where VLCCs call at the port a year, to supply crude oil to four oil refineries on the Tokyo Bay area through submarine pipelines.
The light blue area in the below illustration is the ballast tank [tanks for seawater to adjust the balance of the ship], and the green area is the cargo tank where crude oil is loaded, to keep the cargo from spilling into the sea even if the outer panels are damaged. The inside of the hull is usually divided into 17 tanks, and the ship can load multiple grades of crude oil at the same time without mixing. For loading and discharging operations, the ship tanks and the shore tanks are connected by pipelines and hoses.
Usually, The VLCCs have three cargo pumps, and each pump can discharge about 35, barrels [5, cubic meters] of crude oil per hour. Then, an Olympic-sized pool [50x25x2 meters] of crude oil can pump up in less than 30 minutes.
Double hull structure: Cargo tanks green part protected by double skin. The main engine of the VLCC, which generates the propulsion power of the ship, is a two-cycle diesel engine with six or seven cylinders. It is a huge structure not comparable with engines of automobiles or trucks. The pistons have millimeters diameter [bore], and the stroke exceeds 3 meters. The engine displacement is more than 10, liters with a maximum output of 38, horsepower and revolves the propeller 70 to 80 times per minute.
Then the VLCC can navigate about 15 knots [28 kilometers per hour] at sea. Since the VLCC was first introduced in the s to improve transport efficiency by upsizing tankers, the typical specifications of VLCCs have been established over the past 50 years. The world's largest merchant ship, Knock Nevis, delivered in , was meters in length and 69 meters in width and was able to load more than 4 million barrels of crude oil, doubled the capacity of a typical VLCC.
However, due to their extraordinary size, these ULCCs could call only limited ports and could not pass through narrow and shallow channels like the Strait of Malacca, which made their operation less efficient in reality. It seems that bigger is not always better, but that each ship type has its optimal size, and there is a practical limitation for upsizing.
LONDON Reuters - Traders are storing an estimated record million barrels of oil on ships - double the level from two weeks ago as they seek to tackle a glut of stocks created by a slide in global demand from the coronavirus, shipping sources say. At the same time traders have rushed to find storage on land and at sea in what is believed to be the biggest oil glut in history.
Shipping sources said oil held in floating storage on tankers had reached at least million barrels including 60 supertankers, known as very large crude carriers VLCCs , which can each hold 2 million barrels.
Smaller tankers were also being used, which was also boosting volumes being held at anchor, they added.
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