SHIP TYPE

A ship's size and capacity can be described in two wayslinear dimensions or tonnages. Each is completely different yet interrelated. Ocean-going ships are classified by the type of cargo they carry and their size expressed as DWT or deadweight tonnage. Deadweight tonnage is the weight (in tons) of all the cargo, fuel, dry provisions, supplies, etc. carried on board the ship. Deadweight tonnage is a good indication for ship owners and clients of how much revenue the ship is capable of generating. There are at least six different ways a ships tonnage is measured in regards to ships, MODUs, and other types of commercial ships.Type of ships tonnage measurements: Displacement TonnageDisplacement tonnage is nothing more than the total weight of the volume of water a ship displaces when it is sitting in the water.

Standard Displacement TonnageStandard displacement tonnage is basically the same thing as displacement tonnage with one minor difference. When calculating standard displacement tonnage, you subtract the weight of any fuel and potable water carried on board the ship.

Deadweight TonnageDeadweight tonnage is the weight (in tons) of all the cargo, fuel, dry provisions, supplies, etc. carried on board the ship. In other words, it is the displacement tonnage of the ship minus the lightweight tonnage. Deadweight tonnage is a good indication for ship owners and clients of how much revenue the ship is capable of generating.

Lightweight TonnageLightweight tonnage is best described as the weight of the ship when it was built in the shipyard including all framing, machinery, decking, etc. However, lightweight tonnage does not include the weight of any consumable such as fuel, water, oil, or supplies.

Gross Registered TonnageGross registered tonnage is a measurement of volume of all enclosed spaces on a ship with 100 cubic feet = to one ton. For instance, if the total cubic volume of all the enclosed spaces on aship were 340,000 cubic feet, the gross registered tonnage will most likely be 3400 gross tons (340,000 cu. feet/100 cu feet/ton = 3400 Gross Tons).

Net registered TonnageNet registered tonnage is also a measurement of volume however you only consider the volume of actual cargo storage areas when dividing the cubic volume in feet by 100 to get your tonnage. This includes any tanks, cargo holds, etc. that are normally used for transporting cargo.

In some cases, a ship is classified by its length and width. Since each classification society has slightly different standards, the size range for each ship type may vary. Below is the explanation of ship dimension:

A ship'sLength Overall [LOA]is measured in feet and inches from the extreme forward end of the bow to the extreme aft end of the stern. Watercraft operators must be familiar with this and similar dimensions to safely maneuver the ship. The dimension is commonly found in lists of ship's data for each ship.A ship's length is sometimes given asLength Between Perpendiculars [LBP]. It is measured in feet and inches from the forward surface of the stem, or main bow perpendicular member, to the after surface of the sternpost, or main stern perpendicular member. This was believed to give a reasonable idea of the ship's carrying capacity, as it excluded the small, often unusable volume contained in her overhanging ends. On some types of ships this is, for all practical purposes, a waterline measurement.A ship'sLength on Load Waterline [LWL]is an important dimension because length at the waterline is a key factor in the complex problem of speed, resistance, and friction. On ships with a counter stern, the LWL and LBP can be the same or about the same. On a ship with a cruiser stern, the LWL is greater than the LBP.A ship's width or, more properly, a ship's breadth is expressed in a number of ways. A ship's extreme breadth, commonly called beam, is measured in feet and inches from the most outboard point on one side to the most outboard point on the other at the widest point on the ship.The depth of a ship involves several very important vertical dimensions. They involve terms like freeboard, draft, draft marks, and load lines. The ship's depth is measured vertically from the lowest point of the hull, ordinarily from the bottom of the keel, to the side of any deck that you may choose as a reference point. Therefore, it has to be stated in specific terms such as depth to upper deck amidships. It is impractical to measure depth in any other way, since it varies considerably from one point to another on many ships. For example, the depth is greater at the stern than amidships. Thedraft(American) ordraught(British) of a ship'shullis the vertical distance between thewaterlineand the bottom of the hull (keel), with the thickness of the hull included; in the case of not being included the draft outline would be obtained. Draft determines the minimum depth of water a ship or boat can safely navigate.Types of cargo ships are: AframaxAn ocean-going crude oil tanker ship of standard size between 80,000 and 119,000 DWT that is the largest crude oil tanker size in the AFRA (Average Freight Rate Assessment) tanker rate system. HandymaxA handymax is typically 150-200 meters (492-656 feet) in length, though certain bulk terminal restrictions such as those in Japan mean that many handymax ships are just under 190 meters in overall length. Modern handymax designs are typically 52,000-58,000 DWT in size, have five cargo holds and four cranes of 30 metric ton lifting capacity. HandysizeA small bulk or oil tanker ship that is suited to tie up at a T2 type pier. These ships are a maximum of 10,000 to 30,000 DWT. These ships are more maneuverable and have shallower draft than larger ships and therefore make up the majority of the world's ocean-going cargo fleet. PanamaxAn ocean-going cargo ship of the maximum size possible to pass through the locks of the Panama Canal, which are 1000ft long by 110ft wide and 85ft deep. These ships are typically of 50,000 to 80,000 DWT, 965ft (290m) in length; 106ft. (32.3m) beam; and 39.5ft (12.04m) draft. Panamax is the maximum size of oil tanker. SuezmaxAn ocean-going cargo ship of the maximum size possible to pass through the locks of the Suez Canal in Egypt. This standard has evolved over time. Prior to 1967, a Suezmax was a maximum of 80,000 DWT. The canal was closed between 1967 and 1975 because of the Israel-Arab conflict. Upon reopening in 1975, after many modifications to the locks and canal itself, the maximum was increased to 150,000 DWT. After the further deepening of the Suez Canal from 18 m (60 ft) to 20.1 m (66 ft) in2009, a Suezmax of up to200,000 DWTor even more can easily pass through it. Seawaymax:The term Seawaymax refers to ships which are the maximum size that can fit through the canal locks of the St Lawrence Seaway. Seawaymax ships are 740 feet in length, 78 feet wide, (maximum 226 m length, 24 m beam) and have a draft of 26 feet (7.92 m). A number of Lake freighters larger than this size cruise the Great Lakes and cannot pass through to the Atlantic Ocean. The size of the locks limits the size of the ships which can pass and so limits the size of the cargoes they can carry. The record tonnage for one ship on the Seaway is 28,502 tons of iron ore while the record through the larger locks of the Great Lakes Waterway is 72,351 tons. Most new lake ships, however, are constructed to the Seawaymax limit to enhance versatility by allowing the possibility of off-Lakes use. Capesize:Refers to a rather ill-defined standard which have the common characteristic of being incapable of using the Panama or Suez canals, not necessarily because of their tonnage, but because of their size. These ships serve deepwater terminals handling raw materials, such as iron ore and coal. As a result, "Capesize" ships transit via Cape Horn (South America) or the Cape of Good Hope (South Africa). Their size ranges between 80,000 and 175,000 DWT. Due to their size there are only a comparatively small number of ports around the world with the infrastructure to accommodate such ship size. Ultra Large Crude Carrier (ULCC)An ocean-going crude oil tanker of 300,000 to 550,000 DWT. These are the largest ships in the world and are used for carrying crude oil on long haul routes from the Arabian Gulf to Europe, America and the Far East, via the Cape of Good Hope. These ships require custom built terminals for loading and discharge. Very Large Crude Carrier (VLCC)An ocean-going crude oil tanker of 200,000 to 299,999 DWT. These ships have greater flexibility than ULCCs due to their smaller size and are used extensively in the Mediterranean, West Africa and the North Sea. These ships can sometimes be ballasted through the Suez Canal.

Below are the illustrations of the ship size based on its DWT:

LOADING-UNLOADING OIL CARGO SHIP

Operations aboard oil tankers are governed by an established body of best practices and a large body of international law.Pre-transfer preparationBefore any cargo transfer, a Chief officer develops a transfer plan, which details all the specifics of the operation, such as the amount of cargo about to be moved, which tanks are to be cleaned and how the ship's ballast will change. The next step is the pre-transfer conference which covers issues such as: What products will be moved In what order will the products be moved Names and titles of all key personel Particulars of shipboard and shore equipment Critical stages of the transfer Federal, state, and local regulations in effect Emergency and spill-containment procedures Watch and shift arrangements Shutdown procedures

When the conference is completed, the person in charge of the ship and the person in charge of the shore installation go over the final inspection checklist. In the U.S., this is called aDeclaration of Inspectionor DOI, outside of the U.S. it is called theShip/Shore Safety Checklist. This checklist includes: Proper signals and signs are displayed The vessel is securely moored A language for all communication is chosen All connections are secure Emergency equipment is in place No repair work is ongoing.

Loading cargoLoading an oil tanker consists primarily of pumping cargo into the ship's tanks. As oil enters the tank the vapors inside the tank are expelled depending on the local regulations. They are either expelled into the atmosphere or discharged to the pumping station. It is also common for the ship to move water balast during the loading of cargo to maintain proper trim.Loading starts at a slow pace and at a low pressure to be sure that all the connections are secure and that the equipment is working properly. Then a steady pressure is achieved and held until the "topping-off" phase when the tanks are nearly full. As the tanker becomes full, crew members open and close valves to direct the flow of product and maintain close communication with the pumping facility to decrease and finally stop the flow of liquid.

Unloading cargoThe process of unloading oil off the tanker is similar to the loading process but it has some key differences. The first step of the unloading has the same pre-transfer procedures as does the loading. While pumping the cargo, tank levels are monitored and key location are constantly watched. Under the direction of the person in charge, crew members open and close valves to direct the flow of product and maintain close communication with the receiving facility to decrease and finally stop the flow of liquid.Tank clearingFrom time to time for various reasons it is required for the tanks to be cleaned. One of the common reasons is the changes in the type of cargo carried inside the tank. Also, when tanks are to be inspected or maintenance must be performed within a tank, it must be not only cleaned, but made "gas-free."Most crude oil tankers have a special oil washing system (COW) that is an integral part of the cleaning process. The COW system moves part of the cargo through fixed tank cleaning system to remove asphaltic deposits and wax.Tanks that carry less viscous cargoes are washed with water. Fixed and portable water washing systems exist. Some systems use rotating high-pressure water jets to spray hot water on all the internal surfaces of the tank. As the spraying takes place, the liquid is pumped out of the tank.After a tank is cleaned it is sometimes freed of gases. This is done by blowing fresh air into the tank. The tank's atmosphere is monitored by specially trained personnel that use hand-held indicators which measure the hydrocarbons present in the tank. When the percentage of hydrocarbons drops below a certain value, the tank is declared gas-free.After a tank is gas-free, it can be further hand-cleaned in a process referred to as "mucking." This task is generally done by able seamen and deck officers using tools such as mops, buckets, rags and sponges.

DOCK

There are 3 types of dock, they are wharf, pier, and jetty. Jetty is usually an open structure construction while wharf and pier can be both open or closed structure construction. Below is the cross section of a dock:

Apron acts as the transition from the ship to the container yard or from the container yard to the other means of transport (truck, etc.). Container yard is used to store the cargo either before loading to the ship or waiting to be loaded to the truck after being unloaded from the cargo ship.Wharf is a type of dock which is paralleled to the coast line, can be build juts out into the water or just at the edge of body water. Wharf usually used for cargo container ships. Pier is a dock built on the shore and positioned perpendicular to the coast line. The difference with wharf is that with pier the ships can berth at both sides.

Jetty is a dock that juts out into the water so that it reaches the certain level of depth. Jetty is usually used for tanker ships because it needs deeper depth. Jetty is usually paralleled to the coast line and connected by the bridge that is perpendicular to the coast line and jetty.

BULK TERMINAL

Definition: A facility used primarily for the storage and/or marketing of petroleum products, which has a total bulk storage capacity of 50,000 barrels or more and/or receives petroleum products by tanker, barge, or pipeline.Bulk terminal stores the oil (CPO, etc.) from ship tanker before going to the refinery process or after being processed and waiting to be shipped again. The facilities available at the bulk terminal are: Weighbridge, by weighing the vehicle both empty and when loaded, the load carried by the vehicle can be calculated. Oil receiving station, before transferring the oil to the storage tank, they are kept at the oil receiving station. The purpose is to achieve the efficiency of the pump.

Storage tank, to store the oil before going to the refinery process or when waiting to be shipped after being processed. Boiler, to keep the oil at the desired temperature. Pipe and pump, to deliver from and to the ship or from and o the refinery plant. Water treatment plant, to process the water for domestic purpose or for boiler activity.