Passenger and cargo ship: besides carrying passengers, it also carries some goods (the cabin below the waterline is used for loading as much as possible). Passenger ships and cargo ships have the same requirements as passenger ships.
General cargo ship: commonly known as general cargo ship. Grocery, also known as unified goods, refers to various items such as machinery and equipment, building materials and daily necessities. A ship that specializes in transporting bundles, packages and boxes of groceries is called an ordinary cargo ship or an ordinary cargo ship. Ordinary cargo ships have the following characteristics:
(1) The load capacity should not be very large, and the total load capacity of ocean-going general cargo ships is about 10000 tons-14000 tons; The total carrying capacity of ocean-going general cargo ships is about 5000 tons; The total load capacity of coastal general cargo ships is less than 3,000 tons (due to the variety of goods, insufficient supply, slow loading and unloading speed and long port call, the load capacity of general cargo ships is too large and uneconomical).
(2) In order to facilitate cargo loading and unloading, ordinary cargo ships are equipped with 2-3 decks. A 10,000-ton general cargo ship has 5-6 cargo holds. Most of the engine rooms are located in the middle and rear models, and some of them use the rear models.
(3) Ordinary cargo ships are equipped with the first floor, and the upper part of the engine room is equipped with a cab. The old 5000-ton general cargo ship mostly adopts the Mishima type.
(4) Many 10,000-ton general cargo ships always have deep tanks for ballast requirements, which can be used for loading liquid goods (animal and vegetable oils, molasses, etc.). ).
(5) Ordinary cargo ships are equipped with cargo lifting equipment, most of which are mainly suspenders, and some of them are equipped with hydraulic rotary cranes.
(6) Most general cargo ships have a hatch in each cargo hold, but a few general cargo ships use double-row hatches according to the needs of loading and unloading goods.
(7) Irregular general cargo ships are low-speed ships. For ordinary cargo ships, it is not economical to go too fast. Ocean-going general cargo ship is about 14 knots-18 knots, and its endurance is more than 12000 nautical miles. The speed of the general cargo ship approaching the ocean is about 13 knots-15 knots; The speed of the coastal general cargo ship is about 1 1 knot-13 knot.
(8) An ordinary cargo ship is a single propeller main engine.
Container ship: A container ship is a ship specialized in transporting container goods. It can be divided into three types: (1) full container ships are ships that transport containers exclusively and do not transport other types of goods; The semi-container ship is used as a special cargo hold for containers in the middle area of the ship, while the cargo holds at both ends of the ship are loaded with other groceries; Convertible container ship jujube is a multi-purpose ship. The cargo hold of this ship can be replaced at any time as needed. Containers and other general groceries can be loaded, which improves the utilization rate of the ship.
Ro-ro ship: cargo loading and unloading is not suspended vertically from the cargo hold on the deck, but from the cabin to the dock with a trailer or fork-type loader through the openings at the front, back or both sides of the ship and the springboard on the dock. The main advantages of ro-ro ship are: goods can be directly hauled to the receiving place without being reprinted at the port, which shortens the turnover time of goods and reduces the damage of goods.
Barge carrier: also known as mother ship: This is a kind of ship that uses the barge as a "floating container", loads the barge onto the mother ship by using the elevator and rolling equipment of the mother ship, or lifts the barge (sub-ship) from the water surface by using the lifting equipment of the mother ship, and then puts it into the mother ship, which is collectively called barge carrier. Many barge cargo ships carry container ships on deck. There are four typical barge cargo ships:
(1) Ordinary barge cargo ships are also called LASH. Like a full container ship, it is also a ship with frame structure. There are many barges in the cabin, each barge can hold four layers of barges, and two layers can be stacked on the deck.
(2) The sea bee barge is also called the west bee carrier. It is characterized by no hatch and three all-pass decks in the cabin. The loading and unloading of the barge depends on the lifting platform and trolley installed in the stern shaft to horizontally roll and load and unload the barge.
(3) The catamaran barge is also called the barge on Catama-ran (called Jane BACAT). This kind of ship is catamaran structure, the head and tail are separated, and the barge is loaded and unloaded by lifting platform and rollers on the deck.
(4) Floating dock barge, also known as Barco barge, can load barges in multiple layers by sinking the mother ship to a certain depth and floating the barges in and out through the floating dock barge.
Bulk carrier: a ship that transports bulk dry bulk cargo such as grain, coal, ore, salt and cement in bulk, which can be called dry bulk carrier or referred to as bulk carrier for short. Dry bulk carriers are single-deck ships because of their single kind of goods, no need to bundle, pack and box when loading and unloading, no fear of extrusion and convenient loading and unloading. Generally, loading equipment is not used when the total loading capacity exceeds 50,000 tons. Because the stowage factors (cargo volume per ton) of grain, coal and ore are quite different, the required cargo volume, hull structure, layout and equipment are different in many aspects. Therefore, generally speaking, only ships with similar stowage coefficients such as grain and coal are called bulk carriers, and ships with smaller stowage coefficients such as ore are called ore carriers. Ships used to transport bulk goods such as grain, coal and ore are usually divided into the following categories.
(1) A ship with a total load DW greater than 100000 tons is called the Cape of Good Hope.
(2) The total deadweight DW is 60,000 tons, which is usually called Panama type. This is the largest ship type allowed to pass through the Panama Canal. The captain should be less than 245 meters, the ship width should be no more than 32.2 meters, and the maximum allowable draft should be 12.04 meters.
(3) A portable bulk carrier with a total deadweight DW of 35,000-40,000 tons. With a shallow draft, all ports in the world can basically dock.
(4) A small bulk carrier with a total load DW of 20,000-27,000 tons. The largest ship type that can sail the five lakes in the United States. The maximum length is no more than 222.5 meters, the maximum ship width is less than 23. 1 meter, and the maximum draft is less than 7.925 meters. For ships used to transport ore, the greater the loading capacity, the lower the transportation cost. At present, the minimum total carrying capacity of ore carriers is 57,000 tons. The largest is 260,000 tons; Most of them are around 12000 tons-150000 tons. Because of the height of the ship, the loading equipment on the shore is often not high enough at high tide. Therefore, this kind of ore ship uses ballast water to adjust the draft of the ship when loading and unloading goods.
Tanker: broadly speaking, it refers to ships that transport all kinds of oil in bulk. In addition to transporting oil, we also transport petroleum products, various animal and vegetable oils, liquefied natural gas and liquefied petroleum gas. But the so-called oil tankers mostly refer to ships that transport crude oil. A ship carrying refined oil is called a refined oil ship. Ships carrying liquefied natural gas and liquefied petroleum gas are called liquefied gas ships. The greater the tanker's deadweight, the lower the transportation cost. Because of the abundant oil supply and fast loading and unloading speed, tankers can be built very large. The total deadweight of offshore oil tankers is about 30,000 tons; The total deadweight of offshore oil tankers is about 60,000 tons; The total deadweight of ocean tanker is about 200,000 tons; The total deadweight of supertankers exceeds 300,000 tons. The largest tanker reached 560,000 tons. Tankers are all single deck and single bottom structures. Because the cargo oil floats on the water surface after the cargo hold is damaged, a large amount of water will not enter the cargo hold, so the tanker generally does not have a double bottom in the cargo oil hold area except the engine room area. However, oil tanker accidents will cause pollution. In recent years, some large oil tankers have double bottoms or double hulls.
Liquefied gas carrier: a ship specialized in transporting bulk liquefied petroleum gas and natural gas. Some people also call it a special tanker. According to the temperature and pressure of liquefied gas during transportation, it can be divided into three types:
(1) pressure liquefied gas carrier: This kind of liquefied gas carrier is suitable for short-distance transportation of a small amount of liquefied gas at sea. At normal temperature, the gas is pressurized to the liquefaction pressure, and the liquefied gas is stored and transported in a high-pressure container. This mode of transportation is relatively simple in hull structure and operation technology, but the container is bulky and the capacity utilization rate of the ship is low, which is not suitable for building large high-pressure containers.
(2) Low temperature and pressure liquefied gas carrier: The temperature of liquefied gas is controlled below normal temperature 45℃ but higher than the boiling point of liquefied gas, and within this temperature range, the gas is pressurized to a liquid state for transportation. When transported in this way, it is necessary to control the temperature and pressure of liquefied gas, and the cabin should be insulated and equipped with refrigeration equipment.
(3) Low temperature liquefied gas carrier: at atmospheric pressure, the gas is cooled to below the liquid temperature for transportation. The ship is equipped with temperature and pressure control devices. It is suitable for transporting liquefied gas in large quantities, and there are many liquefied gas carriers of this type at present.
Dual-purpose ship: a dual-purpose ship or a three-purpose ship, which can carry both crude oil and bulk cargo or ore. Special ships, such as bulk carriers, ore carriers and oil tankers, have a relatively large load capacity, but because of the single type of goods transported, they can't carry other kinds of goods when they return, so they have to fly empty. Dual-purpose ships can load different kinds of goods on the round-trip voyage according to the changes of goods types. There are two main types of dual-purpose ships:
(1) The mineral/oil dual-purpose ship jujube is used to transport ore and crude oil. Referred to as 0. 0 ship (ore/oil), the middle cargo hold of this ship is relatively narrow, accounting for 40%-50% of the cargo hold of the whole ship. When transporting ore, it is placed in the middle cargo hold, and when transporting crude oil, it is placed in the side cabins and the middle cabin on both sides.