English in Ship and Ocean Engineering
Unit 1 Ship Types
The Family Tree of Merchant Ships
Group 1: Ocean Going Ships
Passenger Ships
Passenger liners
Passenger and cargo ship
Cargo carrying ships ( tramp or liner)
General cargo ship
Multipurpose (general purpose) ship
Bulk carriers ( combination carrier, collier, ore carrier, OBO, timber carrier) Tankers, divided into
Crude oil carrier: VLCC ULCC
Chemical tanker, product carrier
Container ships, including
Conventional containership
Hatchcoverless containership
Liquified gas carrier, including:
LPG/LNG
Refrigeration cargo ship( reefer)
RoRo ship
Barge carrier
LASH lighter aboard ship SEABEE
Group 2: Sea and coastal ships, inland-waterway ships(近海、沿海、和内河船)
Ferries
Passenger ships(conventional liner, catamaran, hydrofoil)
Hovercraft( air cushion vehicle: ACV)
Cargo vessels
Cargo – passenger ships
Pleasure boats
Barge
Group 3: subsidiary ships
Working ships（工程船）
Tug(拖轮), floating crane（浮吊）, dredger（挖泥船）, salvage ship（打捞船）, drilling vessel（钻井船）, pile-driver（打桩船）, pipe line layer（敷管船）, cable layer（布缆船）, dike layer（筑堤船）, icebreaker（破冰船）, firefighting ship（消防船）,buoy tender（航标船）, research ship （调查船）, split hopper barge（开体泥驳）。
Fishing Vessel:
Trawler, fish factory ship, seiner
Others
Supply ship(water, fuel oil)
Training ship
Navy Ships
Navy armament
Gun/ heavy gun, Depth bomb/charge, mine, torpedo, missile, armed aircraft,
Group 1: War ships
Subgroup 1: Surface combatant ship
Patrol boat, bun boat, torpedo boat, guided missile boat, submarine hunter, frigate, destroyer, cruiser, helicopter carrier, aircraft carrier.
subGroup 2: undersea ships
Submarine(conventional powered submarine, unclear powered submarine)
Group 2: Naval Auxiliary Ships
Landing ship(boat, Minehunter(mine-sweeper),minelayer, combat stores ship, ammunition ship, surveying ship, commuter boat
课文阅读
The development of ship types over the years has been dictated very largely by the nature of the cargo. The various designs can, to some extent, be divided into general cargo, bulk cargo and passenger vessels.
The general cargo carrier is a flexible design of vessel which will go anywhere and carry anything. Special forms of the general cargo carrier include container ships, roll-on roll-off ships and the barge carriers, bulk cargo may be liquid, solid, or liquefied gas and particular designs of vessel exist for the carriage of each.
Passenger – carrying vessels include cruise lines and ferries. Many special types of vessel exist which perform particular functions or are developments of particular aspects of technology. These include : multi-hull vessels, hydrofoil and hovercraft.
General cargo ships
The general cargo ships have several large clear open cargo-carrying spaces or holds. One or more separate decks may be present within the holds and are known as “tween decks”. These provide increased flexibility in loading and unloading and permit cargo segregation as well as improved stability. Access to these holds is by openings in the deck known as hatches.
Hatches are made as large as strength considerations permit in order to the amount of horizontal movement of cargo within the ship. Hatch covers are, nowadays, made of steel althouth older vessels used wood. The hatch covers must be watertight and rest upon coamings around the hatch. The coaming of the upper or weather deck hatches are a reasonable height above the deck to reduce the risk of flooding in heavy seas.
Some form of cargo handing equipment is always fitted which may take the form of derricks and winches or deck cranes. Deck cranes are fitted to many vessels since they reduce cargo handing times and manpower requirements. Some ship have special heavy-lift derrick fitted which may serve one or more holds.
A double bottom is fitted along the ship ’s length and is divided into various tanks. These tanks may be used for fuel or lubricating oil, fresh water or ballast sea water. Fore and aft peak tanks are also fitted and may be used to carry ballast or to suitably trim the ship.
Deep tanks are often fitted and can be used to carry liquid cargoes or water. The water ballast tanks may be filled when the ship is only partially loaded in order to provide as sufficient draught for stability and total propeller immersion .
There is usually one hold aft the accommodation and machinery space. This arrangement improves the trim of the vessel when it is partially loaded. The range of size for general cargo
ships is currently form 2000 to 15000 displacement tones with speeds form 12 to 18 knots.
Refrigerated cargo ships
The refrigerated cargo ship differs from the general cargo ship in that it carries perishable goods. A refrigeration system is therefore necessary to provide low temperature holds for these cargoes. The holds and the various tween decks are insulated to reduce heat transfer. The cargo may be carried frozen or chilled and various holds may be at different temperatures according to cargo requirements.
This type of vessel is usually faster than a general cargo ship, having speeds up to 22 knots. It is essentially a cargo liner having set schedule and sailing between fixed terminal ports. Up to twelve passengers may be carried on some of these vessels.
Container ships
A container is re-usable box of 2435 mm by 2435 mm section, with length either 6065, 9123 or 12100mm. containers are now used for most general cargoes and liquid-carrying versions also exist. Refrigerated versions are in use which may have their own independent refrigeration plant or be supplied with cooled air form the ship’s refrigeration system.
The cargo-carrying section of the ship is divided into several holds each of which has a hatch hatch opening the full width and length of the hold. The containers are racked in special frameworks and stacked one upon the other within the hold space.
Cargo handling is therefore only the vertical movement of the containers by a special quayside crane. Containers may also be stacked on the flush top hatch covers. Special lashing arrangements are used to secure this deck cargo.
The various cargo holds are separated by a deep web-framed structure to provide the ship with transverse strength. The ship structure outboard of the container holds on either side is a box-like arrangement of wing tanks which provides longitudinal strength to the structure. These wing tanks may be used for water ballast and can be arranged to counter the heeling of the ship when discharging containers. A double bottom is also fitted which adds to longitudinal strength and provides additional ballast space.
The accommodation and machinery spaces are usually located aft to provide maximum length of full-boded ship for container stowage . Cargo-handing equipment is rarely fitted, since these ship travel between specially equipped terminals to ensure rapid loading and discharge. Container ship size vary considerably, with container carrying capacities form 1000 to 2500 TEU ’s or more. The twenty foot equivalent unit(TEU) represents a 20ft(6055mm) standard container. Container ships are much faster than most cargo ships, with speeds up to 30 knots. They operate as liners on set schedules between fixed ports.
Roll-on roll-off ships
This vessel was originally designed for wheeled cargo, usually in the form of trallers. The cargo could be rapidly loaded and unloaded by stern or bow ramp and sometimes sideports form samaller vehicles. The loss of cubic capcity due to undercarriages and clearances has resulted in many roll-on roll off vessels being also adapted to carry containers.
The cargo-carrying section of the ship si a large open deck with a loading ramp usually at eh after end. Internal ramps lead from the loading deck to the other tween decks spaces. The cargo may be driven aboard under its own power or loaded by straddle carriers or fork lift trucks.
One or more hatches may be provided for containers or gerneral carog and will served by on or more deck cranes. Arrangements may be provided on deck stowing containers. Some roll-on
roll-off vessels also have hatch covers to enable loading of lower decks with containers. Where cargo(with or without wheels) is loaded and discharged by cranes the term lift on lift off(lo-lo) is used.
The ship’s structure outboard of the cargo decks is a box-like arrangement of wing tanks to provide longitudinal strength. A double bottom is also fitted along the complete length. The accommodation is lacted aft and also the low-height mahcinery space. Only a narrow machinery casing acturally penetrates the loading deck sizes range considerabley with about 16,000 dwt (28000 displacemetn tonne) being quite common. High speeds in the region of 18-22 knots are usual.
Section tier row
Lecture 1: The Criterion of Translation
18
Navigation system elements
From a navigational point of view, the safety of ship underway depends on the ability of personnel to determine accurately the position of the ship, to keep on a desired course, to determine presence of other vessels in the area, and to make any such vessels aware of their own presence. To accomplish these objectives, the ship must be provided with essential navigating equipment.
International convention establishes the minimum navigation equipment standards which require a ship to be equipped with the following, a marine radar system, a radio direction finder, a gyrocompass, and echo- depth sounding device, a radio telephone or radio telegraph, and the necessary nautical publications as appropriate for the intended voyage. Certain items of navigation equipment are specified in detail by international agreement. For most of this items. The primary purpose of establishing requirements is to assure that equipments such as navigation lights and sound signals will be uniform and recognizable by all ships.
Other aids to navigation consist of Doppler sonar, satellite communication receivers, Loran, and Omega. The Doppler sonar consist of keel mounted transducers which send down pulsed sonic beams and convert the return signals into displays of ship speed, ahead and transverse. The read- out have display arrows showing direction of bow and stern movement. These permit a quick visual and quantitative display of translational and rotational movement relative to the bottom. This is of particular use for large ship which make up to sea buoys or com to a pier, because in the very low speed range precise docking maneuvers are very difficult to judge.
Satellite navigation signals require a special shipboard antenna and compute. These are commercially available, and use a satellite signal available roughly every hour and a half. The result is the ability ot have latitude and longitude of the position of the ship in the open seas about every hour and a half precise to within one or two nautical miles.
The loran set is useful in determining an accurate position electronically use is becoming commonplace on almost all merchant ships. It is generally located in the chart room. A Loran set is particularly sensitive to vibration and its location in the chart room should be selected with care so as to minimize the effects of vibration and thus reduce maintenance costs.
The omega receiver set is useful in determining position-fixing information electronically and provide accuracy equivalent to that obtained form Loran. The system is partially in operation now and covers most of the northern hemisphere. When the last station is completed and coverage areas and accuracy validated, it is expected that most of the open seas areas around the globe will
be covered with the eight stations. The receiver set may be located in the chart room, but is commonly found in the pilothouse