Main ship types:
-
- Bulker
- Tanker
- Container
- Offshore
- Passenger /Ferry
- Ro-Ro
(1)Bulker
A bulk carrier is a ship designed to
transport dry or liquid bulk cargo, such as grains, coal, iron ore, and cement. Over the years this ship type have grown in size and sophistication. Today’s bulkers are specially designed to maximize capacity, safety, efficiency, and to be able to withstand the rigors of their work. Bulkers represents about 40% of the worlds merchant fleet and the development of freight prizes are often used as an indicator of the world economy through the Baltic Dry Index.
Bulker Size & Classes
Bulker are categorized into four main classes, Handysize, Handymax/Supramax, Panamax, Capesize that describe their size. The unit used for defining size of bulkers is DWT (dead weight tons) also known as “metric dead weight tons” and describes how much weight a ship can carry.
Handysize: DWT 10 000 – 35 000
Handymax/Supramax: DWT 35 000 – 59 000
Panamax: DWT 60 000 – 80 000
Capesize: DWT 80 000 ≤
Further, there are also a number of abbreviations to describe bulk carriers especially in the lager segments with terms like “VLOC”(very large ore carrier), “VLBC” (very large bulk carrier), “ULOC” (ultra large ore carrier), “ULBC” (ultra large bulk carrier).
Bulker types & design
General Design
A bulker is designed with one (smaller vessels) or several cargo holds and it is purpose (the type of cargo it will carry) that defines the design of the ship. Speed of the vessels is between 13 to 15 knots and depending on size they can be equipped with either two-stroke or medium speed engines. Hatch covers that covers the cargo holds covers about 60-70% of cargo holds length. In order to maximize loading and off loading efficiency the hatches should be as large as possible but it also presents structural problems and increased stress to the hull.
Bulker types
Bulkers can be split into two main categories “Geared Bulk Carriers” and “Gearless Bulk Carriers”. A “Geared” carrier means that the ship is equipped with equipment for loading and off loading a port. Thus, this type is not dependent on land based equipment. A “Gearless” carrier is the opposite, a ship that need assistant from equipment installed at port
(2)Tanker
A tanker is ship that is designed to transport liquids in bulk. Tankers, like other ship types, are today highly specialized and exists in number of varieties and sizes. From small self propelled barges up to ULCC (ultra large crude carrier). An example of what Tankers are designed to carry is: crude oil, Petroleum, liquefied natural gas, liquefied petroleum gas, Bitumen, molasses, wine and chemicals (i.e. ammonia, chlorine). The tanker segment represents about 30% of the worlds total merchant fleet.
Tanker size and classes
Petroleum tankers are categorized into the following classed that determines theirs size in DWT (Dead Weight Tons).
Seawaymax: DWT 10 000 – 60 000
Panamax: DWT 60 000 – 80 000
Aframax: DWT 80 000 – 120 000
Suezmax: DWT 120 000 – 200 000
VLCC (very large crude carrier): DWT 200 000 – 315 000
ULCC (ultra large crude carrier): DWT 315 000 – 520 000
Tanker Design and Types
Design
The design of Tanker ship is similar to a Bulker with the exception that the cargo holds have been replaced with tanks. Machinery either two our four stroke engines depending on size and design of the vessel. In most cases HFO (heavy fuel oil) is used as fuel for propulsion but in some cases (like on LNGs) natural gas is used instead of HFO. Design speed of the vessels is normally between 10 – 18 knots. For on- and offloading of the vessel tankers are equipped with a cargo pump system that is closely monitored due to risk of fire.
Asphalt/Bitumen Carriers
Are ships that specially designed to carry asphalt/bitumen products. Characteristics of those ship is that they are designed with “floating tanks” which means that the tanks are allowed to expand due to high temperature of the product they carry, up to 260°C. Tanks are sometimes insulated to minimize heat losses. Size of a bitumen carrier is in the smaller segment (<10 000 DWT) typically between 1 000 – 6 000 DWT.
Bunker Tanker
Is a ship designed to supply fuel to ships offshore. Bunker tanker are smaller vessels from 100 – 5 000 dwt and the design is the sames as product tankers.
Crude Oil Tanker
Crude oil tankers are dedicated to transport crude
oil from offshore oil plants (oil platforms) or oil fields to refineries. Ships in this category falls belongs to the real “giants of the sea” and the worlds largest ships could be found among crude oil tankers. The Seawise Giant, later the Happy Giant, Jahre Viking and Knock Nevis is the longest ship ever build it measured 458 meter long and 68 meter wide (beam), draght of 24,6 and depth 29,8 meters. It had a capacity of 564 763 DWT and top speed 16knots. From top speed to stop it required 8 000 meters or 5 1/2 mile. The ship is not in service anymore as it was scrapped in 2010.
LNG/LPG
ships that specially designed to transport liquefied gas
Product Tankers
Is a ship designed for transporting refined products from the refineries such as gasoline, diesel oil and aviation fuel. Product tankers are available from small tanker barges up sizes of 170 000 DWT and is the most common tanker type.
Chemical Tanker
Is a ship that is designed to transport different kinds of chemicals but are also able to transport the same products as the Product Tanker. A chemical tanker is in most cases more advanced than the Product Tanker when comes to the cargo handling system as have to avoid mixing of the products it is transporting.
Other Tankers
Apart from whats been described above there a number of specialized tankers like Wine tanker, Fruit Juice Tanker, Water Tanker, Sulphur Tankers and Storage Tanker.
(3)Container
A container ship is a ship that carry all of its cargo in standardized truck-size containers. A container is either 20 or 40 feet long, 8 feet wide and 8 or 8,6 feet high. To increase revenues, “high cube” containers with heights of 9’6″ have come into common use. Fortunately, most container ships can carry containers of mixed heights without significant difficulty. Containerships generally carry a mix of 20′ and 40′ containers, and some are fitted for deck stowage of 45′ and 48′ lengths.
Over the years goods transported in containers has increased and is increasing due to the flexibility and easy of cargo handling at port. One example is that containers are taking over the Reefer market. Today, approximately 90% of non-bulk cargo worldwide is transported by container. Containers ships is also many time referred to as “Box-Ships”
Container ship size & Classes
Container ships have constantly been growing in size and today they are seriously competing with the ULCC Tankers of being the largest ships in the world. It is the economy-of-scale that is driving the growth in ship size. Unlike the Bulker and Tanker segment Container ships are defined by its capacity in number of containers they able to carry. The term used is TEU and is an abbreviation from Twenty Feet Equivalent Units. One of the first container ships, the US Ideal X, owned by Malcom Mclean, had a capacity of 58 containers in on its first voyage in April 1956. Today´s largest Container ship deveivered 2007, the Emma Maersk, officially have a capacity of 11 000 TEUs and is 357 meters long & 56 m wide. Industry sources however estimates the capacity to be between 13 000 – 15 000 TEUs. Today the industry is looking into construction even larger ships, 18 000+ TEUs.
Panamax: ≈4 500 – 5 000 TEU
Post Panamax: ≈5 000 – 10 000 TEU
Suezmax: ≈10 000 -15 5000 TEU
Post Suezmax: ≈15 500 TEU< (This ship type does not exist yet but is being discussed)
Container Designed & Type
General Design
Containers are generally designed with either one or two medium speed engines or slow-speed (2-stroke) engines depending on ship size. Design speed is about 15 – 27 knots. In general bigger ships needs go faster due longer port stay for offloading. Smaller vessel can be (geared) equipped with equipment for self offloading of containers while the larger gearless ships is dependent on port equipment.
ULCS
Abbriviation of “Ultra Large Container Ship” and today are able to carry more than 10 000 TEU. Speed is usually 25 + knots and the vessels are gearless.
Container Feeder vessel
Typically between 500 – 1 700 TEU and operates between ports within a continent i. e. the northern european ports. Design speed is 15 – 21knots and there are both geared and gearless types.
(4)Offshore
The offshore segment it self is more than big enough for site of its own (and there are a few) however I will only focus on the ship types used for supporting this industry. The offshore vessel segment has increased over the past decade due to extensive exploration of new fields in deeper waters than ever before. Vessels in this segment are highly specialized and I will only briefly go through most common types.
The offshore market is characterized by vessels built for assistance in oil extraction and exploration at sea. The specifications of the vessels depend on whether they are built primarily to move drilling rigs and their anchors, to deliver goods and supplies to oil rigs, to act as safety and fire-fighting vessels (stand-byvessels) or for other purposes required to maintain and expand oil production at sea. The North Sea and the Gulf of Mexico are the largest markets for offshore vessels, but other areas such as western Africa, Canada, the Far East and Brazil employ an ever-increasing share of the global fleet.
Apart from the more common offshore ship types, there exist numerous types of offshore related ships that have very specific characteristics.
These include:
(5)Passenger /Ferry
Passenger ships is defined as ship specially
designed for carrying 12 or more passengers. The first ships, boats that we today have records of where actually use for crossing a river or lake. Still ships are used for same purpose all over the world. In this category ships could be found as either ships used for pure passenger transport or ships designed for pure recreational purposes that are maybe more like a “floating resorts” than ships. There are of course a lot of variants in between the two extremes.
Ship Design & Types
General Design
It is almost impossible to talk about any general design in this segment as Passenger ships and Ferries exist i so many variants. However they do share one thing, they are designed to carry passengers. These ships could found as small Ferries crossing for crossing a channel, river or a lake or as the ship described above (the independence of the sea). Propulsion of Passanger ships could from Gas turbine, diesel engines and they can be equipped with either conventional propellers or water-jet units. Design speed is from 6 up to 40+ knots. The could also be found as single hull, multi-hull (i.e. catamaran) hydrofoil and hovercraft.
Cruise ship
This ship type is specially designed for “enjoying-your-stay-on-board” purposes. Todays highly developed cruise liners are more close to “floating resorts” than conventional ships. The activities you won´t find on an modern cruiser is not worth looking for. From technical perspective they are highly advance ships fitted with most sophisticated equipment available in the market. Modern cruisers sometimes use diesel-electric pod propulsion for superior maneuverability when entering ports. There is also pressure on on the ships to “clean” and many times visits sensitive and some time protected archipelagos and seas.
Ferry
A ship that is designed to transport people between different destinations. Ferries for longer trips are becoming more like the cruiser in order to entertain its passengers during the cross over.
RoPax
Is designed to carry cargo and passengers. RoPax is an abbreviation between Roll-On “Ro-” and “Pax” which in turn is an abbreviation of passenger. There are a lot of variants of this ship type e. i. single hull or multi hull pax/vehicle, pax/vehicle, train, truck etc..
Hovercraft
A hovercraft (air-cushion vehicle, ACV) is a 
craft capable of travelling over surfaces while supported by a cushion of slow moving, high-pressure air which is ejected against the surface below and contained . Because they are supported by a cushion of air, hovercraft are unique among all other forms of ground transportation in their ability to travel equally well over land, ice, and water.
Passenger Hydrofoil
A hydrofoil ship is a ship with “wings” mounted underneath the hull that lifts the ship partially out of the water . The first ship boat with this technique was built in 1909. This ship is not so common as ship types conventional hull designed but are used in some places.
(6)Ro-Ro
RoRo (Roll-on/roll-off) ships are vessels designed to carry wheeled cargo such as automobiles, trucks, semi-trailer trucks, trailers or railroad cars that are driven or towed on and off the ship on their own wheels. This ships “Roll-on” and “Roll-off” its cargo through its built-in ramps. The ramps could be located at the stern or/and on at the bow. Some ships have ramps installed on the port side of the hull.
RoRo Size & Classes
RoRo ships are not categorized in any special classes and exists in broad variety of sizes, from small ferries to great pure car carriers of up to 8 000 CEU (Car Equivalent Unit).
RoRo Design & Types
General Design
As mentioned in the introduction the RoRos are specially designed to carry wheeled cargo that is “Rolled-on” through its built-in ramps. The machinery could be either medium speed engines or two-stroke engines depending on size and design. Design speed could everything from 8 knots up to 40+ for the high speed ferries.
RoRo Types
RORO vessels include ferries, cruiseferries, cargo ships, and barges and there are a number different variants accordingly.
PCC/PCTC PCC is an abbreviation of Pure Car Carrier. Today’s pure car carriers and their close cousins, the Pure Car/Truck Carrier (PCTC) are distinctive ships with a box-like superstructure running the entire length and breadth of the hull, fully enclosing and protecting the cargo. They typically have a stern ramp and a side ramp for dual loading of many thousands of vehicles, as well as extensive automatic fire control systems. The PCTC has liftable decks to increase vertical clearance as well as heavier decks for “high and heavy” cargo. A 6500 unit car ship with 12 decks can have three decks which can take cargo up to 150 short tons (136 t; 134 long tons) with liftable “panels” to increase clearance from 1.7 to 6.7 meters (5.6 to 22 ft) on some decks. Lifting decks to accommodate higher cargo reduces the total capacity.With the building of the Wallenius Wilhelmsen Logistics’s 8000 CEU car carrier Faust, out of Stockholm, in June 2007 the car carriers entered a new era called the LCTC (Large Car & Truck Carrier).
ROPAX
ConRO
The ConRo vessel is a hybrid between a RORO and a container ship. This type of vessel has a below-decks area used for vehicle storage while stacking containerized freight on the top decks. Examples of ConRo ships such as those in the fleet of Atlantic Container Line can carry a combination of 1,900 twenty-foot equivalent units (TEUs) of containers, up to 1,000 TEUs of heavy equipment, as well as project and oversized cargo on three decks and up to 2,000 automobiles on five decks. Separate internal ramp systems within the vessel segregate automobiles from other vehicles, mafi trailers and breakbulk cargo.
RoLo
A RoLo (roll-on lift-off) vessel is another hybrid vessel type with ramps serving vehicle decks but with other cargo decks accessible only by crane