Ships types and sizes guide

An overview of the types and sizes of dry cargo and tanker ships

The international dry cargo and tanker markets are immense and served by numerous ships of several types and various sizes. Some of the ships follow standard designs and can carry a variety of cargoes while others are more specialized and able to carry particular commodities which the standard vessels cannot. Since we have seen such a big variety of vessels in the OpenSea marketplace and since the vessel designs change rapidly from time to time, we decided to present a brief updated guide of the several types and sizes we may see around the world marketplace.

Dry Cargo Market

The dry cargo market is the one which experiences higher interest since the type of vessels are much more. The basic dry cargo vessels are broadly divided into the following main categories: General cargo vessels, Bulk Carriers, Short Sea (coaster) ships, Containerships and Specialised vessels while each of them consists of several subcategories mainly depending on their technical characteristics and/or sizes.

General cargo vessels: They were first mass-produced during the World War II when the 10,000 tons deadweight (dwt) “Liberty type” ships were very famous. They are built in such way that can carry general cargo, bagged/baled cargo as well as bulk cargo and, some of them, also containers. General cargo vessels are usually built in small sizes of about 5,000 to about 25,000-ton deadweight (dwt). Modern general cargo vessels are nearly always built with two decks and they are known as “tweendeckers”. In tweendeckers, each cargo hold can be split in two different sub-compartments: Between the main deck and the tweendeck, there is the tweendeck space (or upper cargo hold) while beneath the tweendeck there is the main cargo hold (or lower cargo hold). Tweendeckers face two main advantages against the single decker vessels: (a) they are equipped with more individual cargo compartments and thus they can carry several different cargoes, which can be kept separate from each other so as to avoid contamination and (b) they can accommodate higher tiers of bagged/baled cargoes with sharing their heavy weight in two different decks. At the same time, tweendecks can be retractable and fold against the sides of the hold so as to facilitate the load of bulk commodities into single holds. Modern general cargo ships are also equipped with special container fittings and are able to load containers. So nowadays the general cargo vessels are more accurately called “multi-purpose” vessels. General cargo vessels are equipped with gears with sufficient capacity (about 30-40 tons SWL) able to handle containers and other general cargoes.

Bulk Carriers

Bulk Carriers: As their name implies, these vessels mainly carry bulk cargoes (like coal, iron ore, grains, minerals etc) while it is not uncommon general cargoes (e.g. bagged cargoes and steels) to be loaded also in bulk carriers of smaller size. These vessels are single-deckers and they are not able to load containers. Their hatches have very large openings so as the vessel to be loaded/discharged quickly and the holds are unrestricted and free of obstacles. Due to the bulk nature of the cargo they load, the holds of these vessels have been constructed to be “self-trimming” to allow the easy and rapid stowage and trimming of the bulk cargoes. In contrast to the general cargo vessels which can load several different cargoes, cargo in bulk carriers is usually homogenous.

There are several different types of bulk carriers with the main distinction between each other being their size. Therefore, according to their size, we do have the below categories:

  • Mini Bulkers with deadweight of up to about 15,000 tons. They are mainly used in short sea trades however most vessels of this size are either general cargo ships or short sea specialized vessels rather than common bulk carriers.

  • Handysize bulkers have a deadweight from about 15,000 tons to about 39,000 tons and they are usually equipped with 5 cargo holds, while the smaller handies may contain 4 cargo holds as well. Except the conventional handysize, there are also those handysize bulkers of heavier construction which can load logs (along with other conventional cargoes). These vessels, known as “Loggers” and they are additionally equipped with lashing materials, stanchion sockets and stanchions alongside the bulwarks on ship’s deck so as the logs to be loaded and securely stowed. These stanchions may be permanent or collapsible. Also, handysize bulkers of between 20,000 and 30,000 MT deadweight designed to transit the St. Lawrence Seaway are commonly known as “Lakers”. The design of laker handies is: LOA of 70 meters, beam of about 21.5 meters, draft of 7.92 meters freshwater and airdraft (height above water level) not to exceed 35.6 meters.

  • Handymax bulkers have a deadweight from about 40,000 tons to about 50,000 tons and they are equipped with 5 cargo holds. However, they are mainly older designs and only a few vessels are nowadays built within this deadweight range.

  • Supramax bulkers, which have recently replaced handymaxes, have a deadweight from about 50,000 tons to about 60,000 tons. Like handymaxes, supramax bulkers also contain 5 cargo holds.

  • Ultramax is a new design which has been appeared recently in the market. These vessels, which are usually equipped with “eco main engine”, have a deadweight of about 62,000 – 65,000 dwt. Ultramax bulkers are considered as an upgrade of supramax bulkers and they are designed with five cargo holds.

  • Panamax bulkers are those who have a deadweight of between 70,000 and 80,000 tons, however there are still older panamaxes in the market (mainly built before 2000) with deadweight of between 60,000 and 70,000 tons. Panamaxes usually have 7 cargo holds and their name and dimension characteristics were established according to the maximum allowable dimensions (length and beam) for transiting the Panama Canal. Though, after the recent expansion of the Suez Canal, larger designs appeared so as to take advantage of the max deadweight at current Canal limitations. These vessels are known as post-panamax bulkers and their size varies from about 90,000 tons to about 110,000 tons deadweight.

  • Kamsarmax bulkers are slightly larger than panamaxes however other than that they are almost the same and they currently share the same sub-market with panamaxes. They have deadweight of between 80,000 and 85,000 tons (with their most common design being about 82,000 tons) and their LOA at 229 meters, which is slightly higher than the 224-225 meters LOA of Panamax, is the maximum permissible LOA to enter the port Kamsar in West Africa, which is one of the largest ports of bauxite in the world.

  • Capesize have a deadweight of between 160,000 tons and 210,000 tons. In the past, there were also smaller Capesizes known as mini-capes or babe-capes ranging between about 110,000 to about 160,000 tons and despite that there are still a few in the market, this is not a common design anymore. Capesizes usually have 9 cargo holds. Large Capesizes with a maximum beam of 47 meters are called Newcastlemax and they are the largest vessels which can enter the Newcastle port of Australia.

  • Ultra Large Ore Carriers: These are bulkers which are larger than capesizes and they are mainly used to load iron ore. The largest vessels in this category are the Valemax (or Chinamax) vessels which have a deadweight of as high as 400,000 tons.

The smaller bulk carriers, from mini-bulkers up to ultramaxes usually (but not always) are geared while the larger bulkers from panamax to chinamax are almost always gearless however there are also a few geared (mainly panamax and kamsarmax bulkers). Smaller bulkers can carry all the types of bulk cargoes as well as some general cargoes and usually used in shorter distances. Panamax and capesizes, on the other hand, are used to load mainly grains, coal, iron ore and, in less extent, other minerals. Large Ore Carriers and Valemax are used to carry iron ore.

In the below table, we summarise the main characteristics of a typical vessel for each category so as to see their similarities and differences in more detail.

Main characteristics of a typical vessel for each category

Containerships: These vessels are constructed to load containers only. Their holds are cellular, with vertical frames or guides where the containers are slotted. Container vessels range in size from as small as those with capacity of about 500 TEU and as large as those with capacity of about 22,000 TEU. Containerships can load both 20-foot and 40-foot containers and therefore each vessel should explain its maximum capacity for each of the two types of container. The smaller container vessels are used as feeder ships feeding the hinterland around major container terminals and may be geared while the largest containers are usually gearless and they can achieve speeds which exceed the 25 knots so as to be used in long voyages. Containerships operate in a much different manner than other dry vessels; they are usually chartered on period time charters from major liner companies who then offer fixed prices for each container to end clients. For this reason, OpenSea is not active in this specific market.

Short sea vessels: In short sea/coastal trades, small versions of deep sea general cargo vessels or mini bulkers are sometimes utilized. However, the short sea vessels, which usually have a deadweight of between 500 tons and 10,000 tons are constructed with special modifications peculiar to their trade. They are usually constructed with one hold served by an “open hatch” steel hatch cover while their holds are fully box-shaped so as to enable the loading of palletized cargo and increase their cargo intake. Modern box shaped short sea vessels used in grain trades are equipped with at least two moveable bulkheads enabling the vessel to load a full compartment comprising most of the ship’s capacity and a small compartment where the balance cargo can be slack without the need for bagging and strapping. Furthermore, recent short sea vessel designs allow also the superstructure and masts to be hydraulically lowered to enable the ship to sail beneath bridges and other overhead obstructions.

Specialized vessels

Specialized vessels: In this category, we can meet various type of vessels like the heavy-lift ships, the wood chip carriers, the livestock carriers, the refrigerated vessels and the Ro/Ro vessels.

  • Heavy-lift ships are similar with multi-purpose vessels however they are used to lift very heavy project cargoes which can reach up to 2,000 tons and which are impossible to be loaded by derricks or cranes in a conventional vessel.

  • The wood chip carriers are used for the carriage of wood chip products which are used in pulp mills. Their size is usually between 40,000 tons and 60,000 tons deadweight however it is usually measured in terms of hold capacity rather than deadweight. These vessels are equipped with cranes and also conveyor belt for the discharge of the cargo.

  • Livestock carriers are those used to carry animals and there are two main types: The sheep carriers and the cattle carriers. These vessels require special characteristics such as fodder storage, very good ventilation, extensive water supply, systems for animal waste disposal, specialized ramps and accommodation for those tending the animals. Livestock carriers (and especially the sheep carriers) are usually converted from another type of vessels but occasionally specialized ships are built (especially cattle carriers).

  • The refrigerated vessels are customary known as reefers and they are very specialized ships. They have two or more decks and their holds are insulated and they can keep the temperature in the holds at the cold level required by each cargo. They can achieve very high speed so as to reduce time and their gears can operate very fast so as the cargo not to be exposed during the load and discharge operations.

  • Ro/Ro vessels are suitable for cargo which can be driven on/off the ship such as cars, lorries and cargo on trailers. Ro/Ro are usually ferries and the two important measures indicating the size of Ro/Ro are the length of the marked parking lanes and the size of the entrance ramp.

Tanker Market

In tanker market, the situation is much more straightforward. The main categories that we meet are: the product tankers and the crude carriers while there are also the more specialized types which consist of the chemical tankers, the gas carriers and the asphalt/bitumen carriers.

Product tankers

Product tankers: When refined, crude oil separates into various oil products. The lightest of them are the clean products such as the gasoline, kerosene, gasoil while the heaviest are the dirty products known as fuel oils or residual oils. Product tankers are divided into many categories which are related to their size and whether they are suitable to load clean products or dirty products only. It is worth to note that clean product tankers can also load most of the grades of the dirty products (except probably of the heavy ones which require the highest temperature) but it does not exist the opposite with the dirty product tankers – which cannot load clean products. The difference between the clean and dirty product tankers are the following:

  • Clean product tankers require good cleaning before each loading and for this reason, their tanks are coated with special points which can also assist to reduce corrosion. Furthermore, clean product tankers are characterized of higher and more advanced segregation systems and they can load separate grades of cargo without risk of contamination.

  • Dirty product tankers, on the other hand, are not equipped with special coating and they do not accommodate complex segregation systems, however they are usually equipped with heating coils so as to be able to pump the high-density grades of fuel oil.

Product tankers vary in size from general purpose tankers up to about 160,000 tons deadweight.

Crude Carriers: Crude Oil cargoes are usually homogenous and even when different grades of crude oil are carried on board the same ship there is no risk of contamination since the oil will be refined before its sale to the end-users. Therefore, crude carriers are used for the carriage of the crude oil from oil producing countries to the refineries and their size ranges from about 50,000 MT deadweight to more than 500,000 MT deadweight which is the size of modern ULCC. These vessels can load one or up to two grades and their pumping and pipeline systems are relatively simple as opposed to the product tankers.

In terms of size, product tankers and crude carriers are divided into the following main categories:

  • General Purpose tankers: They are used to load refined products and their size is between 10,000 MT and 25,000 MT deadweight.

  • Handysize tankers: Used to load refined products and their deadweight is between 25,000 MT and 40,000 MT

  • MR (Medium Range) tankers: Used to load refined products and their size is between 40,000 MT and 55,000 MT deadweight

  • LR1 (Long Range 1) tankers: They are used to load both refined products and crude oil. The ones suitable for dirty products or crude oil are used to be called panamax tankers. LR1 and panamax tankers have a deadweight of between 55,000 MT and 80,000 MT.

  • LR2 (Long Range 2) tankers: They are suitable for carrying both refined products and crude oil while their size is between 80,000 MT deadweight and 160,000 MT deadweight. It is worth to note that the LR2 vessels suitable to load crude oil are usually called Aframax tankers (from 80,000 MT to 120,000 MT deadweight) and Suezmax tankers (from 120,000 MT to 160,000 MT) instead.

  • Very Large Crude Carriers (VLCC) and Ultra Large Crude Carriers (ULCC) are used to carry crude oil only and their size can reach up to about 320,000 MT for the VLCC and up to about 550,000 MT for the ULCC.

Chemical tankers: They are also called parcel tankers and they are usually of small size from about 5,000 tons dwt to about 25,000 dwt while there are also a few chemical tankers up to about 50,000 tons deadweight. Chemical tankers are mainly used in two trades: For the carriage of oils which are extremely hazardous (IMO I) and the carriage of edible/vegetable oils as well as very clean oil products (IMO II / IMO III). In order to carry hazardous cargoes with safety these vessels need to be equipped with very high standards a few of which are the following:

  • — The tanks are coated with high-grade materials such as stainless steel, epoxy resin and zinc silicate being the most popular. These coatings are cleaned easier and also prevent the chemical cargoes to react with the vessel’s hull and damaging the ship or the cargo.

  • — Each tank has its own deepwell pump and pipeline system, therefore, the cargo of each tank is loaded and discharged separately. This way various different grades can be loaded separately while there is absolutely no risk of contamination since there is full segregation.

Gas Carriers: They are highly specialized form of tanker. The two types of gas carriers are known as LNG (Liquefied Natural Gas) and LPG (Liquefied Petroleum Gas). The LNG is the methane product and it is carried in insulated tanks in minus 162 degrees Celsius at atmospheric pressure so as to maintain in liquid condition. The LPG Carriers are used to load mainly propane and butane while they are also used for the carriage of chemical gas and ammonia and there are two different types of LPG Carriers. The fully pressurized vessels which load and maintain the cargo in a high pressure of 10-12 bars and the refrigerated which cool the cargo at temperatures of up to minus 50 degrees Celsius. The size of the Gas Carriers is usually declared basis their cubic capacity in CBM and there are LPG Carriers from small LPGs of about 500 cbm to VLGC of about 85,000 cbm while the LNG Carriers are as large as about 265,000 cbm. Specifically, the Q-Flex design which is about 210,000 - 217,000 cbm and the Q-Max with a capacity of about 261,700-266,000 cbm that make up the Qatari Q-Class offer the largest available capacities and they were accounted for about 18% of the total LNG carrying capacity at the end of 2016.

Asphalt Carriers: Small tankers suitable to carry asphalt/ bitumen most of which not exceed the 7,500 dwt while there are also a few larger bitumen tankers and recently some yards in China are marketing newbuilding designs of up to about 20,000 dwt. The main characteristics of these tankers are that they can achieve and maintain high temperatures of up to about 200 degrees Celsius. These vessels usually are not equipped with Inert Gas system and COW and they cannot load other oil cargoes except, probably, of a few dirty products which do not have risk for contamination and do not require cleaning.

The OpenSea marketplace can accommodate almost all above mentioned types of ships and as soon as you place your ship or your cargo, our smart matching algorithms will find the best candidates instantly. This way, our users are receiving only firm offers which are suitable for their inquiries and save their precious time which can be spent on negotiations rather than on processing bulk email searches and reading irrelevant emails.

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