Dry Cargo Ship

A cargo ship or freighter is any sort of ship or vessel that carries cargo, goods, and materials from one port to another. Thousands of cargo carriers ply the world’s seas and oceans each year; they handle the bulk of international trade. Cargo ships are usually specially designed for the task, often being equipped with cranes and other mechanisms to load and unload, and come in all sizes. Today, they are almost always built of welded steel, and with some exceptions generally have a life expectancy of 25 to 30 years before being scrapped.

Types

Cargo ships/freighters can be divided into five groups, according to the type of cargo they carry. These groups are:

• General Cargo Vessels
• Tankers
• Dry-bulk Carriers
• Multipurpose Vessels
• Reefer Ships

General Cargo Vessels carry packaged items like chemicals, foods, furniture, machinery, motor- and military vehicles, footwear, garments, etc.

Tankers carry petroleum products or other liquid cargo.

Dry Bulk Carriers carry coal, grain, ore and other similar products in loose form.

Multi-purpose Vessels, as the name suggests, carry different classes of cargo – e.g. liquid and general cargo – at the same time.

A Reefer (or Refrigerated) ship is specifically designed and used for shipping perishable commodities which require temperature-controlled, mostly fruits, meat, fish, vegetables, dairy productsand other foodstuffs.

Specialized types of cargo vessels include container ships and bulk carriers (technically tankers of all sizes are cargo ships, although they are routinely thought of as a separate category). Cargo ships fall into two further categories that reflect the services they offer to industry: liner and tramp services. Those on a fixed published schedule and fixed tariff rates are cargo liners. Tramp ships do not have fixed schedules. Users charter them to haul loads. Generally, the smaller shipping companies and private individuals operate tramp ships. Cargo liners run on fixed schedules published by the shipping companies. Each trip a liner takes is called a voyage. Liners mostly carry general cargo. However, some cargo liners may carry passengers also. A cargo liner that carries 12 or more passengers is called a combination or passenger-cum-cargo line.

 

Liquid Cargo Ship

They transport crude oil and petroleum products such as chute and diesel oil at a speed of 12-20 knots. Tankers are one-decked ships with the engine room and superstructure at the stern and a pump compartment often at the bow. The middle part of the tanker consists of a group of identical sections (called tanks) separated by cross walls in the hull. Hence the name of tankers. Each tank is equipped with a heating coil. You may wonder what the heating oil is for. In winter conditions liquid cargo, e.g. chute freezes and cannot be pumped out (and thus, unloaded). The coil gives off heat in the tank and keeps the chute fluid this way making pumping easier and faster. Ship design includes also the so-called “catwalk with the pipes” – this is a bridge which connects the superstructure (in the rear) with the forecastle (in the front). Thus, sailors do not have to walk along the deck to reach the forecastle machinery but can use this bridge. This is done as a safety measure rather than because of a whim. Let us explain – because tankers have quite a low freeboard, in a storm high waves may flow over the deck and threaten the crew. That’s why a “catwalk” is built high above the deck. Gigantic tankers do not have catwalks with the pipes but other “paths” instead.

With their fast rate of growth, tankers leave all other ships behind. In 1953, the first supertanker was launched under the name of “Tina Onasis”. She had a deadweight capacity of 46,080 t. Only twenty years later, the world has tankers reaching 500,000 t and above. A remarkable progress!

 

Passenger Ships

A passenger ship is a merchant ship whose primary function is to carry passengers. The category does not include cargo vessels which have accommodations for limited numbers of passengers, such as the ubiquitous twelve-passenger freighters once common on the seas in which the transport of passengers is secondary to the carriage of freight. The type does however include many classes of ships designed to transport substantial numbers of passengers as well as freight. Indeed, until recently virtually all ocean liners were able to transport mail, package freight and express, and other cargo in addition to passenger luggage, and were equipped with cargo holds and derricks, kingposts, or other cargo-handling gear for that purpose. Only in more recent ocean liners and in virtually all cruise ships has this cargo capacity been eliminated.

While typically passenger ships are part of the merchant marine, passenger ships have also been used as troopships and often are commissioned as naval ships when used as for that purpose.