Merchant ship

• 1. Introduction

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  A merchant ship can be a 20-foot inflatable dive boat off the coast of Hawaii. It can also be a 1,000-foot oil tanker easing into a major port. The same category stretches to casino vessels carrying 5,000 passengers and more down the Mississippi River, to tugboats working New York Harbor, and even to passenger-carrying submarines in the Caribbean. What ties these wildly different watercraft together is not size or shape. It is purpose. A merchant ship, also called a merchant vessel, a trading vessel, or a merchantman, exists to move cargo or carry passengers for hire. That single word, hire, sets it apart from a pleasure craft built for personal recreation and from a naval ship built for war. So how does one word organize a fleet that spans inflatable boats and floating giants? Why do so many of these vessels fly a flag from a country their owners have never lived in? And how does a ship grow so large that running it at full capacity becomes impossible? The answers reach from the Greek merchant marine to the rusting hull of the largest vessel ever built.

• 2. Flags Of Convenience

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  Liberia and Panama appear on the sterns of ships whose owners live nowhere near either country. This is the practice known as a flag of convenience, where a vessel registers under a nation other than the home of its owners. The draw is legal. Both Liberia and Panama maintain maritime laws more favorable to shipowners than those of other countries. Registration becomes a business decision rather than a statement of nationality. The Greek merchant marine stands as the largest in the world, a measure of national shipping reach rather than registration paperwork. The Greek fleet accounts for some 16 per cent of the world's tonnage. That share makes it currently the largest single international merchant fleet in the world, though the source is careful to note it is not the largest in history. Tonnage, then, is one yardstick of dominance, and Greece holds the top of it today. Wartime rewrites what a merchant ship is for. During wars, merchant vessels may be pressed into service as auxiliaries to the navies of their respective countries. They are called upon to deliver military personnel and materiel, turning trade ships into instruments of supply. The same hull that carried grain in peace can carry soldiers in conflict.

• 3. Naming The Fleet

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  CS, LNG, RMS, SS. A merchant ship announces what it is before you ever read its name, through a prefix bolted to the front. CS marks a cable ship or cable layer. LNG signals a gas carrier moving liquefied natural gas, while LPG marks one carrying liquefied petroleum gas. The alphabet here is a working vocabulary. MFV stands for Motor Fishing Vessel, and MS for Motorship. MSV labels a Motor Stand-by Vessel, MT a Motor Tanker or Motor Tug Boat, and MV a Motor or Merchant Vessel. MY designates a Motor Yacht. NS reaches into rarer territory as the prefix for a Nuclear Ship. RMS belongs to a Royal Mail Ship, and RRS to a Royal Research Ship. RV marks a Research Vessel, SS a Steam Ship, and SV a Sailing Vessel, the last of which can be further sub-coded by type. Language sorts the fleet in other ways too. In English, the term Merchant Navy without further clarification refers to the British Merchant Navy. The United States merchant fleet carries a different name, the United States Merchant Marine. The United States Coast Guard adds its own definition, calling a commercial vessel any boat or ship engaged in commercial trade or carrying passengers for hire. The same water holds a Merchant Navy and a Merchant Marine, separated by a border and a word.

• 4. Sorting The Cargo

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  The UNCTAD review of maritime transport draws the official boundaries between ship types. It sorts vessels into oil tankers, bulk and combination carriers, general cargo ships, container ships, and a catch-all called other ships. That final group gathers liquefied petroleum gas carriers, liquefied natural gas carriers, parcel or chemical tankers, specialized tankers, reefers, offshore supply vessels, tugs, dredgers, cruise ships, ferries, and other non-cargo craft. General cargo ships themselves include multi-purpose and project vessels along with Roll-on, roll-off cargo ships. A cargo ship, also called a freighter, is the workhorse beneath all that classification. It carries cargo, goods, and materials from one port to another, and thousands of them ply the world's seas and oceans each year. Together they handle the bulk of international trade. These ships are usually built for the task, often fitted with cranes and other mechanisms to load and unload, and they come in all sizes. Bulk carriers reveal themselves by their decks. Large box-like hatches sit on top, designed to slide outboard or fold fore-and-aft so cargo can be loaded or discharged. Inside go iron ore, bauxite, coal, cement, grain, and similar loads. Their dimensions are often dictated by the ports and sea routes they serve, and by the maximum width of the Panama Canal. Most lakes are too small to hold them, yet a large fleet of lake freighters has worked the Great Lakes and St. Lawrence Seaway of North America for over a century. Containerization built its own class of ship. A container ship carries its cargo in standardized containers, a technique that made these vessels a common means of commercial intermodal freight transport. The standard box is what lets a load move from ship to truck to rail without being unpacked.

• 5. The Limits Of Size

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  Oil, ammonia, chlorine, styrene monomer, fresh water, and even wine all travel inside tankers. A tanker is a ship designed to carry liquids in bulk, and its cargo list runs from hydrocarbons like oil, LPG, and LNG to industrial chemicals and ordinary drinking water. Because each product demands different handling and transport, builders developed special types, including chemical tankers, oil tankers, and gas carriers. Size in this class spans an enormous range, from several hundred tons serving small harbours and coastal settlements to several hundred thousand tons built for long-range haulage. Supertankers were born from a single route, the long haul of oil around the Horn of Africa from the Middle East. At the extreme end stood the FSO Knock Nevis, the largest vessel in the world, a ULCC supertanker once known as Jahre Viking and earlier as Seawise Giant. Its scale defies easy picture, with a deadweight of 565,000 metric tons and a length of about 458 metres. Yet that bigness carried a flaw. Operating such ships at full cargo capacity proved nearly impossible, which made them very unprofitable, and the production of supertankers has currently ceased. The same lesson repeats in the ships that followed. Today's largest oil tankers by gross tonnage are the TI Europe, TI Asia, and TI Oceania, described as the largest sailing vessels today. Even with a deadweight of 441,585 metric tons, sailing as VLCCs most of the time, they do not use more than 70 per cent of their total capacity. Apart from pipeline transport, tankers remain the only method for moving large quantities of oil. That dependence carries a cost when something goes wrong. Tankers have caused large environmental disasters when sinking close to coastal regions, spilling oil into the water. The source points to the Erika, the Exxon Valdez, and the Prestige as examples of tankers involved in oil spills.

• 6. Coasts And Passengers

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  Shallow hulls let coasters sail over reefs and other submerged navigation hazards that would tear open a deeper ship. Coastal trading vessels are the smaller ships that carry any category of cargo along coastal routes rather than crossing oceans. They run trade between locations on the same island or continent. The contrast is built into the hull itself, because vessels meant for blue-water trade usually have much deeper hulls for better seakeeping. Geometry decides where a ship can safely go. Passenger ships answer a different demand, carrying people rather than freight as their primary function. The category leaves out cargo vessels that merely have accommodations for a few travellers, like the formerly ubiquitous twelve-passenger freighters where passengers came second to cargo. It does include many classes built to carry substantial numbers of passengers alongside freight. Until recently, virtually all ocean liners could carry mail, package freight, express, and other cargo on top of passenger luggage, equipped with cargo holds and derricks, kingposts, or other cargo-handling gear. The line between passenger and cargo ship is thinner than it looks. Cars, lorries, and even railroad cars roll directly onto some of these vessels. Modern cruiseferries have car decks for lorries as well as the passengers' own cars. A ferry is a boat or ship carrying passengers and sometimes their vehicles, and ferries also move freight in lorries and unpowered freight containers. In the case of a train ferry, the cargo is the railroad cars themselves, driven aboard on rails. Only in more recent ocean liners and in virtually all cruise ships has that cargo capacity finally been stripped away, leaving the passenger alone at the center of the design.