A ship is a large vessel that travels the world's oceans and other navigable waterways, carrying cargo or passengers, or in support of specialized missions, such as defense, research and fishing.

[16] For most of history, transport by ship – provided there is a feasible route – has generally been cheaper, safer and faster than making the same journey on land.

Cities such as Rome were totally reliant on the delivery by sailing and human powered (oars) ships of the large amounts of grain needed.

It has been estimated that it cost less for a sailing ship of the Roman Empire to carry grain the length of the Mediterranean than to move the same amount 15 miles by road.

A remarkable example of their shipbuilding skills was the Khufu ship, a vessel 143 feet (44 m) in length entombed at the foot of the Great Pyramid of Giza around 2500 BC and found intact in 1954.

The oldest discovered sea faring hulled boat is the Late Bronze Age Uluburun shipwreck off the coast of Turkey, dating back to 1300 BC.

This provided most of the ships used in the Age of Discovery, being able to carry sufficient stores for a long voyage and with a rig suited to the open ocean.

[13]: 29, passim The transition from clinker to carvel construction facilitated the use of artillery at sea since the internal framing of the hull could be made strong enough to accommodate the weight of guns.

As vessels became larger and the demand for ship-building timber affected the size of trees available, clinker construction became limited by the difficulty of finding large enough logs from which to cleave planks.

[j] Before the adoption of carvel construction, the increasing size of clinker-built vessels necessitated greater amounts of internal framing of their hulls for strength – something that somewhat lessened the conceptual change to the new technique.

Canal barges, towed by draft animals on an adjacent towpath, contended with the railway up to and past the early days of the Industrial Revolution.

These ships were 56 metres (184 ft) long and their construction required 2,800 oak trees and 40 kilometres (25 mi) of rope; they carried a crew of about 800 sailors and soldiers.

Higher boiler pressures of 60 pounds per square inch (410 kPa) powering compound engines, were introduced in 1865, making long-distance steam cargo vessels commercially viable on the route from England to China – even before the opening of the Suez Canal in 1869.

Even greater fuel efficiency was obtained with triple-expansion steam engines – but this had to wait for higher quality steel to be available to make boilers running at 125 pounds per square inch (860 kPa) in SS Aberdeen (1881).

Examples of freshwater waterways that are navigable in part by large vessels include the Danube, Mississippi, Rhine, Yangtze and Amazon Rivers, and the Great Lakes.

Similarly, the largest lakers are confined to the Upper Lakes (Superior, Michigan, Huron, Erie) because they are too large to use the Seaway locks, beginning at the Welland Canal that bypasses the Niagara River.

[61] Modern commercial vessels are typically powered by a single propeller driven by a diesel or, less usually, gas turbine engine.,[78] but until the mid-19th century they were predominantly square sail rigged.

[citation needed] Most commercial vessels such as container ships, have full hull-forms (higher Block coefficients) to maximize cargo capacity.

Changing siltation patterns may cause the sudden appearance of shoal waters, and often floating or sunken logs and trees (called snags) can endanger the hulls and propulsion of riverboats.

Modern warships are generally divided into seven main categories: aircraft carriers, cruisers, destroyers, frigates, corvettes, submarines and amphibious warfare ships.

Until the end of World War II the primary role of the diesel/electric submarine was anti-ship warfare, inserting and removing covert agents and military forces, and intelligence-gathering.

They are now generally used for recreation and competition, although experimental sail systems, such as the turbosails, rotorsails, and wingsails have been used on larger modern vessels for fuel savings.

Meanwhile, hydrogen and ammonia technologies are in development stages for long-haul applications, promising even more significant reductions in emissions and a step closer to achieving carbon-neutral shipping.

The first is usually an initial contract to build the ship, the details of which can vary widely based on relationships between the shipowners, operators, designers and the shipyard.

In Britain until Samuel Plimsoll's Merchant Shipping Act of 1876, ship-owners could load their vessels until their decks were almost awash, resulting in a dangerously unstable condition.

[108] Following the Exxon Valdez spill, the United States passed the Oil Pollution Act of 1990 (OPA-90), which included a stipulation that all tankers entering its waters be double-hulled by 2015.

Meinesz[111] believes that one of the worst cases of a single invasive species causing harm to an ecosystem can be attributed to a seemingly harmless planktonic organism .

Mnemiopsis leidyi, a species of comb jelly that inhabits estuaries from the United States to the Valdés peninsula in Argentina along the Atlantic coast, has caused notable damage in the Black Sea.

"[111] Now that the comb jellies have exhausted the zooplankton, including fish larvae, their numbers have fallen dramatically, yet they continue to maintain a stranglehold on the ecosystem.

Currently, the costs associated with removing asbestos, along with the potentially expensive insurance and health risks, have meant that ship-breaking in most developed countries is no longer economically viable.