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. Only the coming of railways in the middle of the 19th century and the growth of commercial aviation in the second half of the 20th century have changed this principle. This applied equally to sea crossings, coastal voyages and use of rivers and lakes.

Examples of the consequences of this include the large grain trade in the Mediterranean during the classical period. 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. Rome consumed about 150,000 tons of Egyptian grain each year over the first three centuries AD.

Until recently, it was generally the case that a ship represented the most advanced representation of the technology that any society could achieve.
The earliest attestations of ships in maritime transport in Mesopotamia are model ships, which date back to the 4th millennium BC. In archaic texts in Uruk, Sumer, the ideogram for "ship" is attested, but in the inscriptions of the kings of Lagash, ships were first mentioned in connection to maritime trade and naval warfare at around 2500–2350 BCE.

Austronesian peoples originated in what is now Taiwan. From here, they took part in the Austronesian Expansion. Their distinctive maritime technology was integral to this movement and included catamarans and outriggers. It has been suggested that they had sails some time before 2000 BCE. Their crab claw sails enabled them to sail for vast distances in open ocean. From Taiwan, they rapidly colonized the islands of Maritime Southeast Asia, then sailed further onwards to Micronesia, Island Melanesia, Polynesia, and Madagascar, eventually colonizing a territory spanning half the globe.

Austronesian sails were made from woven leaves, usually from pandan plants. These were complemented by paddlers, who usually positioned themselves on platforms on the outriggers in the larger boats. Austronesian ships ranged in complexity from simple dugout canoes with outriggers or lashed together to large edge-pegged plank-built boats built around a keel made from a dugout canoe. Their designs were unique, evolving from ancient rafts to the characteristic double-hulled, single-outrigger, and double-outrigger designs of Austronesian ships.

In the 2nd century AD, people from the Indonesian archipelago already …

Read more on Wikipedia

Because ships are constructed using the principles of naval architecture that require same structural components, their classification is based on their function such as that suggested by Paulet and Presles, which requires modification of the components. The categories accepted in general by naval architects are:
• High-speed craft – Multihulls including wave piercers, small-waterplane-area twin hull (SWATH), surface effect ships and hovercraft, hydrofoil, wing in ground effect craft (WIG).
• Off shore oil vessels – Platform supply vessels, pipe layers, accommodation and crane barges, non and semi-submersible drilling rigs, drill ships, production platforms, floating production storage and offloading units.
• Fishing vessels
• Harbour work craft
• Dry cargo ships – tramp freighters, bulk carriers, cargo liners, container vessels, barge carriers, Ro-Ro ships, refrigerated cargo ships, timber carriers, livestock carriers & light vehicle carriers.
• Liquid cargo ships – tankers, oil tankers, liquefied gas carriers, LNG carriers, chemical carriers.
• Passenger ships
• Sail training and sailing ships
• Galleys – biremes, triremes and quinquiremes
• Recreational boats and craft – rowed, masted and motorised craft
• Special-purpose vessels – weather and research vessels, deep sea survey vessels, and icebreakers.
• Submarines – watercraft capable of independent operation underwater.
• Naval ships
• Hospital ships
Some of these are discussed in the following sections.
Freshwater shipping may occur on lakes, rivers and canals. Ships designed for those body of waters may be specially adapted to the widths and depths of specific waterways. 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.
Lake freighters, also called lakers, are cargo vessels that ply the Great Lakes. The most well-known is SS Edmund Fitzgerald, the latest major vessel to be wrecked on the Lakes. These vessels are traditionally called boats, not ships. Visiting ocean-going vessels are called "salties". Because of their additional beam, very large salties are never seen inland of the Saint La…

Read more on Wikipedia

Some components exist in vessels of any size and purpose. Every vessel has a hull of sorts. Every vessel has some sort of propulsion, whether it's a pole, an ox, or a nuclear reactor. Most vessels have some sort of steering system. Other characteristics are common, but not as universal, such as compartments, holds, a superstructure, and equipment such as anchors and winches.
For a ship to float, its weight must be less than that of the water displaced by the ship's hull. There are many types of hulls, from logs lashed together to form a raft to the advanced hulls of America's Cup sailboats. A vessel may have a single hull (called a monohull design), two in the case of catamarans, or three in the case of trimarans. Vessels with more than three hulls are rare, but some experiments have been conducted with designs such as pentamarans. Multiple hulls are generally parallel to each other and connected by rigid arms.

Hulls have several elements. The bow is the foremost part of the hull. Many ships feature a bulbous bow. The keel is at the very bottom of the hull, extending the entire length of the ship. The rear part of the hull is known as the stern, and many hulls have a flat back known as a transom. Common hull appendages include propellers for propulsion, rudders for steering, and stabilizers to quell a ship's rolling motion. Other hull features can be related to the vessel's work, such as fishing gear and sonar domes.

Hulls are subject to various hydrostatic and hydrodynamic constraints. The key hydrostatic constraint is that it must be able to support the entire weight of the boat, and maintain stability even with often unevenly distributed weight. Hydrodynamic constraints include the ability to withstand shock waves, weather collisions and groundings.

Older ships and pleasure craft often have or had wooden hulls. Steel is used for most commercial vessels. Aluminium is frequently used for fast vessels, and composite materials are often found in sailboats and pleasure craft. Some ships have been made with concrete hulls.
Propulsion systems for ships fall into three categories: human propulsion, sailing, and mechanical propulsion. Human propulsion includes rowing, which was used even on large galleys. Propulsion by sail generally consists of a sail hoisted on an erect mast, supported by stays and spars and controlled by ropes. Sail systems were the dominant form of propulsion until the 19th century. 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.

Mechanical

Read more on Wikipedia