A ship, like a boat, is a vehicle designed for passage or transportation across water. It is usually large enough to carry its own boats, such as lifeboats, dinghies, or runabouts. A rule of thumb saying (though it doesn't always apply) is "a boat can fit on a ship, but a ship can't fit on a boat". The exact size at which a ship becomes a boat is often defined by local law and regulation. Submarines are always called boats.

Nautical means related to ships, particularly customs and practices at sea.

In nautical history terms, a ship specifically signifies a three-masted sailing vessel with square sails on all three masts.

Table of contents
1 Types of ships in use
2 Historical types of ships
3 How ships are measured
4 Propulsion
5 Ships in the Bible
6 See also

Types of ships in use

Historical types of ships

How ships are measured

Ships are measured in terms of overall length, length along the waterline, beam (breadth) and tonnage. There are a number of different tonnage definitions, the majority of which are measures of volume rather than displacement. Displacement is most frequently applied to naval vessels and is equal to the actual weight of a ship under specific conditions. "Light ship" tonnage is the actual weight of the ship with no fuel, no persons, no cargo, no water on board, just as it first entered the water. The term "displacement" is used because of the basic physical law, discovered by Archimedes, that the weight of a floating object is exactly that of the weight of the water that would otherwise be in the "hole in the water" created by the ship.

In England, up until the end of the 19th century, ships could be loaded until their decks were almost awash, resulting in a dangerously unstable condition. Additionally, anyone who signed onto the ship for a voyage and, upon realizing that there was danger, chose to leave the ship, could be jailed.

Samuel Plimsoll, a member of Parliament, realized the problem and engaged some engineers to derive a fairly simple formula to determine the position of a line on the side of any specific ship's hull which, when it reached the surface of the water during loading of cargo, meant the ship was as deeply laden as it could safely be. To this day, that mark exists on ships' sides, is called the "Plimsoll Mark", and is a circle with a horizontal line through the center. Because different types of water, (summer, fresh, tropical fresh, winter north Atlantic) have different densities, it became required that a group of lines forward of the Plimsoll Mark be installed to indicate the safe depth (or freeboard above the surface) to which a specific ship could be loaded in water of various densities. That is the "ladder" of lines seen forward of the Plimsoll Mark to this day.

The front of a ship is called the bow, and the rear is the stern. The side of the ship which is on the right when the observer is facing forward is called starboard; the left side is called port. (An easy way to remember port and starboard is that left and port both have four letters.) Different levels of a ship are called decks.

"Walls" in a ship are called "bulkheads". Many are structural members, as well. They serve to maintain stability, prevent water from flooding the entire ship in the event of a breach of the hull, and contain fire. Many are fitted with watertight doors which, in the case of certain types of ships, may be remotely closed.


A few early ships were powered by man, such as the Greek trireme, but most ships were sailing vessels powered by the wind.

The first steamship was the 45-foot Comet of 1812, and steam propulsion progressed considerably over the rest of the 19th century. Notable developments included the condenser, which reduced the requirement for fresh water, and the multiple expansion engine, which improved efficiency. Further efficiencies resulted from the development of the marine steam turbine by Sir Charles Parsons, who demonstrated it on the 100-foot Turbinia at the Spithead Naval Review in 1897. This facilitated a generation of high-speed liners in the first half of the 20th century.

The marine diesel was first used around 1920. It soon offered even greater efficiency than the steam turbine but, for many years, an inferior power to space ratio. Most ships built since around 1960 have been diesel powered, or motor ships, one exception being the Queen Elizabeth 2 of 1968, which was fitted with steam turbines (although she was subsequently converted to diesel as a cost saving measure).

A few ships have been powered by nuclear reactors, but this form of propulsion has caused concerns about safety and has only been popular in large aircraft carriers and in submarines, where the ability to run submerged for long periods has obvious benefits.

Ships in the Bible

Early used in foreign commerce by the Phoenicians (Gen. 49:13). Moses (Deut. 28:68) and Job (9:26) make reference to them, and Balaam speaks of the "ships of Chittim" (Num. 24:24). Solomon constructed a navy at Ezion-geber by the assistance of Hiram's sailors (1 Kings 9:26-28; 2 Chr. 8:18). Afterwards, Jehoshaphat sought to provide himself with a navy at the same port, but his ships appear to have been wrecked before they set sail (1 Kings 22:48, 49; 2 Chr. 20:35-37).

In Jesus' time fishermen's boats on the Sea of Galilee were called "ships." Much may be learned regarding the construction of ancient merchant ships and navigation from the record in Acts 27, 28.

From Easton's Bible Dictionary (1897)

See also

I must go down to the sea again, to the lonely sea and the sky,
And all I ask is a tall ship, and a star to steer her by...
-John Masefield

copyright 2004