Portcities Southampton
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Common purpose different means

Diversity and individuality

Ships and boats show an enormous diversity.  All have in common an ability to float, a facility to be steered in the desired direction and some form of propulsive power.  But the means of achieving these purposes differs greatly from vessel to vessel.  The Viking longship and the gas tanker float, are steered and propelled, but could not be more different in their method, form, size and construction.

Even ships designed to do the same job, at the same period, may be very different in form.  Ships are not usually built in a series production process, unlike almost all other vehicles.  They are built individually, or sometimes in small batches, by many different ship yards.  Their design is influenced by many factors, including most importantly what they have to carry or do and where.  But also important are the ideas of the owner, the designer and the shipbuilder.  The factors which influence the form a ship takes are explored in ‘Why are ships so diverse?’

Ships or boats?

Let us first sort out an important difference, that between boats and ships.  The difference is essentially one of size, with ships usually being larger than boats.  The strict definition is that a boat is a vessel with only one deck, and a ship has more than one.  However, those connected with the sea have often used the term ‘boat’ rather colloquially to refer to a particular type of ships or a company’s fleet.  Thus they might say ‘He serves in coal boats’, or ‘I shipped on Cunard boats’.  However, woe betide the landsman who uses ‘boat’ wrongly!  Another odd usage is for submarines, which do have more than one deck, but are always referred to as ‘boats

Changes over time

Like any form of technology, ships evolve over time.  This results from developments in building techniques, such as the use of planks rather than hollowed out logs, or the replacement of wood with iron and later steel.  One of the greatest changes was the introduction of the steam engine in the 19th century which made ships independent of wind and tide.  In more recent times, containerisation has had a momentous effect on shipping, on seafarers and on ports.  All these changes and many more have resulted in a plethora of ship types over the ages.

Because the changes over time are so great, this website examines ship types in four ‘ages’, from ancient times to the middle ages, the great age of sail from the middle of the 15th century until the coming of steam in the 19th century, the steam age from about 1800 to 1950 and ships of today.  Unlike the ships, these divisions are not watertight.  The early types of boat described in ‘Ships from ancient times’ have in some areas persisted until recent times.  Modern sail training ships are rigged in just the same way as vessels discussed in ‘Ships in the great age of sail’.  A modern general cargo ship does the same job, albeit more efficiently, as the steam tramp featured in ‘Ships of the steam age’.  However, a particular type of ship will usually be found in the section covering the ‘age’ in which it developed.  For instance, the steam tramp in ‘Ships of the steam age’, a car carrier in ‘Ships of today’.