This page explains the differences between the primary sub-types of battleship design/development, and between other types of ship that are often called battleships.
The 19th century was a time of rapid technological change in battleship design, but initial types were generically known as "Ironclads".
These ships were the first generation of well armoured ocean-going warships; the first battleships. They were either built from scratch with iron, or were conversions of wooden ships that had armour added to the sides for protection. The armament was carried on a gun deck that ran down the length of the hull in the same manner as previous wooden ships-of-the-line. Early ironclads were also referred to as "Armoured frigates" because the weight of the armour prevented them from carrying more than one gun deck. Nonetheless, these 'frigates' were all but invulnerable to even the largest multi-decked wooden line-of-battle ships.
As heavier and more powerful guns were developed the armour of the original Broadside Ironclads was no longer sufficient to protect them. To counter this the armament was concentrated in a battery amidships that was more heavily armoured. Also known as casemate ships, some central battery ships also allowed for some of the guns to have arcs of fire forward or aft. Carrying fewer, heavier guns in a concentrated area also allowed central-battery ships to be shorter and thus more manoeuvrable than broadside ironclads.
Turret ships mounted their main armament in armoured revolving platforms to enable a small number of the largest guns to fire in the widest possible arcs whilst still being protected. Barbettes were similar to turrets but the revolving platform was only protected on the sides by an armoured redoubt; there was no armoured roof.*
Pre-dreadnought is a term used retrospectively to describe the type of battleships constructed before HMS Dreadnought revolutionised battleship design. Because of advances in gun and ammunition technology giving better armour penetration, lighter guns were carried than in previous generations of battleship, as rate of fire was given more precedence. They had a mixed-calibre armament consisting usually of four twelve-inch guns in two turrets (one forward, one aft) and an assortment of lighter weapons in an amidships battery.
The battleship Dreadnought marked such an important change in battleship design that she rendered all previous battleships obsolete and all new battleships built to her standards were referred to as dreadnoughts. HMS Dreadnought incorporated many new ideas, but the most fundamental change was the adoption of a homogeneous-calibre of the largest possible size for the main armament. This came about in recognition of improvements in accuracy, allowing battleships to engage each other at greater ranges. Thus only guns of the largest (longest range) calibre were carried.
Super-dreadnought is not a clearly defined term, but is used to describe more modern dreadnoughts that were superior to their predecessors. They included the adoption of heavier calibre guns than the previously standard twelve-inch and the use of more advanced machinery to give higher speeds. The Queen Elizabeth class are often considered the first super-dreadnoughts because they combined all of the new technologies of the time to build a ship that was in many ways superior to all others. However, because many ships prior to the Queen Elizabeth class used some of their features - and some after did not - it is difficult to give and exact definition. Therefore, for the purposes of this site super-dreadnought has been used to refer to dreadnought battleships with greater calibre main armament than twelve-inch, so-as to maintain a consistent use of the term.
These were battleships that were markedly faster than their contemporaries. Advances in technology allowed for more powerful machinery to be fitted in smaller spaces. Fast battleships were able to reach or even exceed the speed of previous battlecruisers, so making the battlecruiser redundant.
Other Battleship-like Ships
The following types are used to classify some of the ships on this site which are often called battleships, although they are in actual fact not. Some of them are very similar to battleships, whereas others are really nothing like battleships at all.
The battlecruiser was very similar to the battleship except that it sacrificed armour for speed. The battlecruiser concept was that the ship would be fast enough to catch any other warship (such as cruisers) and then sink them using it's battleship sized armament from beyond enemy range. Were it to encounter a battleship of superior armament it would use it's higher speed to escape until other battleships could arrive in support. Whilst sound in theory, due to their heavy armament the temptation for their commanders was to deploy them as battleships, fighting other battleships (for which they were not intended), potentially with disastrous results. With the progress of technology and the advent of the fast battleship the type became more vulnerable and so fell out of favour.
Not a true battleship type, 'coastal battleships' were built by nations that could not afford to construct full sized ocean-going battleships. The concept of the coastal battleship was to place the largest guns and heaviest armour possible onto a ship of shallow draught so that the vessel would be able to out-fight anything else it would encounter in shallow coastal waters. In this way it could provide a local superiority to nations not able to contest the open ocean.
This term was coined to describe the German Deutschland class, built between the world wars. They were so-called because they carried a disproportionately heavy armament for their small displacement. Their main armament was far in excess of a cruiser's, although not on par with true battleships of the period. Their role was for commerce-raiding and they were really heavy cruisers. The German navy classified them as "panzerschiff" (armoured ship) rather than "schlachtschiff" (battleship) or "schwere kreuzer" (heavy cruiser).
This is not a 'proper' or commonly used term. Rather it is simply a term used on this site to describe the British Courageous class as accurately as possible. The Courageous class ships were often called battleships because of their large size and battleship calibre armament. However, the ships were only armoured like cruisers, not battleships. Nor did they have sufficient numbers of main armament for effective salvo firing and so could not fulfil the role of battle-cruiser either. The only role the ships were really fit for was that for which they were designed: coastal bombardment in support of an amphibious assault. Their size and armament calibre was comparable to a super-dreadnought, but the low number of guns carried, shallow draught, light armour and intended role was characteristic of a monitor.
* On later battleships the term "Barbette" came to mean the fixed armoured cylinder beneath the turret supporting its weight and protecting the ammunition hoists.