The fictional universe of The Culture, created by Iain M Banks, contains a wide range of space vessels types, most of which contain sentient Minds and which play a key role in the society of the Culture and in the plots of the novels set within it. Most of the lengthy names of ship classifications are shortened to three-letter acronyms (e.g. GSV).
Beyond the capabilities of a full-scale Mind, Culture ships usually share a number of similar technological capabilities such as:
A Systems Vehicle represents the full spectrum of the Culture's capabilities, since it can access all of the information known by the Culture and can make anything that the Culture can make. Systems Vehicles are enormously magnified von Neumann probes, as their essential components are engines, multi-purpose factories and Minds (advanced artificial intelligences). With these capabilities a Systems Vehicle can function as anything its Mind(s) and the Culture chooses. The most common and most visible functions are:
When the Culture got embroiled in its first major war (early in the series of Culture stories), at first it had no specialist warships and had to use Systems Vehicles (mainly General Systems Vehicles, the largest class) and General Contact Units for combat. This was a waste of the resources and capabilities invested in Systems Vehicles - although their size and manufacturing capacity makes them formidable and sometimes devastating opponents, the cost of losing such a vessel was considered too high to risk it in general conflicts.
General Systems Vehicles (GSVs) are the Culture's largest type of ship, ranging between 25km and 200km in each dimension (including the fields protecting them and forming the exterior of their life-support system). GSVs which provide accommodation for biological members of the Culture generally have populations in the millions or even billions, and can be considered worlds in their own right. However, they are also, with some lead time, able to transform into massive factories or warships. In one of the Culture novels (Excession), a GSV unloads its organic population and transforms itself into a very fast-moving shipyard / mothership, effectively deciding the outcome of the main plot thread.
GSVs are so complex and so vital to the Culture that they are described as generally being controlled by three Minds. So far (2008) Banks generally assumes that a GSV's three Minds agree on major issues, but has also explored the possibility and consequences of major disagreements, which can result in the losing Mind(s) being forced off the ship and the winning Mind(s) taking full control.
Classes of GSV are usually named after the largest planetary geological/geographical features. Some of the known classes of GSV are (in decreasing order of size and capability):
Medium Systems Vehicles (MSVs) are similar to GSVs but smaller. As the size of a typical GSVs tended to increase over time in the Culture's evolution, some ships which were previously designated as GSVs were "demoted" to MSVs. But a demoted ship with a good track record typically retains its influence (for example the Not Invented Here in Excession).
Some of the known classes of MSV are:
Limited Systems Vehicles (LSVs) are similar to MSVs but smaller. As ship sizes increased over time, some ships which were previously designated as MSVs were "demoted" to LSVs - though a demoted ship with a good track record will typically retain its influence.
Some of the known classes of LSV are:
General Contact Vehicles (GCVs) are ambassador/scout ships, presumed to be a Contact-only Systems Vehicle, or a larger version of a General Contact Unit if one follows the usual naming conventions in the Culture. However, there was only one very limited description in Excession and a passing mention in Matter. Known classes are:
General Contact Units (GCUs) are fast, independent, general-purpose vessels which the Culture's Contact group uses for diplomacy, espionage, subversion and sabotage. The Culture has no policy of non-interference (such as the Prime Directive in the Star Trek series) and, to the contrary, often tries to change the course of civilisations of whose behaviour it disapproves or which it considers in need of advancement.
GCUs typically have a crew of Contact members, numbering around 300. GCUs' Minds are sometimes somewhat eccentric (not to be confused with Eccentric - see below).
In the early stages of a conflict, GCUs are able to act as warships until GOU and ROU types become available. Because the Culture is more advanced than most other spacefaring civilisations, GCUs are usually very effective in combat. However during the Idiran-Culture War the Culture starts to produce GOUs and ROUs which are optimised for combat.
Classes of GCU are usually named after geographical features, some of the known classes are:
GCUs are much smaller than GSVs (though small only by comparison), and are routinely carried within GSVs on long journeys.
One of the best known GCUs in Banks' stories is Grey Area, known widely by the other Minds as Meatfucker because it breaches the taboo against looking inside the minds of living creatures.
Limited Contact Units (LCUs) Mentioned only in passing in Excession, these are presumed to be smaller or earlier versions of GCUs. Known classes are:
The Culture started producing specialist combat ships during its only full-scale war, against the Idirans. After that war it continued producing increasingly advanced Offensive Units but at a much slower rate. In Excession, a single Offensive Unit of the latest type successfully engages in combat against a fleet of Offensive Units left over from the Idiran-Culture war.
Offensive Units' Minds are usually pugnacious and macho (particularly by the Culture's normal standards), and most non-combat ships regard Offensive Units with a mixture of respect and unease verging on mild contempt.
General Offensive Units (GOUs) are the main warships of the culture, the epitome of the Culture's technology as applied (reluctantly) to warfare. The only type of Culture unit comparable in firepower to a GOU would be a GSV self-modified for military use (see for example GSV Lasting Damage).
Known classes are:
Rapid Offensive Units' (ROUs) consist of little more than engines, weapons and the ship's Mind. While some ROUs are crewed, the crew complement on such vessels is much smaller than those of the more general purpose ships of the Culture, such as General Contact Units and General Systems Vehicles. ROUs and their demilitarised versions, Very Fast Pickets, are the Culture's fastest ships and have so far been described as having been outrun only once, by a GSV that self-optimised for speed (in the novel Excession).
ROUs frequently store a copy of their Mind state with another ship before going into action, and these backups are frequently installed in new ships if the ROU does not survive. This is in part a reward for the self sacrifice of the ships, and a motivation for bravery in combat. It is also a tacit admission by the Culture that it prefers peace over war - the number of warships required is small, and the creation of new warship Minds is also undesirable over the birth of peace-loving Minds.
Known classes are:
Limited Offensive Units (LOUs) are a smaller type of warship along the line of GOU's.
Known classes are:
A few other types of ships appear in Banks' Culture stories:
During peaceful times some ROUs have most or all of their weapons systems removed, and are known as demilitarized Rapid Offensive Units ((d)ROUs). Some 'surplus' ROUs are not demilitarized but are stored at various Culture-controlled locations, where they lie in a suspended state until they are needed again. Classes are the same as ROUs.
A euphemism for a demilitarised ROU, which was in fashion at the time of Look to Windward. It is first mentioned in Use of Weapons and also Excession. Classes are the same as ROUs/(d)ROUs.
A demilitarised GOU.
Superlifters are relatively small Culture ships with large and powerful engines. Superlifters described as being 90% engine are mentioned in Excession, faster even than a Rapid Offensive Unit (or Very Fast Picket) over short distances. Superlifters were never militarised as a class, though they are described in Matter as often having served on the frontlines of the Idiran War, including being equipped with weapons.
They are mainly used as high-speed shuttles between Culture Systems Vehicles (when it is inconvenient for the larger ships to decelerate), as movers of raw materials for building Orbitals or other space habitats, and for providing other Culture ships with a 'boost' to aid in rapid deceleration or acceleration.
Known classes are:
Since Culture ships are always commanded by a Mind they are always beings in their own right. In some Culture stories ships are the major characters, and their relationships are central to the plot. Ships or groups of ships may belong to differing factions within or without the culture, which compete for influence.
Some ships drop out of the Culture proper without joining any other civilisation or splinter group, either due to mental 'instability' (though only compared with the very reasoned rationality of the other Culture Minds) or disagreement with the Culture society as such. However, most of these ships maintain contact with the Culture and act as members of the Culture when they consider it appropriate.
Some of these ships may use their status as Eccentrics as a cover for Special Circumstances (a sub-section of Contact that handles espionage, sabotage and responses to major emergencies) , or simply to conceal their political allegiances within the Culture (Excession provides examples of both).
Sometimes a ship decides that it wishes to have a sabbatical from its duties in the Culture, especially after a particularly harrowing or ethically problematic situation (or maybe simply after being fed up with the Culture for a time). This sabbatical may be for some months, years, or longer.
Sabbaticalers are usually still considered Culture ships, and may or may not be Eccentric.
Occasionally ships conclude that the Culture is too cautious or conservative (or even too warlike, as in the Idiran-Culture War, when a minority section of the Culture voted against the use of force and split off, forming the Peace faction) and join groups like the Zetetic Elench or other offshoots of the Culture, or form their own group. These offshoots are collectively known as the Ulterior. There are no known cases where Culture ships joined a completely different civilization.
Culture ships which break away from the Culture due to some more specific disagreement (such as for refusing to be demilitarised) may also be called Absconded. Like Eccentrics, some Absconded vehicles undertake this course at the secret behest of Special Circumstances.
There are instances of non-Culture ships joining the Culture, though few species have the technological capability to produce computers of Mind-like sentience which would qualify for Culture citizenship. Such vessels tend to defect to the Culture due to its more advanced and liberal treatment of artificial sentiences.