Imperial Fleet - Adeptus Astartes: Each Chapter of the Adeptus Astartes maintains its own, separate Chapter fleet of military vessels and transports, which by the dictates of the Codex Astartes and the limitations placed upon the Astartes by the High Lords of Terra during the reformation of the Imperium after the Horus Heresy in the Time of Rebirth, is supposed to be focused on intra-system transports and planetary assault.By tradition, only the Space Marines' smaller voidcraft are purposely designed to serve as gunships that are optimised for naval warfare and fleet actions. There are some Chapters that that have always railed against these restrictions, especially those that spend all of their time on crusade or who possess no homeworld or fortress-monastery save for their fleet.These Chapters usually ignore these ancient restrictions and as a result often come into political conflict with the Imperial Navy, which fears seeing its monopoly on ship-to-ship combat eroded by the far more capable fleets of the Adeptus Astartes.Rather than making use of very tightly-defined classes of starships like the Imperial Navy, most Chapters define their voidcraft by a far broader classification system that is defined by utility, with some of the few exceptions like the Imperial Fists' Phalanx being themselves ancient relics of the Great Crusade or unique Human-built warships left over from the Dark Age of Technology or captured as prizes from other species and converted to the Chapter's use.The battle barge is the largest and most powerful type of Space Marine starship ever constructed by the Imperium of Man, and few but the most potent Chapters possess more than 2 or 3 of these extraordinarily powerful warships. Battle barges are equivalent in size and firepower to Imperial Navy battleships and were designed first and foremost for survivability under the heaviest forms of enemy fire -- a necessary trait when spearheading a planetary invasion, the Astartes' most common form of military operation requiring such a vessel.Battle barge designs back up this incredible durability with massive if usually short-range firepower to aid the Astartes in their assault operations, along with a substantial number of launch bays for Thunderhawks, other attack craft and Drop Pods. Because of the incredible durability of their armour and Void Shielding, as well as their massive arsenals of the Imperium's most powerful weapons, few known starships, save for full-scale battleships, can stand up to a battle barge in close-action void combat. Thanks to the Space Marines aboard one, a battle barge is an even more terrifying opponent during a ship-to-ship boarding operation.In addition to the battle barge, the strike cruiser is the most common type of heavy warship in Space Marine Chapter fleets. Strike cruisers are high-speed rapid response cruisers, intended for use in planetary assault and pacification operations. Strike cruisers are able to carry a company-sized strike force of Astartes to a combat zone and deploy them with preternatural rapidity.The last common type of starship found in Space Marine fleets are rapid strike vessels. These warships are small, Warp-capable escorts that include attack craft, frigates and destroyers which serve as both line-of-battle escorts for capital ships and system patrol vessels as well as infiltration ships that can be used to deploy small groups of elite Astartes behind enemy lines for a reconnaissance in force or hit-and-run raiding missions.In addition to these more common types of Space Marine warships, fleet-based Chapters often make use of a number of other support vessels such as scout-surveyors, Adeptus Mechanicus Forge Ships and the massive, mobile fortress-monasteries known as Chapter Barques (often created from converted mass-conveyors normally used by Imperial merchants for the mass hauling of cargo between star systems). Chapter Barques allow a fleet-based Chapter to avoid risking their precious stores of gene-seed and other irreplaceable artefacts and relics on the frontline of battle or crusade.Fleet-based Chapters also make use of vessels called vanguard cruisers that are refitted strike cruisers intended to undertake long-range, long-duration operations independent of support from the rest of the Chapter, often serving as reconaissance or exploratory vessels for the Chapter fleet or as heavy escorts.Vanguard cruisers are less capable of undertaking planetary assaults like normal strike cruisers because their weapons profile has been optimised for ship-to-ship combat, planetary exploration, reconaissance and boarding operations.