Specific tasks require specific tools; the primary tool for The Imperial Navy are its ships. It is these ships that make up the forces of the Navy, and since there are many tasks, there are as many types of ships. The categories by which military ships are categorized derive from ancient seaship classifications,  but have become tradition for many millenia by now. These common starship types are named by size or abilities- a destroyer, for example, is a frigate-sized ship for specific tasks. The following chapter is intended to give an overview over the IN starships and small craft by type; specific classes of ships can be found in part four of this work. The crews of the Imperial Navy's vessels are usually of a quality directly related to the vessel's size: the larger the ship, the better (or more experienced and skilled, to be accurate) the crew.
 

a) Fighter Craft And Boats

These are ships that have not large enough a hull to allow for a wide enough a lanthanium grid that would be required for a jump drive. They are typically carried aboard larger ships or stationed at planetary bases. The purpose of the smaller vessels which do not have a primarily combat-oriented task can be divided into two categories:
First, transport craft, intended to transfer personnel and cargo between ships or ship and planet (also used as lifeboats when neccessary), and second, auxiliaries that are intended for supporting their motherships, such as fuel skimmers and repair craft. Both categories of boats are rarely used in battle and are usually crewed by NCO's.

Fighters, on the other hand, are a different thing. These small vessels are used for a broad variety of missions, from reckonnaissance and patrol missions to space policing and planetary defense. Wherever smaller (and thus cheaper) vessels of shorter range can do the job, the fighter is the craft of choice.For mass battles, on the other hand, larger ships are preferred, since a system defense boat twenty or forty times as large as a fighter can have almost the same maneuvering rate, but heavier armour and weaponry. Especially using missiles in a large battle is a hard thing to do from a fighter; missiles need a magazine, for which not much space is left on a fighter vessels, but plenty of room on a larger ship. In addition, in space combat, armour is much more important than being able to evade; heavier ships can take more damage per dtons than fighters.

There is one advantage that fighters have over larger ships, though: They usually have more firepower per dton. Large ships usually have only one mount per 100 dtons of hull space, while fighters can have one mount per vessel. Considering that the typical IN or reserve fleet fighter is a Rampart or Iramda class craft (or a similar design) measuring merely 10 dtons, this is ten times the relation of most larger vessels (perhaps except destroyers). This means that larger numbers of fighters are also well suited to "finishing off" damaged enemy vessels when time is critical, and the IN is well aware of this fact.

There are no dedicated "fighter carrier" designs in the Imperial Navy. Instead, most larger ships like cruisers and above have space for a couple of these smaller combat vessels.

The crews of fighter craft are always officers in the IN and the reserve fleets, having one or the more prestigious jobs due to being in command of a single vessels (though they are usually not tactically independent units; but this is generally not perceived by the media- all they see are heroes in small and deadly craft). Conditions vary for system navies, though.

Larger groups of fighters are usually organized into squadrons and wings; a squadron is a group of ten to twenty fighter craft, a wing is a group of two to six squadrons. Exact strength of these units varies from subsector to subsector; as usual, the local fleet admirals are given free hand for the organizaton of their forces.

b) Small Starships- (Corvettes, Frigates, Destroyers)

Patrol and reckonnaissance on the strategic scale is the task of the small ships of this category, generally spanning from one hundred up to about a thousand dtons. They do usually not operate away from a larger fleet or a Navy base for longer than four weeks; being to small for being a real threat for any serious system defense effort. On a tactical scale, they are usually used as relay stations for communication around larger celetial bodies that are patrolled by fighters, or they fill in the role of the fighter if these are either not available or enemy force compositions dictates heavier but less maneuverable reckonnaissance units. In poeacetime, these vessels show the flag at less important and/or less developed systems of the Imperium. They can also be quite commonly found in convoy protection and anti-piracy operations. The three categories of the small starship type are:

-Corvettes. Sometimes called scouts, or escorts. By Imperial naming conventions, corvettes are military starships no larger than 400 dtons. These tend to be rather light in weaponry and armour, since crew quarters and fuel tankage requirements leave less room than on a system defense boat or battle rider of the same size. The emphasis in corvette design is usually being cheap and quick to build in the first place. The crew of an Imperial Navy corvette usually consists of young officers and likewise NCO'S and crewmen, and therefore fairly unexperienced in combat. For the young officer, it is a dream command however, since it offers the opportunity to become a ship's commanding officer very soon. Commanding officer is usually a Lieutenant Commander; there are a few exceptions where the CO of a corvette is a Lieutenant; these officers are usually straight on their path to promotion. Corvettes have rarely more than three additional officers on board: a First Officer, who is the second in command and the CO's assistant for anything ship-related (usually a Sublieutenat or, more often, a Lieutenant, but always of the Line branch), a ship's Chief Engineer (who is responsible for logistics, the ship's overall technical ability, damage control and the like), usually a Sublieutenant or a Lieutenant, and the Ship's seconf Officer, whose job it is to do whatever the other officers aboard assign him to do (this is rather an apprentice job; normally, Ensigns or Sublieutenants are predestined for it.). In addition, there are a few Petty Officers (most of them being 3rd and 2nd class) and a ship full of Spacehands of all three ranks. There are no ship's doctos aboard these small vessels; a Petty Oficer of the Medic branch fills in the job in most cases.

-Frigates. Starships ranging from 400 to 1000 dtons. Frigates are intended for shielding larger units such as battleships, battle rider tenders or auxiliary craft in the line of battle. As a consequence, they are usually more heavily armoured (and sometimes even equipped with meson screens, nuclear dampers or rarely even black globe screens) than destroyers (see below), since they will have to take larger amounts of damage. Logically, this feature makes them also well suited for protecting important convoys and other vulnerable targets. Unfortunately, their heavy armour costs them maneuverability and/or offensive capability.

-Destroyers. These are starships of the same size as frigates, but with the opposite design philosphy in mind: Heavy offensive capability and maneuverability at the cost of the ability to withstand heavy fire. Their role is to strike at enemy capital ships and other large targets where time for destruction is more critical than the survival of the attacker. Destroyers often operate along with fighters, though fighter carrying destroyer designs are rare. Destroyer almost never operate alone without larger ships. Especially auxiliary craft are a need for these vessels, since onboard repair is not always possible. Both frigates and destroyers have a commanding officer, usually a Lieutenant Commander or a Commander, several First through Fourth Officer positions (a Lieutenant Commander or Lieutenant of the Lien Branch being the First Oficcer, and an Ensign usually being the last in the chain, just as with corvettes), a small staff of two or three ship's engineer officers (starting at Lieutenant Commander and ending at Ensign or Sublieutenant), about half a dozen of Petty Officers (of 3rd to 1st class), and a lot of Spacehands. The crews' mentalities are usually fitting the particular job of the vessel; a frigate will have more careful officers than a destroyer, which usually leads to a certain rivalry between the crews of such ships within a fleet. The medical staff of these vessels is usually limited to a single, quite young ship's doctor. On the rare ships that do have a few fighters aboard, the pilots (sublieutenants, at most) of these craft add to the crew, of course.

c) Medium-Sized Starships- Cruisers

Cruisers are generally starships from 1,000 to 100,000 dtons. The term is not very meaningful regarding the tasks and roles of these ships, though. There are various variants in design philosophy; those most commonly enountered in the Imperial Navy are listed below:

-Standard cruisers. These are the starships most commonly found as cruisers in the Imperial Navy. A standard cruiser's job is, well, to cruise. In other words, it is designed to operate independently for longer periods of time even in hostile space. Their task is to disrupt trade and resupply lines, gather data about enemy logistics, attack unexpectedly and deep within non-Imperial territory. As a consequence, cruisers tend to have long legs, that is, high jump capacities, the ability to do even more serious repairs indepently, raher heavy armour with less emphasis on offensive capabilites. The ships of this type are sometimes labelled frontier cruisers.

-Scout cruisers. Similar to the standard cruiser, but with more sensor and stealth capability, intended for larger and longer reckonnaissance missions beyond Imperial borders. They are usually, but not always, operated by the Imperial Interstellar Scout Service, and are rare to be encountered, not only because their numbers are not large in the Imperium.

-Battle cruisers. Ships intended for the line of battle. Also known as "pocket battleships", which describes their roles quite well. They tend to be less maneuverable both on a strategic and on a tactical scale, but are heavily armoured, equipped with the most deadliest weaponry. The larger designs usually carry a number of smaller craft, especially fighters.

The cruisers of the Imperial Navy have a more sophisiticated crew structure than the smaller vessels. While the officers of corvettes, frigates and destroyers tend to be generalists, capable of doing anything to ensure the ship's proper operation, the officers aboard a cruiser are more specialized. Still there is a commanding officer, usually a Commander or, on rare occasions or on the largest cruisers, a Captain. Usually one rank below, there is the First Officer, a Lieutenant Commander or Commander of the Line branch. But below him or her, there are the department leaders: One for each branch aboard the ship. A Gunnery Officer, a Chief Engineer, a Chief Flight Officer (if the cruiser carries fighter craft), a Ship's Doctor (from Lieutenant Commander to Commander in rank) and a Chief Of Operations (of the Line branch), whose job it is to coordinate the ship's internal affairs and who is in charge of ship's discipline (including representative tasks like commanding an honour formation when in port somewhere). This "second level" below the CO is usually of the rank of Lieutenant or Lieutenant Commander. Below them a small group of Officers and Petty Offciers(with only a few Chiefs among them) assists them in their repsective tasks, backed up by several Spacehands.
 

d) Battleships And Dreadnoughts

These ships are often called "capital ships" (though some Imperial Navy personnel include the larger cruisers in that category), and this is just what they were until the rise of the battle rider concept within the Imperial Navy: the Navy' capital craft. These are vessels larger than 100,000 dtons, intended for the line of battle, and no Domain has more than a handful of them. Among these most dreading ships, the two main desing philosphies that can be found among cruisers are also quite commonly encountered:

-Battleships are heavily armoured, equipped with the deadliest weaponry and defensive capabilites, but have both realitvely low jump numbers and maneuvering capabilites. Faster ships such as frontier cruisers can easily avoid such a vessel, but if they don't, they are glowing metal. These ships are usually used for strategic defense of important cluster systems. It is also common for these ships to carry a large amount of small attack craft and being accompanied by a number of frigates and two or more battlecruisers to shield them against nuclear missile attacks. A battleship task force is usually capable of defeating any planetary defense.

-Dreadnoughts, on the other hand, are the mobile task forces' cores. Highly jump capable, they are the aces at the respective Archdukes' strategic hand. Their task is to strike deep into enemy territory and bind forces that would otherwise support and resupply hostile forces within Imperial space. As a consequece, they are capable of even the most serious damage repair procedures without the help of any external facility. Their maneuvering drives, though are usually not intended for high rates of accelleration and use their hull space rather for weaponry than for maneuvering drives.

The crews of these capital ships are part of the cream of the Navy. The CO is usually a Captain, sometimes a Commodore, with a First Officer at the rank of Commander at his side to assist him. The command structure follows pretty much the patterns described for cruisers above, but with more personnel, of course. Skill and expertise among these crews is almost always excellent.
 

e) Battle Riders

These are combat vessels without a jump drive, having heavier armour, weaponry, and maneuvering drives instead. They can be found in any size, but battleship-sized battle riders are rare (these vessels are commonly known as "monitors" and are usually not carried by a tender, but allocated to important systems for defense. See "system navies" for more information.) The Imperial Navy relies heavily on battle riders; experiences from the Fourth Border War and the Solomani Rim War have led to the conclusion that the advantage of ships that are able to use a larger portion of their displacement to directly combat-relevant equipment is decisive for the outcome of battles, even when taking into the account that a tender is needed to carry the non-jump-capable vessels to the point of action. Therefore, the mostvdreaded fleets of the Imperial Navy do not maily consist of battleships, but of battle rider squadrons. A battle rider sqadron normally consists of the eight to ten battle riders of a single battle rider tender (see below); but as usual, some local Fleet Admirals prefer to organize them in smaller or larger groups, depending on local circumstances. The crews are usually above average, but the command structure is similar to starships of the same size. Normally, no ship's doctor is prsent, though; instead, the battle rider tender carries a large complement of medical staff with it.
 

f) Battle Rider Tenders

The large jump-capable vessels that carry the battle riders into the system where the action takes place are called battle rider tenders. These ships are normally equipped with inferior maneuvering drives, only light weaponry, but with heavy armour and fast jump drives (jump-4 and higher). All of them have the most adavanced stealth capabilities available at the time and place of the construction ofther ship. They all have expendable Lanthanium grids to be able to take the docked battle riders with them into jump space; in normal space, these are retrieved and carried within special armoured containers along the tender's hull.

Generally, battle rider tenders stay out of the 100-diameter-limit of larger celestial bodies in a system, and stay at lowest noise level possible. Their crews are average at best, only their rather large medical staff is of the better part of the Imperial Navy.
 

g) Auxiliaries

Finally, the Navy's ships rely on support. They must be repaired after battle, but also be maintained in peacetime, must be refueled in time, must be possiblx moved by one or more tugs into a Imerpial Navy highport facility, and must be inspected from the exterior at regular intervals. The tools for these tasks are called auxiliaries. The exact type and class of the available auxiliaries varies from subsector to subsector; such admissions are usually given to smaller and less advanced yards in te backwater region the respective subsector, in order to help to delvelop the respective systems and to cut off costs. The only standardized design of this category may be the Modular Cutter, which is a design used by many subsector fleets throughout the Imperium. Crews of these vessels are below average, to be polite. But without them, the more skilled members of the Navy couldn't do their job, and this is usually kept in mind.