The starships that make up the Imperial Starfleet are a significant source of much debate. In particular, the classes of various Star Destroyers only briefly seen and perhaps poorly illustrated are often hotly discussed, with one side claiming they are a new class of ship and the other refuting that, stating that they are merely modifications to an existing class, or perhaps so poorly drawn that they are meant to be stock ships. The purpose of this article is to discuss various ships, and the Imperial design philosophy. A later article will examine the New Republic fleet in a similar manner.

Like evolutionary biology, an armed forces division tends to utilize the most successful design until something more useful comes along. For example, the AT-TE walker was supplanted by the AT-AT, and the AT-PT became a cornerstone for the newer AT-ST. Other examples can be provided, but the basic idea is that each design has its niche to fill, and while redesigns may alter its purpose or make an older design completely obsolete, it is rare to see such and generally is implemented to correct deficiencies with a particular class.

There are four basic capital ships in the Imperial Starfleet. Each has been modified for various reasons, but the basic design remains the same.

I. Victory-class Star Destroyer

The Victory-class Star Destroyer is primarily for planetary and orbital platform assault. Its weaponry is focused around concussion missiles, with a comparitive handful of energy weapons to defend itself from other capital ships. While missiles can be used to devastating effect against enemy warships, the order of battle has shown that energy weapons are the primary means of capital ships to deal damage. Missiles tend to be used for focus fire, ambushes, and assaults upon stationary platforms. Orbital bombardment using concussion missile salvos is a possibility, although collateral damage would be significantly higher than turbolaser bombardment.

The major modification to the original Victory-class is the aptly named Victory II-class Star Destroyer, or Victory-class Star Destroyer Mark II. This warship sacrifices the missile power of the original Star Destroyer for significant upgrades to the energy weapons aboard. The redesign of the Victory-class Star Destroyer makes it into an effective space combat vessel. Since the VSD is also atmosphere-capable, orbital bombardment via turbolaser salvo is also an option.

II. Imperial-class Star Destroyer

The Imperial-class Star Destroyer, first and foremost, is a space superiority vessel. While it plays the role of a mobile siege platform, it is dependent upon its contingent of TIE Bombers, ground troops, and "walkers" to assault a planet's surface via methods other than pure destruction. The true purpose of this vessel must primarily be space combat, where it excels. Its large complement of turbolasers and ion cannons allow it to inflict significant damage upon other ships; for this reason since its introduction it has become the backbone of the Imperial Starfleet.

Glaring deficiencies, notably the armor and shields, in the original design caused Kuat Drive Yards engineers to produce the Imperial II-class Star Destroyer. The hull and shields have been reinforced, and the armament increased. The basic design of the warship remains unchanged, however, and therefore the "Impstar Deuce" is suited to the same role as its predecessor.

III. Executor-class Star Destroyer

The so-called "Super Star Destroyer" is likely the most hotly debated topic among fans. While it is clearly conceived as a heavily armed ship capable of punishing any attack upon it, the ship itself is vulnerable to a much larger fleet of smaller ships. For this reason, Darth Vader kept no less than five Imperial-class Star Destroyers in formation with his Executor -- the infamous Death Squadron. Due to the massive construction cost of such a warship, they are relatively rare. Generally they serve as command ships for fleets, although in rare situations they have been used to take the place of an entire fleet by themselves.

IV. Immobilizer-418 Interdictor-class Cruiser

A unique and special ship, the Interdictor cruiser fills a formerly absent role in the fleet. Hit-and-run tactics by the Rebellion can effectively be curtailed by the presence of a single Interdictor to prevent the retreat of attacking forces. The gravity well generators on this ship force enemies to remain at sublight speeds, allowing a response to ambushes or fast assaults upon worlds or stations. Similarly, they also ensure that ambushed enemy ships cannot flee to hyperspace.

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Each required role must therefore be filled by a specific design of ship. Existing classes may be modified for alternate mission requirements; such is the case even in today's seaborne navies, and may be seen in the redesign of the Executor-class Star Destroyers after the debacle at Endor. Rather than build an entirely new class of warship, Kuati engineers added a third shield generator located on the centerline. Similarly, modifications were made the Imperial-class Star Destroyer superstructure. Modifying a warship is significantly cheaper and allows the ship to fulfill its new mission profile much more quickly than designing, testing, and commissioning a completely new class of ship.

What roles are required to allow a fleet to function?

1. Command ship. This role can be assumed by any ship, and is in fact merely a designation that the fleet's commander is aboard. Larger fleets may have multiple command ships, as seen at Endor. The purpose of this ship is to coordinate fleet movements and allow for large-scale tactical maneuvering. Where present, an Executor-class vessel tends to be the major command ship. However, Imperial-class and even Victory-class Star Destroyers can and have assumed this role.

2. Primary combat. This role is the province of the Imperial-class Star Destroyer. Built in such tremendous quantities that they are almost expendable, the warships are designed to both give and take massive amounts of punishment.

3. Planetary assault and interdiction. This role can be fulfilled by any Star Destroyer, depending on mission profile. For precision assaults, a high number of energy weapons are more effective than a bombardment of concussion missiles would be. A Victory-class Star Destroyer likely could not have effectively filled the role of Lusankya at Borleias during Operation Emperor's Hammer, or the role of Direption at Liinade III. For mass terror, however, either suffices, and the random nature of concussion missiles might indeed be preferable.

4. Starship interdiction. Almost exclusively the province of the Interdictor-class cruiser, recent ship designs such as the modified Defender-class Star Destroyer or the massive Eclipse-class Star Destroyer have incorporated gravity well generators into an assault platform, eliminating the minimal defenses of the original design.

5. Starfighter and troop transport. This role is effectively filled by the basic Star Destroyer design. Each ISD carries six starfighter squadrons, the composition of which can be altered by mission profile. Each Executor-class SD carries twelve starfighter squadrons. The number of troops aboard each ship is enough to mount a concerted war effort. If additional units are required, the Empire possesses the modular Strike-class Cruiser, specifically designed to be easily convertable between troop carrier, starfighter carrier, assault platform, and various other designs.

Perhaps the greatest argument for modularity is the aforementioned Strike Cruiser. It is amazingly effective because it is easily modified for any mission profile, and that is its greatest strength. Easily-modified ships like Termagant allow the Empire to change the makeup of its fleet without building entirely new vessels, and that is an important asset to any fleet.

The question to answer then becomes, what role do debated ships such as Allegiance orHarrow fill? The illustrations on these ships have caused some to place them as entirely new classes of warships. Is this sensible, given what we know of the Imperial fleet?

At Mon Calamari, Allegiance was acting as the command vessel of the Emperor's fleet, transmitting images of the attack on Mon Calamari to Byss. This is not a role which requires a new class of ship to assume -- it is in fact perfectly in line with how we have seen Executor-class vessels be used previously. Additionally, no other ships of the supposed "Allegiance-class" have ever turned up in production! Designing just one ship of a given class is wasteful beyond measure. Even Executor, once thought to be a unique ship or close to it, has been shown to have sister ships operating in numerous Imperial fleets. Anomalies like Eclipse are given to a specific purpose. In the case of Eclipse, it was the Emperor's personal Star Destroyer, and therefore without a sister ship for a specific reason. And even with that caveat, the Sovereign-class Star Destroyers are much the same ship as the Eclipse-class, but merely scaled down slightly to maintain the Emperor's superiority.

Similarly, Harrow is fulfilling the basic mission profile of a Victory-class Star Destroyer. The modifications to its superstructure are certainly not outside that which KDY is capable of, and may be designed to give it an advantage in space combat. Again, no design twins of Harrow have ever been found, and that in itself is a compelling argument against it being a new class of warship.

Are any of these arguments definitive? By no means. However, they are certainly plausible. Modifications to existing vessels are cost-effective, useful, and enable the ship to execute its mission without requiring the design, construction, and crewing of an entirely new warship. The lack of any similar ships is also indicative of unique modifications performed to a specific vessel rather than a completely new warship.