Built over the shell of a heavy star cruiser, the main purpose of the Interdictor-class Heavy Cruiser is to block hyperspace travel by using its gravity-well projectors, that prevent ships within its range to engage their hyperdrive motivators, and can bring ships travelling on hyperspace back to realspace if they fall within the gravity well.
Interdictor cruisers, like their Vindicator-class cousins, had the appearance of small Star Destroyers. However, their lines were broken by four large globes housing gravity well projectors which mimicked a large mass in space, restricting hyperspace travel. Nearby vessels were automatically prevented from engaging hyperdrive, and any ship passing through the area via hyperspace were forced into realspace.
As well as gravity wells, the Sienar design was also equipped with 20 quad laser cannons for short range combat against other ships. The Interdictor's hull was nearly identical to that of the Vindicator-class heavy cruiser and could support several additional weapons depending on mission profile. Enemy fire was absorbed by more than a dozen shield generators. A variant of the Interdictor design existed, equipped with two large gravity-wells rather than the usual four.
Since they were rare and costly to produce, Imperial tacticians rarely deployed Interdictors in intense combat situations. Typically, they would place them on the edge of a battle area to prevent enemy ships from escaping, or else use them to blockade planets or moons, such as Yavin 4. Interdictors also took some moments to activate their projectors after arriving from hyperspace, and once activated, the massive simulated mass they created made the ship very cumbersome to manoeuvre: there was rarely enough time for an entire fleet to make the jump to hyperspace before a newly-arrived Interdictor activated its projectors, but if a fast ship such as a starfighter could avoid enemy tractor-beams, it could often escape to the edge of an active gravity-well, and then escape.
|Interdictor-class Immobilizer 418|
| HIMS Oppressor | HIMS Inhibitor