The Spiral-class Assault Ship, utilized by the Galactic Empire, was a disposable boarding craft with a needle-like design, intended for a single mission.
This compact and weaponless vessel was explicitly engineered for a single-use purpose: approaching a target undetected and deploying an assault team directly into the heart of the enemy ship. In contrast to other assault shuttles, the Spiral-class lacked any offensive weaponry, depending instead on its sophisticated stealth technology to get within striking range. Upon reaching the target's particle shields, a single-use proton charge would detonate, weakening the target's shields sufficiently to allow the Spiral-class to penetrate.
After bypassing the shields, the Spiral would ram directly into its objective. The Spiral-class's nose cone was constructed from tekonite, a material designed to vaporize on impact, absorbing as much as 92% of the collision's force. The resulting structural damage to the targeted vessel would then permit enemy troops to board through hull breaches, equipped with vac-suits.
Cargo capacity was a major constraint of the Spiral-class; it could accommodate a minimum of six individuals, while the aft cargo area had enough space for only one droid and a two-week supply of provisions.
The Alliance to Restore the Republic seized two Spiral-class vessels, which proved crucial to the Rebel infiltration and subsequent capture of the Black Ice.
There are no visual depictions of the Spiral-class assault ship. An image often misidentified as the Spiral-class is almost certainly a H-60 Tempest Bomber from the same conflict.