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Chapter 1: Building Starships

Alternate Armors

Source Starship Operations Manual pg. 20
While shields are the most common means of averting harm, starship engineers have experimented with a broad array of supplemental defenses to ensure occupants’ safety—anything from layering armor upon armor to projecting energy barriers that deflect rather than absorb impacts. With the proliferation of Drift travel, these various technologies have become more commonplace across different shipyards and manufactories.

Ablative Armor

Source Starship Operations Manual pg. 20
By layering inexpensive metal and composite plates over existing bulkheads, a ship can absorb initial damage to its hull before its essential components become vulnerable to attack or hostile environments. However, thicker plates are bulky and interfere with the maneuverability and handling of starships. Ablative armor grants a starship temporary Hull Points to each quadrant, usually distributed evenly. When a starship would take damage to its Hull Points, it first reduces its temporary Hull Points from ablative armor in that quadrant. Once a starship’s temporary Hull Points in a quadrant are reduced to 0, any further damage to that quadrant not absorbed by shields is applied to the ship’s Hull Points. The loss of temporary Hull Points does not count toward the starship’s critical threshold, though for all other effects, any attack that reduces a starship’s temporary Hull Points is treated as though it had dealt Hull Point damage to the target.

In most cases, ablative armor is applied evenly, distributing its temporary Hull Points between all four quadrants. However, a starship can support uneven distribution at the cost of the starship’s handling, though the vessel can add only a limited amount of extra armor to smaller hulls. If a starship’s ablative armor is not installed evenly across all four quadrants, reduce the starship’s base frame Piloting modifier by 1 (minimum –3). Reduce the Piloting modifier by 1 if the temporary Hull Points granted by ablative armor exceed the starship’s Hull Point total. A starship cannot support ablative armor if its temporary Hull Points exceed twice its standard Hull Point total.

Ablative armor can be restored only when the starship undergoes repairs, and it is repaired at the same rate and cost as standard Hull Points. A starship’s Hull Points must be fully repaired before making repairs to any temporary Hull Points provided by ablative armor.

Related Rules

Armor (Source Starfinder Core Rulebook pg. 297)

Deflector Shields

Source Starship Operations Manual pg. 20
Whereas conventional starship shields absorb attacks entirely until they are depleted, some engineers insist that shields are most effective when deflecting attacks, blunting their force or causing them to miss entirely. Deflector shield technology reduces damage from incoming attacks and increases a starship’s AC and TL, though each successive attack depletes the shields’ defensive potential. Deflector shields and conventional shields create fields that interfere with each other, so only one of these two defenses can be installed on a starship.

Fully functioning deflector shields provide a starship the defense value (DV) listed in Table 1–5 to each quadrant. Whenever the starship would take damage, it ignores an amount of that damage equal to its defense value in that quadrant. Deflector shields are twice as effective against attacks from melee, ramming, and ripper starship weapons, so the starship ignores double the amount of damage from such attacks. Any attack that would ignore a fraction or all of a target’s shields instead reduces the amount of damage the deflector shields ignore by an equal amount, rounded in the defender’s favor (e.g., deflector shields with a defense value of 5 would reduce damage from a burrowing weapon [Pact Worlds 153] by 3). While the deflector shields’ defense value in a quadrant is 1 or higher, the shields increase the starship’s AC and TL against attacks in that quadrant by the listed amount.

Whenever an attack or effect damages a starship’s Hull Points, the deflector shields’ defense value in that quadrant also decreases by 1, reducing the amount of damage they can ignore. Weapons with the array or line special property that damage a starship’s Hull Points overwhelm its deflector shields, reducing their defense value in that quadrant by 2, whereas vortex weapons that deal Hull Point damage reduce the target’s deflector shields’ defense value in each quadrant by 1d4. Any successful attack by a weapon with the buster special property (or another special property that deals reduced damage to Hull Points) reduces the deflector shields’ defense value in the struck quadrant by 2, whether or not the attack damaged the target’s Hull Points. When a gunnery check results in a natural 20, any decrease to the target’s deflector shield’s defense value from the attack is 1 greater.

When an engineer uses the divert action to send power to shields, they increase the defense value of a single quadrant by 2, or the defense value of each quadrant by 1, up to the deflector shields’ maximum defense value per quadrant. For every 150 PCU provided by a starship’s power core, increase the defense value restored to one quadrant by 1. When a science officer uses the balance action, they can adjust their deflector shields’ defense values in the same way as they would shift or distribute Shield Points, though each quadrant must have a defense value of at least 1 afterward. When a starship is not engaged in combat or otherwise taking damage, the defense value for each quadrant regenerates at a rate of 1 per minute.

Related Rules

Shields (Source Starfinder Core Rulebook pg. 302)

Fortified Hull

Source Starship Operations Manual pg. 21
By reinforcing critical starship systems with extra-thick armor, a starship’s designer can limit catastrophic failures caused by incoming attacks. A starship can incorporate one fortified hull upgrade, which increases the vessel’s Critical Threshold (CT) value by an amount based on the fortified hull’s material and the starship’s size category (for the purpose of this calculation, Tiny = 1, Small = 2, Medium = 3, Large = 4, etc.). A fortified hull is a passive system that requires no PCU to function.

Reinforced Bulkheads

Source Starship Operations Manual pg. 21
By dramatically strengthening a starship’s bulkheads and other interior walls, its designer can reduce the odds of catastrophic system damage when the starship sustains damage. Whenever the starship would sustain critical damage, there is a percent chance based on the reinforced bulkhead’s fortification rating that the critical damage effect is negated (though the attack still deals damage to the starship). The cost of reinforced bulkheads is based on the starship’s size category (for the purpose of this calculation, Tiny = 1, Small = 2, Medium = 3, Large = 4, etc.).