Hull classification symbol

A hull classification symbol, also known as a hull code or a registry, is assigned to UNSC starships of the UNSC Navy. Different types and sizes of ship have different codes. The hull code is composed of a symbol and a hull number. The hull numbers are usually assigned to each ship consecutively, though number sequences may be skipped for a variety of reasons (planned ships that were never commissioned or bureaucratic maneuvering, for example) and older numbers may be reused for new ships in order to "inherit" the identity of a particular storied vessel.

The Covenant and its splinter factions use their own system of three-letter classification codes which are assigned based on a ship's "Primary", "Secondary", and "Tertiary" features.

UNSC Navy

 * AC: Unspecified Frigate
 * AC-54 (AC-54)


 * AE: Ammunition ship
 * (AE-380)


 * BL: Evacuation craft
 * BL-9400493 (BL-9400493)


 * C: Cruiser
 * (C-709)


 * CA: Heavy Cruiser
 * (CA-70)
 * (CA-942)


 * CBC: Unspecified
 * (CBC-5)


 * CFM: 
 * (CFM-88)


 * CFV: 
 * (CFV-88)


 * CVA: Unspecified
 * (CVA-92)


 * CV: 


 * DD: Destroyer
 * (DD-439)
 * (DD-366)
 * (DD-906)
 * (DD-993)


 * DDA: Freighter
 * (DDA-147)


 * FFG: Frigate
 * FFG-045 (FFG-045)
 * (FFG-127)
 * (FFG-142)
 * (FFG-201)
 * (FFG-209)
 * (FFG-307)
 * (FFG-318)
 * (FFG-371)
 * (FFG-525)


 * FS: Corvette
 * (FS-803)


 * HEV: Drop Pod


 * INF: 
 * (INF-101)


 * IX: Experimental
 * (IX-306)
 * ONI Acrisius (IX-455)


 * OWP: Orbital Weapon Platform
 * Cairo Station (OWP-142)
 * Malta Station (OWP-143)
 * Athens Station (OWP-144)


 * PRO: Prowler
 * (PRO-46328)
 * Unidentified prowler (PRO-49776)

Covenant

 * A - meaning currently unknown.
 * C - meaning currently unknown.
 * D - meaning currently unknown.
 * O - Ordained signifies Forerunner technology incorporated into the vessel.
 * P - meaning currently unknown.
 * R - Reverence signifies that a ship can conduct reconnaissance missions, and is able to recover Forerunner artifacts.
 * S - Salvation signifies that this is a dedicated warship capable of cleansing the enemies of the Covenant with holy fire.
 * V - meaning currently unknown.

Trivia
The symbol is based on the hull classification symbol system used by the United States Navy in the 20th and 21st centuries with a few differences.