Imperial Navy Hierarchy
Lord High Admiral
Lord High Admiral (also referred to as Lord Militant Commander or Lord Commander) is the highest rank in the Imperial Navy. There are five Lord High Admirals, each one controlling a fleet of the five Segmentae Majoris. Although all five are ranked equally, command of the Segmentum Solar is considered the most prestigious office. It is not uncommon for one of these Admirals to sit on the Senatorum Imperialis.
Known Lord High Admirals:
- Zaccarius Rath
- Drang - Lord High Admiral of Segmentum Obscurus, based at Cypra Mundi.[14a]
- Invisticone - Lord High Admiral of Segmentum Pacificus, based at Hydraphur.[14b]
- Hal Orpheus
Solar Admiral is a prospective sector commander, awaiting assignment to take command of a particular Battlefleet.[10a]
Known Lord Admirals:
- Anastasia Arkelius - Commander of Battlegroup Cerberus in the Orpheus Salient of the Achilus Crusade.
- Bastille the Seventh - Former Naval officer and current Rogue Trader, although it is unlikely he reached this rank within the Imperial Navy.
- Cornelius von Ravensburg - Commander of Battlefleet Gothic during the 12th Black Crusade
- Orson Kranswar - Commander of Battlefleet Demeter during the Pandorax Campaign
- Vortigern Hanroth
- Androvast Strophes - Former commander of Battlefleet Calixis.[10f]
- Vargaz - Commander of Battlefleet Calixis in 507.M41.[10f]
Known High Admirals:
An Admiral sees command of a Battlegroup, which is an assigned grouping of ships to handle certain situations.
- Nathaniel Horne - Commander of 'Battlefleet Koronus', or Passage Watch 27 Est, the Imperial Navy in the Koronus sector.[10e]
- Parol - Admiral Parol is the Commander of the Imperial Navy Fleet in the Armageddon Sector.
- Quarren - Admiral who defended the Cadian Sector's space lane during the 13th Black Crusade.
- Trajan - commands the Fire of Heaven starship during the beginning of the Third War for Armageddon. Presumably lost.
- Trankar - Led Imperial forces in the Battle of Bloodstar
- Usurs - Influential Admiral who was sent on a one-way exploratory mission by the High Lords of Terra in M33.
Vice-Admiral is traditionally in charge of a vanguard, and as such is usually placed in command of scouting forces of light cruisers and destroyers[10b].
Rear-Admiral is usually an administrative post, based around logistics and planning.[10b]
Commodore or Commodore-Captain is a rank within the Imperial Navy, held by personnel such as the adjutant to an Admiral or the commander of a battle-squadron.
- Teodor Naremmus - Commander of Patrol Group 686, part of Battlefleet Calixis.
- Hubert Visiter - Retired, assumed command of Perlian SDF during the 13th Black Crusade. [Needs Citation]
Lord-Captain or Flag-Captain is the rank given to the Captain of a vessel on detached duty.[10b]
- Sylvia Locke - Captain of the Dauntless Class Light Cruiser Aegis, on extended long range patrol in the Koronus Expanse.
Captain: in the Imperial Navy the rank of captain implies that the bearer has command of a ship. On board his ship, his word is law, above that of any other, save the Emperor's own. An Imperial Navy captain receives orders from a Rear-Admiral. He would then interpret these orders, and have them carried out by delegating tasks to his command staff.[Needs Citation]
Commander is a senior officer rank within the Imperial Navy held, for example, by the First Officer of an Imperial Cruiser or the captain of an escort vessel.
Lieutenant Commander is a senior officer rank within the Imperial Navy.
- Flag-Lieutenant or Lord-Lieutenant is the highest Lieutenant rank in the Navy, and may be the second in command of a ship.[10c]
- Midshipman is the rank given to 'trainee' officers, who have to pass extensive examinations before becoming a Lieutenant.[10c]
Non-commissioned ranks within the Imperial Navy include:
- Warrant Officer 
- Master Chief Petty Officer 
- Chief Petty Officer 
- Senior Chief Petty Officer is a senior NCO rank, denoted by a gold-fringed red rank sash.
- Sergeant-at-Arms[10c] or Senior Armsman is often in charge of squad of armsmen.
- Crewboss is often in charge of a shift on convicts.
- An Armsman is tasked with maintaining security, boarding enemy vessels and repelling boarders.
- A Trusted Crewman , Voidsman or Shipman (archaic)[10d] is a rank held by the skilled crew of the vessel
Attack Craft Ranks
The ranks of personnel assigned to Attack Craft differ from regular Naval ranks:
- Wing Commander - The commander of all attack craft on board a carrier ship.[10b]
- Squadron Commander - The commander of a squadron consisting of attack craft such as a Starhawk Bomber.
- Wing Captain - The commander of an attack craft such as a Faustus Class Interceptor.
- 1: Battlefleet Gothic Armada, pg. 18
- 2: Inquisitor (film) by Andy Jones & Tom Lauten
- 3: Battlefleet Gothic Rulebook, pg. 86
- 4: Relentless (Novel) by Richard Williams, [Needs Citation]
- 5: First and Only (Novel) by Dan Abnett, [Needs Citation]
- 6: Execution Hour (Novel) by Gordon Rennie, [Needs Citation]
- 7: Shadow Point (Novel) by Gordon Rennie, [Needs Citation]
- 8: White Dwarf 139 (UK), [Needs Citation]
- 9: Warhammer 40,000 5th Edition Rulebook, pg. 124
- 10: Rogue Trader: Battlefleet Koronus
- 11: Rogue Trader: Lure of the Expanse, pg. 27
- 12: Rogue Trader: Hostile Acquisitions, pg. 91
- 13: Rogue Trader: Into the Storm, pg. 242
- 14: Eye of Terror (Novel) by Barrington J. Bayley:
- 15: Rogue Trader: The Frozen Reaches
- 16: The Achilus Assault pg. 142
- 17: Dark Heresy Timeline pgs. 1-3