HMS Achilles is an Astute-class nuclear fleet submarine of the British Royal Navy commanded by Sean Ramsey, leader of the Immunes. The sub comes into conflict with the Nathan James throughout season 2.

After learning they are immune to the Red Flu, Ramsey began believing Immunes were destined to inherit the world. Ramsey and his brother Ned trained a crew of mercenaries also immune to the virus to operate the sub and started using Achilles as a floating base of operations. In his attempts to destroy the cure, Ramsey and his crew came into conflict multiple times with the Nathan James knowing the cure is on board the ship, but never ended with either side sinking the other.

In S2E12, the Achilles attempted to use an armada of American civilian ships to lure the Nathan James into a trap while setting up a shore rocket battery. During an initial exchange of fire, both the Achilles and the Nathan James were damaged by torpedoes fired by the other, but not enough to sink either ship. The damage to the Nathan James left just its 5/62-Mark Naval Gun operational with only four rounds. The Nathan James lured the Achilles near the shore to force it to the surface where Commander Mike Slattery, having captured the rocket battery, fired upon the Achilles before it could destroy the Nathan James. Combined fire from the Nathan James 5/62-Mark Naval Gun and the rocket battery finally sunk the Achilles, killing most of its crew. The only survivor was Sean Ramsey who was left trapped in the sunken wreck with no way off.


Originally in the service of the British Royal Navy, while at sea a lieutenant became infected with the Red Flu. The virus quickly spread throughout the sub, killing nearly everyone on board. Being immune to the virus, Sean Ramsey and his brother Ned where the only ones to survive. The brothers then found other Immunes and trained a new crew to operate the sub. 

According to the real-life Astute-class technical features, the Achilles has a length of 318 ft (97m), beam of 37 ft (11.3m), and a draft of 33 ft (10m). Achilles is powered by Rolls-Royce PWR 2 reactor and fitted with a pump-jet propulsor, and MTU 600 Kilowatt diesel generators. It can go at a speed of up to 30 knots (56 km/h) submerged, and has a test depth of over 300m. More than 39,000 acoustic tiles mask the vessel's sonar signature.

Its nuclear power-plants allow Achilles to stay at sea without ever having to refuel, only being limited by food and maintenance requirements.


The Achilles has stowage for 38 weapons and would typically carry both Spearfish heavyweight torpedoes and Tomahawk Block IV cruise missiles. The Tomahawk missiles were used in S2E5 to destroy the cure labs on land. The sub's Spearfish torpedoes were used in S2E5, S2E10, and S2E12 against the Nathan James. The sub is also fitted with a dry deck shelter, which allows special forces to deploy while the submarine is submerged. It is used by Ned Ramsey and his forces to board the hospital ship Solace on S2E4.

The Achilles is equipped with the Thales Sonar 2076, an integrated passive/active search and attack sonar suite with bow, intercept, flank, and towed arrays.


This is for the Immunes who commandeered the sub after most of the original crew save Sean and Ned died of the Red Flu

  • Lieutenant/Lieutenant Commander Sean Ramsey — Captain
  • Sub Lieutenant Ned Ramsey — Second-in-Command
  • Warrant Officer Class 2 Ian — Third-in-Command
  • Sub Lieutenant Max — Weapons Operator
  • Underwater Weapons Armourer Declan — Sonar Operator
  • Quartermaster Oliver — Helmsman
  • Juan Carlos — Sailor
  • Giovanni — Sailor
  • James — Sailor
  • Felix — Sailor
  • Henrik - Diver


  • Since an Astute's Tomahawk missiles only have a range of 1,240 miles, Achilles' missiles couldn't have reached all the cure labs in North America. 
  • Some of the crew are still wearing their naval uniforms from before the pandemic. 
  • In the show, Achilles is equipped with a conventional submarine periscope, however, the Astute-class has two optronic masts in place of the periscope (which carry thermal imaging and low-light TV and colour CCD TV sensors).  
  • Despite being armed with Spearfish Heavy torpedos, which can be either Wire guided or set to active or passive sonar guidance (similar to the American Mk48 torpedo but with much longer range), the torpedos in the show are shown to simply be disregarded when they miss the Nathan James. While this was probably done for the sake of the show, in reality, the spearfish could either be turned around manually by the crew if wire-guided or would have come around themselves if on active or passive guidence and would've sank the Nathan James

Behind the scenesEdit

  • Though Achilles appears as an Astute submarine on the outside, it's interior is actually based on an older submarine.

External links Edit

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