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Equipment & Vehicles
Thunderbird 4
Type: Submarine
Affiliation: International Rescue
Main Operator: Gordon Tracy
Appearances: List of Appearances

Thunderbird 4 is International Rescue's main vehicle for underwater rescue - a yellow mini-submarine, piloted by aquanaut Gordon Tracy.

Unlike Thunderbirds 1, 2 and 3 - all of which are capable of travelling to danger zones under their own power - TB4 fits comfortably within its own specialized pod - Pod 4 - aboard Thunderbird 2, which then transports it to where it is needed.

Sometimes TB4 must utilize other means, to get from place to place - in a different pod (eg Pod 6, in Attack of the Alligators!); via direct launching, from Tracy Island's runway; or via assistance from other transportation - notably by the World Navy's USN Sentinel (Terror in New York City), after TB2 had been incapacitated and needed to undergo a complete rebuild.

TB4 is equipped with a versatile arsenal of sophisticated gadgetry - including a missile launcher, a searchlight, a battering ram and a laser, all of which are located in the nose of the sub. It is capable of travelling on surface water (hover mode) or underwater. Its small interior is equipped with an airlock for access and exit while underwater.

Gordon at the controls

Gordon at the controls of Thunderbird 4

Technical DataEdit

  • Emergency launch jets: 4 vertical-thrust hover jets and 2 x 25 liquid fuel mini-rockets
  • Emergency launch speed: 30mph
  • Forward and reverse drive: 6 electrically driven reversible axial-flow turbine impellers
  • Length: 30 feet
  • Main turbo drive: 2 axial-flow turbines providing forward thrust only
  • Maximum speed (underwater): 160 knots
  • Maximum operating depth: 30,000 feet
  • Power source: twin atomic fusion reactors
  • Surface cruising speed: 40 knots
  • Underwater speed: 160 knots
  • Weight: 16 tons
  • Width: 11 feet


Entry/Exit HatchEdit

Located at the back of the cockpit, an airlock allows Gordon access outside the craft while underwater.


Halogen Lighting BarEdit

Hydraulic Rams With Electro-magnetic ClampEdit

Hydraulic rams incorporating electromagnetic pads.


A "paralyser" featured in The Man From MI.5.

Main article: Paralysing A Mini-Sub

Laser beam CutterEdit

Used in Atlantic Inferno, Operation Crash-Dive and Day Of Disaster.


Thunderbird 4 is also equipped with forward-firing missiles, used in Day Of Disaster (to blow away debris from the river-mud-embedded Martian Space Probe); and in Desperate Intruder (to return fire from an attack by The Hood's own mini-submarine).


Underwater Sealing UnitEdit

Primarily used to contain natural-gas eruptions on the seabed, the Underwater Sealing Unit (also known as the "sealing device") is first towed by Thunderbird 4 from Pod 4 onto the sea-surface. Both craft then submerge, to reach the danger zone. Once in position, it is then lowered over the site of the eruption. Four ballast valves are then driven deep into the seabed, to hold the unit down tight.

This equipment was used in Atlantic Inferno to seal off a natural-gas eruption.

Launch SequenceEdit

Main article: Thunderbird 4/Launch Sequence


Rescues And MissionsEdit

Main article: Thunderbird 4/Missions
See also:

Security HazardEdit

In Security Hazard, Chip Morrison sneaks into Thunderbird 2's pod and is taken back to Tracy Island, creating a breach of security. TB4 appears only in flashback footage, from the episode Day Of Disaster.

Puppet-size ModelEdit

Cross-sections (Cutaway Drawings)Edit

Cutaway drawings of Thunderbird 4 has featured in a number of books, annuals, and comics over the past 50 or so years.

Main article: History of the Cutaway Drawings (Classic Thunderbirds)