Thunderbirds are go

Thunderbird 4

A small utility submersible for underwater rescue, Thunderbird 4 is carried aboard Thunderbird 2, nearly always in Pod 4, although it was once transported in Pod 6 ("Attack of the Alligators"). In the episode "Terror in New York City", Gordon launches the craft by emergency procedure, from the Thunderbird 2 hangar and sliding along the island runway, with the runway's overhang automatically dropping into the sea as Thunderbird 4 approaches it. However, the submarine's slow speed renders it impractical for Thunderbird 4 to travel on its own; when Thunderbird 2 was temporarily out of action and Thunderbird 4 required, Jeff Tracy contacted the navy vessel Sentinel - the fastest ship in the fleet and unintentionally responsible for incapacitating Thunderbird 2 in the first place - to give Thunderbird 4 a lift to the danger zone. Thunderbird 4 is 9 m long and 3 m wide, this makes it the smallest of the Thunderbirds vehicles, but not the smallest of the pod vehicles. It is fitted with an adjustable searchlight which can be raised or lowered to reveal a variety of rescue instruments, such as cutting lasers, electromagnets, demolition rockets and battering rams, which can be extended from the nose section. Thunderbird 4 is piloted by aquanaut Gordon Tracy.

Thunderbird 4 does not play an active role in the films Thunderbirds Are Go and Thunderbird 6. It does however appear in the opening title sequence of Thunderbirds Are Go. In Thunderbird 6, Jeff Tracy gives a "run down" on each of the Thunderbirds machines, where Thunderbird 4 makes a brief appearance. It also appears in the 2004 live action film with an updated design. However, it is handled by Alan Tracy instead of Gordon (Albeit because Gordon is unavailable).