The Deep Water Exo-Suit is deigned for rescues that involve extreme pressures and conditions underwater. The suit was first seen worn by Alan Tracy in Deep Search and secondly by Gordon Tracy in Up from the Depths Part 1, both rescues were set in extreme conditions such as the freezing temperatures and strong currents of Jupiter's moon Europa as well as deep within the depths of the Mariana Trench.
In Up from the Depths Part 1, Gordon is seen in the back of Thunderbird 4 equipping the suit before he uses the plasma cutter to cut a hole in the hull of the craft to escape, before it is crushed and destroyed.
Gordon's deep water exo-suit was freshly installed in Thunderbird 4 when it was put to good use. It is yellow in colour and has "4" written on both shoulders. Gordon's suit has a hyper-charged plasma cutter on the right arm that was very powerful at a short range with the standard communications and controllers on the left.
Alan's deep water exo-suit is red with a white "3" on each shoulder. It has two wrist controllers, one for Thunderbird 3 on the left and for Thunderbird 4 on the right.
- While Deep Search is the first time we see the suit being used, the reveal of the suit being 'new' was in Up from the Depths Part 1, creating a continuity error. It is unknown why we see it in this order and not the other way around.