Data from Spectrum files withheld.  Because of security reasons, the Spectrum organisation will not release many of the specific details of the Spectrum Clam Sub.

Inside the USS Panther II, which is a Clam Class submarine. Picture from 'White as Snow'.

Built forty years ago, and based of the original 'Reaper' prototype, the Clam Class submarines were once the backbone vessels of the World Navy, and had a successful run as patrol and escort vessels.

The Clam class was upgraded in the 2050s with redesigned bridge and conning tower sections. Extra missile launchers and onboard VTOL aircraft capabilities were added as well. The VTOL aircraft capability allows for one light, VTOL plane to be launched when the craft is surfaced.

Within the World Navy, the Clam class are now heading for obsolescence, due to the introduction of the Barracuda class subs. However, five, and later a sixth, Clam class submarines were modified and seconded to Spectrum, when the organisation was formed. These will continue to be used for a number of years.

The Clam Sub has a length of 420 feet; a beam of 60 feet. When fully submerged, it weights 7000 tons. It can travelled at a speed of 80 knots submerged, and has an unlimited range . Its turbines run on nuclear power.

(Sources: TV Century 21 material (Annuals, books and magazines), Engale Marketing's Century 21 magazine, Issue 15, Winter 1995, Fleetway Magazines, Captain Scarlet & the Mysterons book by Chris Drake & Graham Bassett, Complete Book of Captain Scarlet by Chris Bentley… all related to TV Century 21 material.)