Plot hole: In order to build up suspense, Virgil and Brains stand on the Crab Logger as its dangerous fuel is pumped out, despite the fact that it is hanging on the edge of a precipice. In fact they could have left as soon as they had plumbed in the pipes to empty the fuel tanks - the whole procedure is controlled by Scott in Thunderbird 1 and they make absolutely no contribution to the operation at all. They do not need to disconnect the pipes; they are left behind and dropped from Thunderbird 1 as planned. They just stand there chatting about how much danger they are in until jumping clear at the very last second. Silly buggers.
Continuity mistake: During the battle a railing on a pirate ship falls off, only to be seen in the next shot intact, then missing in a subsequent shot.
Visible crew/equipment: When Phones is unravelling the secret plans, a hand can be seen pulling him back to help unravel the plans.