Another shot in the dark: was it the scuttling charges that somehow went off?
Good suggestions, but no cigar! Another hint: the tests were so dangerous (deadly in fact), that the submarines the RN used to test were un-manned. A bigger hint: an 'explosion' was what the WW2 ASW ships thought they had heard...
Was it the sound of the sub breaking apart they heard?
Was it a sound of sub hitting the bottom?
More good guesses - but not right... I'll reveal the answer later today unless someone gets it in the meantime. Check those hints I gave you!
Was the "explosion" the air within the sub compressing?
Originally posted by wh1skea: Was the "explosion" the air within the sub compressing? That would be called "Implosion".
I know its an implosion, but it was stated that it "sounded" like and explosion, hence the quote marks surrounding explosion in my answer.
I wasn't nitpicking but trying to find out if VG wants a technicaly correct answer.
oh, ok. wasnt trying to bite your head off.