People on Sheares Bridge in front of the two durians bidding farewell to LKY. It was a very wet day.
Look at the picture carefully. Look at how the steel plates folded, outwards and upwards. It looks like the explosion was from inside or from below. An internal accidental, hitting a mine below?
If it was hit by a torpedo, the steel plates would be folding outwards from one side. You make your conclusion.