sentences:  Prior to this attack, no target had been sunk by torpedo where the firing ship had to consider the target's position in three-dimensional terms, where the depth of the target was variable and not a fixed value.The computation thus differs fundamentally from those performed by analogue torpedo fire-control computers which regarded the target in strictly 2D terms with a constant depth determined by the target's draught.The torpedoes were released in 17 second intervals beginning at 12