The keel depth of the Ships is not in the manual.. Its a picture of a keel drawn in the Torpedo depth control graph when you ID the target.
If you use Auto TDC you have to turn on the TDC then ID the ship.. And then turn off TDC again to go back to auto and the graph will now have a picture of a hull and its depth in the graph.
(the upper left corner under your torpedo tubes) Same place you adjust the depth of torps.
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