“a 1 kiloton nuclear antisubmarine bomb weighting 1,600kg”
That seems to be pretty massive for such a low yield. Compare to Davy Crockett or W51.
Unless it is housed in a maneuvering vehicle- even then that’s heavy.
Torpedo has entered the water.
High speed screws.
Torpedo has acquired.
I am not an expert but there is no compelling reason for a 1 kiloton bomb to weigh that much unless there’s other stuff involved.
My guess is there’s other stuff involved.