Fixing Tigerfish or accelerating Spearfish for 1982

HMS Conqueror's use of the older Mark 8 is cited as evidence of the lack of confidence in Tigerfish. A more effective submarine force would therefore need a serious effort to fix the modern torpedo. Spearfish is preferred as an alternative, but the discussion puts its historical production in 1988, too late for the assumed war. Bringing it forward would require changing the development schedule well before 1982. The answer leaves the choice between improving Tigerfish and accelerating its replacement unresolved.