Why submarines did not chase Bismarck

Why were Royal Navy submarines not assigned to hunt Bismarck at sea?

They lacked the speed for a chase and were better deployed as ambush forces on predictable approaches.

Contemporary submarines lacked the speed to keep up with a surface hunt for Bismarck. German submarines faced the same difficulty when trying to reach the battleship to assist her. British submarines instead waited near harbor exits and approaches where she might pass. Their practical role was to intercept a ship on a predictable route.