Often their cargo holds were filled with buoyant material to aid in flotation in case of hitting a mine and the bows were strengthened.

[1] The primary use of the Sperrbrecher was to escort other vessels through cleared paths in defensive minefields, for the purpose of detonating any mines that might have strayed into the passageways.

Even with the strengthened hull and buoyant material the ships suffered heavy losses and with the advent of acoustically and magnetically fused mines, they became ineffective.

[4] Due to their capable dual purpose armament and respectable fire control a Sperrbrecher was also an able surface combatant, significant enough to deter the WWI-era RN escort destroyer HMS Wanderer from engaging for fear of receiving "a bloody nose".

[6] To counter newer, magnetically fused mines, some ships of the Sperrbrecher type were equipped with a large electromagnet in their bows.