[1] The Hertz horn triggers in British naval mines had been copied from German World War I contact naval mines whose Hertz horn triggers were more reliable than their British equivalents.

When struck by a ship, the horn would break and release the acid into a battery, detonating the explosive.

[1] Later in the interwar period, the development of Hertz and switch horn mines were merged into one project.

[1] However, defensive mines would have also denied routes to enemy ships, so this must also be considered when judging their effectiveness.

The MK XVII contact mines are said to have been deployed by HMS Abdiel (N21).

[5] This ship's minelaying WWII predecessors were also likely to have deployed MK XVII contact mines at some point in their careers.