The EMC I Mine. The original EMC mine was completed in 1924. (Figure 7). It utilized a bronze base plate and an eighth horn (KE) which was placed on top of the mooring safety switch. In 1936 the mine was improved. The eighth horn was moved to the side of the mooring switch; a soluble plug was substituted for a dash-pot type of delay system; fit-tings were provided for antenna and scuttling devicies; and the base plate parts were redesigned to give greater life and watertightness. The improved model designated EMC II and the original type redesignated EMC I.

Figure 7 – EMC I Mine

Figure 8 – EMC Mine Afloat