EMC II Mine. The EMC II existed in the six types shown in Figure 49a. The general characteristics of each of the various types are as follows:

EMC II with Upper and Lower Antenna

Upper antenna

Lower antenna

Depth setting

Max. depth of case

243 ft.

EMC II with Tombac Tubing

Tombac tubing is an anti-sweep cable fitted over the mooring cable.

Tombac Tubing

Depth Setting

3 to 190 ft.

EMC II with Lower Antenna

Lower antenna

Depth setting

3 to 190 ft.

EMC II with Cork-Floated Upper Antenna

Upper antenna

Depth setting

3 to 190 ft.

EMC II with Chain Mooring

Chain mooring

Depth setting

3 to 190 ft.

EMC II with Chain Mooring and Cork-Floating Snag Line

Chain mooring

Snag line

Depth setting

40 ft.

In 1940 the eighth horn was removed from all German base plates, because experien-ce had shown that this device was often actuated in heavy seas. The upper antenna was abendoned in 1941 because of the excessive numbers that broken loose in rough waters; and, in 1943, the lower antenna was abandoned because of the copper shortage then prevalent.

Experiments were conducted to obtain delayed rising of the mine. A fifty-foot bight of the mooring cable was flaked on the top of the anchor and kept in a locked position by a six-day clock. In operation the mine would plant at its set depth and, when the clock had run off, rise 50 feet. This idea proved unworkable because of the excessive strain created on release of the bight.

In 1944, because of a critical shortage of lead, steel horns were developed and sub-stituted for the standard Hertz lead-acid horn. The steel horns were so constructed that the metal and welds would not part of bent to an angle of 90 degrees. A pull of approxi-mately 130 pounds is sufficient to bend the horn and break the inner vial. Although the lead horns were considered superior, the steel type proved satisfactory operationally.

Early in 1944, the German Navy experimented with a 32 second clockwork release de-vice to replace the standard dash-pot plummet delay. This clockwork was standard Luft-waffe equipment used to obtain delays in the opening of cargo parachutes, etc. This de-vice was simple and easy to produce. It operated as follows:

The time delay desired, up to 32 seconds, was selected by turning a dial on the face of the clock. The clock was simultaneously wound and started by pulling a wire lanyard at the base of the device. At the opposite end, another wire was run off; the wire lan-yard was snarped in by the spring-loaded clock drum and the safety pin withdrawn.

When, with relatively minor casualties, the Allies successed in penetrating the field of moored contact mines laid off Salerno, the German Mining Command suspected that ASDIC was being used to located the moored mines. Accordingly, they gave some thought to the development of a mine case that would resist location by such methods. They sought to attain this end by coating mine cases with rubber and using special type paints. To this extent, their efforts paralleled those of the German Submarine Command, which sought to apply anti-detection methods to submarines. However, the foregoing methods proved unsatisfactory, and it was finally decided that the best anti-detection type mine would be one employing an all sponge rubber case. Limited experimentation was commenced to determine the response of various types of synthetic sponge-rubber to ASDIC. The end of the war caught these experiments in their early stage. Conse-quently, no mine cases of this type were actually built.

Both models of this mine were laid operationally. (A field of EMC I mines was laid in the South Pacific, some of which were recovered by U.S. Navy Mine Disposal Personnel.)

Figure 10 – EMC II Mine

Figure 11 – EMC II Mine - Cross Section

Figure 12 – EMC II Mine with 80-ft. Rubber Snag Line

Figure 13 – EMC II Mine with 20-ft. Mooring Chain