The EMS Mines. The EMS (Sehrohrtreibmine S) is a drifting decoy or anti-pursuit type of mine. It existed in three forms, which were designated EMS I, EMS II, and EMS III.

The three types of this mine employed the same mine case; they differed only in the method of floatation.

The characteristics of the mine case are as follows:

Method of firing

Weight of charge

Weight of case without flotation gear

Height of case

Diameter of case

Diameter of case includ-ing horn bosses

Case material and thickness

Method of laying

Maximum laying height

Maximum laying speed

Minimum water depths

Arming time

Self destroying Mechanism

6-day clock

The Characteristics of the three types of floatation gear are as follows:

EMS I employed a steel float designed to resemble a periscope, which is 66½ inches long and 6½ inches in diameter. When laid, the mine drifted with the upper portion of the float protruding several inches above the surface (Figure 24).

EMS II employed a camouflaged, elliptical steel float which was approximately 13 in-ches in diameter and eight inches high. This float was designed to ride flush with the surface of the water and to be invisible to pursuing vessels (Figure 25).

EMS III employed a hemispherical, plexi-glass float designed to resemble the dome of the Marder (midget submarine). The float was rainted with a silhouette of the head and shoulders of a man as he would appear when operating a Marder. This float was approxi-mately 25 inches in diameter and 14 inches high, and was designed to create the illusion of a partically submerged midget submarine with its dome exposed (Figure 26).

Work on the EMS mine with periscope was started in 1941 and completed in 1942. It was designed to be laid by surfaced U-boats against all antisubmarine craft. These mines were stowed inside the submarine and had to be handed up through the conning tower when needed. They were assembled on deck and laid by hand by a two-man team. Be-cause of handling and stowage difficulties, danger to laying personnel, and the extremely sensitive switch horns, only a few of these mines were used operationally, and the pro-ject was abandoned. During the same period, experiments were conducted with the EMT mine. This mine employed the same case as the EMS, but the periscope was replaced by a camouflaged elliptical float. Later, the EMT was designated the EMS II, and the EMS mine became EMS I. The EMT mine was primarily designed as a drifter for surface-craft laying; however, it was abandoned at the same time as the EMS, for the same reasons.

In the fall of 1944 the German Sneak Attack Command (KDK) requested a floating mine with a plexiglass cupola attachment to resemble the dome of a midget submarine. These mines were intended to be laid by small motor boats or "Linsen" boats as decoys against patrol craft in heavily protected sea lanes. The first consignment of cupolas with the silhouette of a midget submarine operator for use with the EMS mine case was deli-vered in November 1944. Very few of these modified EMS mines were laid, because of operational difficulties and a small supply of cupolas. This modification had no German designation, and consequently, for purposes of identification, it is referred to as EMS III.

Figure 24 – EMS I Mine

Figure 25 – EMS II Mine

Figure 26 – EMS III Mine