BM 1000 I. The BM 1000 I was the original model of the BM 1000 mine series and was developed in 1940. Its characteristics are as follows:

Description of case:

Shape

Cylindrical, with ogival nose and truncated cone dome on tail; fitted with break-off tail section; possibly fitted with false nose

Material

Manganese steel

Length of case

64 in.

Diameter

weight of charge

Total weight

Max. effective
distance

Min. effective
distance

Description of External Fittings.

Rheinmetall bomb
fuze

3 in. diameter, on top center line 4 ft. 2-1/2 in. abaft the nose

Suspension lug

On top center line, 3 ft. 0 in. abaft the nose

Figure 72 – BM 1000 I/II Mine with M 102 Unit

Figure 73 – BM 1000 I/II Mine with A 105 Unit

Dropping heights depend on: speed of the plane, depth of water, and whether or not the mine is fitted with a "Bugspiegle" or parachute.

Without either a "Bugspiegle" or a parachute, the BM 1000 I can be dropped from heights of 325 to 6,500 feet in depths of water from 17 to 115 feet at speeds up to 285 m.p.h.

With a "Bugspiegle" it can be dropped from heights of 325 to 23,000 feet in depths of water from 17 to 115 feet at speeds up to 285 m.p.h.

With a parachute (LS 1 or LS 3) it can be dropped from heights of 325 to 23,000 feet in depths of water from 17 to 115 feet at speeds up to 285 m.p.h. with the LS 1, and up to 400 m.p.h. with the LS 3.

Operation. When the mine is dropped, the Rheinmetall fuze condenser receives a charge and a split lanyard attached to the false nose is pulled, thereby igniting the two small-delay detonators on the charge case. After a short delay, the delay detonators fire, driving the securing rod forward and thereby removing the small nose. Air travel then forces the petals outward and they fall away. Upon impact with a surface, the Rheinme-tall bomb fuze operates as follows:

If the rate of deceleration is 20-200 g, as in the case of impact with a soft surface such as water or loose earth, the trembler switches close, firing the igniters in the mas-ter switch. If the mine does not reach a depth of 24 feet within 90 seconds, it will fires as a delayed-action bomb. If the mine does reach the proper depth within the appointed time, the firing unit is put into the circuit and starts its arming cycle.

If the rate of deceleration is greater than 200 g, as in the case of impact with a hard surface such as concrete or rock, the mine fires as an instantaneous bomb. No self-dis-arming devices are fitted.

Figure 74 – BM 1000 I Mine with AD 104 Unit

Figure 75b – BM 1000 I/II Mine with AB 104 and BV 3