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| GERMAN UNDERWATERS ORDNANCE MINES |
| Chapter 5 - AIRCRAFT MINES - SVK |
| THE LM MINES |
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The LMF Mine. The LMF mine development was started with the aid of the experence gained in work on the LMC and LMD developments. LMF was the first and only German operational aircraft-laid, moored, influence mine. Although it was laid operationally from aircraft, most were laid by surface craft. The LMF mine could be modified easily to be suitable for surface-craft laying, in which case the modified assembly was designated LMF/S. |
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The LMF Mine was known to have been used with the following firing units: |
| 1. M 3 |
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2. M 4 |
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The following units, although not difinitely known to have been used in LMF, could have been used: |
| 1. M 2 |
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2. A 7 |
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Description of case: |
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Shape |
Cylindrical, with hemispherical nose and tappered, finned tail |
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Material |
Aluminum (KSS) |
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Diameter |
26 in. |
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Length |
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Over-all |
7 ft. 8 in. |
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Forward section |
3 ft. 6 in. |
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After section |
4 ft. 2 in. |
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After buoyancy |
2 ft. 7 in. |
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chamber |
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Charge |
610 lb. cast hexanite |
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Description of External Fittings. |
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Hydrostatic clock |
6 in. diameter on nose, 11 in. from center, secured by keep ring |
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Detonator
cover |
4 in. diameter, 270° from top center line, 2 ft. 5 in from after end, screwed to case |
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Booster release mechanism |
4 in. diameter, 90° from top center line, 2 ft. 4 in. from after end, secured by keep ring |
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Anchor-securing |
Three, 120° apart 8 in. from center of nose |
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Mooring eye |
On nose, 8 in. from center |
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Suspension lug |
180° from top center line, 10 in. abaft the nose |
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Joining flange |
3 ft. 6 in. abaft the nose, fitted with 36 evenly spaced stud holes; covered by two sections of semicircular sheathing, 2 in wide |
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Anchor-positioning |
Three, 105°, 195°, and 345° respectively from top center of nose |
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Ballast weights |
Six; one on end of each fin; one near end of each lower fin |
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Fins |
Four; 45°, 135°, 225° and 315° from top center line, at after end; 2 ft. 5 in. long, 10 in. wide |
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Figure 63 – LMF Mine Afloat |
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Figure 64 – LMF/S Mine |
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Figure 65 – LMF Mine, Showing M 3 Unit |
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Operation. When the mine is dropped, a safety fork is removed from the booster re-lease mechanism, allowing the booster to house over the detonator. As the mine separa-tes from its anchor, a pin is withdrawn from the hydrostatic clock. The mine then takes depth by a loose-bight hydrostat system. Water pressure depresses the clock spindle at a depth of 15 feet. starting the clock. The clock runs off its delay period, and the firing unit begins its testing cycle. |
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No self-disarming devices are fitted. |
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Figure 66 – Diagram of LMF Mine |
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