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| BRITISH EXPLOSIVE ORDNANCE |
| Part 1 - Chapter 8 |
| Antisubmarine Bombs |
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A.S. 500-lb. Mks I - IV (Obsolescent) |
| Data |
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Fuzing |
Mks I - III, Nose Fuze No. 32; Mk IV, Tail Pistol No. 28 or No. 30 |
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Color markings |
Dark green over-all; ½-in. red band 1 in. from nose; 1-in. light green band 6 in. from nose |
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Tail No. |
Mk IV - No. 9 Mk I |
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Over-all length |
Mks I and II, 74.0 in.; |
| Mk III, 76.0 in; | |
| Mk IV, 72.5 in. | |
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Body length |
Mks I, II and III, 53 in.; Mk IV, 50 in. |
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Body diameter |
Mks I and II, 14.0 in.; Mks III and IV, 14.3 in. |
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Wall thickness |
Mks I and II, 0.16 in. |
| Mks III and IV, 0.18 in. | |
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Tail length |
Mk IV, 24.2 in. |
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Tail width |
Mk IV, 14 in. |
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Total weight |
Mk IV, 490 lb. |
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Charge/weight ratio |
Mk III, 62 - 64% |
| Mk IV, 58% |
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Body Construction: The Mk IV body conssists of a hollow nose forging or casting, and a cast or forged tail adapter, welded to a sheet-steel casing. The nose is threaded to take a solid nose plug, which is secured by a locking screw. The casting is made in two parts, welded together longitudinally. The tail adapter receives the exploder contai-ner, which is locked and sealed in position, and houses the detonator holder and pistol. |
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The Mks I - III bodies have the nose of the bomb fitted with an adapter for a nose fuze. Internal strengthening bands are welded to the body, which has no tail adapter. A ballistic cap screws on the nose to prevent ricochet. |
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Tail Construction: The Tail Assembly No. 9 Mk I consists of a sheet-metall cone with a cylindrical strut attached to it by four fins. The assembly is secured to the tail adapter by four spring clips on the cone. A reach rod, with arming vanes attached to the after end, extends through the cone and engages the arming fork of the tail pistol. |
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The tails of the Bombs Mks I - III consists of a cylindrical strut attached by four fins to a dome-shaped tail cone, and secured to the body by a central bolt. |
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Suspension: The bomb is horizontally suspended, by a single lug, secured by screws projecting through the case and into a steel-block support pad welded to the interior of the body. |
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Explosive Components |
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Detonator – (See Part 2, chap. 4, Detonators.) |
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Exploders – C.E. pellets. (Early bombs had C.E. and TNT.) |
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Filling – Mk IV, 282 lb. TNT, or may be filled with RDX/TNT (when RDX/TNT is used, bomb has ½-in. nose topping and 1-in. base topping of TNT); Mk III, 291 lb. TNT or 308 lb. Baratol 10/90. |
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Remarks: These bombs are designed to give maximum blast effect for use against submarines. The Tail Pistol No. 30 with a needle striker is to be used in the Bombs Mk IV A/S bombing. The Tail Pistol No. 28 can be used in place of the No. 30 for land bombard-ment. |
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Figure 32 – A.S. 500-lb. Bomb Mk IV |
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