Mark 45 The Mark 45 nuclear torpedo was designed by the United States as a result of the Russian military making technological advances to their submarine weapons. These Russian ships were based on the design of the German U-Boats. They were very noisy boats, which would actually help the United States in the means of detecting these boats. The United States at this time did not have a well-developed weapon for underwater warfare, and this is when the Mark 45 anti-submarine torpedo, a.k.a ASTOR comes into play. The United States started developing the design for the Mark 45 in 1960 and the torpedo was ready to be fired by 1963. The biggest part of the design of the Mark 45 was that a W34 low-yield tactical nuclear warhead, designed to ensure the destruction of the enemy boat by a proximity detonation. To ensure the full control was kept over the release of the nuclear weapon, wire control was added to carry out the detonation. Target guidance signals could also be sent via the wire connection, but ASTOR had no on onboard homing ability. The Mark 45 was 19 inches in diameter, and was launched silently from a standard 21-inch tube by allowing it to swim out. It was 227 inches long and weighed 2400 pounds. Powered by a seawater battery and a 160ehp electric motor, it could reach 40 knots and had a maximum range of 15,000 yards (13,650m), uncomfortably close for any vessel launching a nuclear weapon. In 1976 the Mark 45 was replaced by the Mark 48, which is still the current USN submarine torpedo. The nuclear warheads were removed from the Mark 45’s and a conventional warhead fitted by Westinghouse. These so-called “Freedom” torpedoes were offered for foreign sale without much success.
Developed United States Underwater Nuclear Weapons Weapon Designator Type Range (Yds.) Speed (kts) Warhead MK 14 Mod 3 Torpedo 4,500-9,000 35-50 668lb TPX MK 16 Mod 1-8 Torpedo 11,000 40 960lb TPX MK 27 Torpedo 6,000 40 900lb TPX MK 37 Mod 1, 3 Torpedo 8,000-18,000 Various 330lb HBX-3 MK 45 Torpedo 30,000-40,000 Various Nuclear Capable MK 48 Torpedo 30,000-40,000 Various 800lb HBX-3 MK 48 ADCAP Torpedo 30,000-40,000 Various 800lb HBX-3 SubRoc UUM–44 Rocket 30nm N/A Nuclear Capable UGM 84a/c Anti-ship Missile 75nm 600 488lb WDU18
Why America Developed Nuclear Torpedoes As early as 1917 the Germans had begun to think about new tactics and engineering for new aquatic based weapons. This would all have to start with the redesign of the boats and submarines that the Navy was using at the time. In early August of 1917, the Marine Korps requested several modifications to the design of the new boats in order to make them more effective in Flanders, where the conditions were very different from the Baltic. For example, because of the greater danger of an air attack they requested that the main armament be capable of also serving as an anti-aircraft gun. They would also request that these boats were to have torpedo based weapons incase of an under water attack. The Torpedo Inspectorate would later favor this and the Germans would start looking into underwater warfare weapons that would be of great use, not only for themselves, but for allies that stood with them as well. This would not settle well with the United States, thus giving the United States the ambition to start their own ideas of development for subaquatic weapons for later military use. It was not until the late 1950’s, Soviet nuclear submarines started to appear, and this would be a very serious threat to the United States Navy. After this emergence of these nuclear submarines, the United States would realize that the submarines they have out in the waters now would need to start carrying heavier weaponry to neutralize them effectively. This would call for the United States to start creating nuclear warheads built for under water warfare. There was American interest in a nuclear torpedo as early as 1943, when Captain William S. Parsons, head of the ordinance division of the Manhattan (atomic bomb) project, proposed providing a “gun,” or uranium-type nuclear warhead. So, the Unite States Navy created a torpedo that would be fitted to have a W34 nuclear warhead inside of it. The Navy would also make a trip wire design. This wire is what guided the missile towards its target; it was also the detonating wire that could only be triggered by the firing submarine. The design of this torpedo was finally finished in 1960, and there were approximately 600 torpedoes that were created between the years of 1963 and 1976. This underwater nuclear weapon would be called the Mark 45 a.k.a ASTOR. Also, in 1960, the United States also declared the use of nuclear warheads to be placed in the first operational supersonic bomber that was the Delta winged B-58 Hustler. This aircraft would be used to drop nuclear warheads over the points of target detected by the sonar systems in use at the time. However, when talking about the Mark 45, the United States would eventually declare this weapon to be too dangerous, because of the torpedo’s extensive blast radius and the damage that it would attribute to the targeted ship, so, the United States would proceed to take the W34 out of the torpedoes. The Mark 48 would be the new device that was built and is still used by the United States Navy to this day.
United States Torpedoes Following the Nuclear Mark 45. The Mark 45 was one of the most unique underwater weapons that the United States had developed. After realizing the power of this weapon, the United States decided to stop the production of these weapons and started the production of the Mark 48 torpedo. The United States took the nuclear warhead out of the Mark 48 and started using this weapon as their primary weapon for underwater warfare. The United States believed that the range of the Mark 48, along with the accuracy was more effective than the nuclear torpedoes. The Mark 48 is 21 inches (533 mm) in diameter, has a length of just over 19 feet (5.8 m), and carries a warhead of approximately 650 pounds (295 kg) of high explosives. The weapon is estimated to have a speed of 55 knots and a range of 35,000 yards (32 km). This is a very powerful weapon to try to harness, so, the United States Navy designed a guidance wire that spins out simultaneously from the submarine and the torpedo. This enables the submarine to control the “fish” using the larger and more capable passive sonar of the submarine. The wire is then cut and the torpedo’s homing sonar seeks out the target. As emphasized earlier, while it streamed a wire to the submarine after being launched, it’s gyro placed it on the bearing to the target. The wire only came into play if the target’s position and movement suggested a change was needed to correct the torpedo’s gyro course. In such case, the fire control technician made the alteration through the wire. This engineering was introduced in 1972 as the ultimate submarine torpedo, replacing the Mark 45 and 37 before it. The United States would go on to make advances to the Mark 48. The U.S. would create a Mark 48 Mod 3, which made advances to the homing system. The biggest design was that of the TELECOM system, which would provide two-way data transmissions between the submarine and the torpedo, enabling the torpedo to transmit acoustic data back to the submarine. Later upgrades have attempted to overcome the challenges presented by high performance Soviet submarines. Over 5,000 Mark 48 torpedoes were produced in several mods and remains to this day as the standard anti-submarine weapon launched from a submarine. This design would be the final design that the United States Navy would make to their subaquatic torpedoes.
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