Torpedo: The Complete History of the World's Most Revolutionary Naval Weapon

The pentad mount weighed 40,970lbs (18.58 tonnes) and the blast shield added a further 1040lbs (472kg). Each barrel was constructed of rolled steel 0.21in (5.33mm) thick, and the inside surface was milled smooth. The guide stud on top of the torpedo body fitted inside a bronze T — guide which was riveted to the top of the tube. The torpedo body was supported on three bronze rollers in the bottom of the tube, for ease of loading and launching. Training was by electric motor driving a hydraulic pump, or in an emergency by handwheels. The torpedo setters sat on top of the tubes, and the mount captain stood on the left, connected by telephone with the torpedo officer at the director on the bridge wing. A simple on-mount sight was available if the torpedo director was out of action.

A retractable crane was used for loading torpedoes into the tubes, but the final effort was by hand, aided by the rollers and a well-greased torpedo. Obviously, this could not be accomplished out at sea or when under fire; in any case, US destroyers did not carry reload torpedoes, and reloading the tubes was always carried out alongside the depot ship or quay. The torpedo would be pushed in until its guide stud engaged with the front stop-latch, after which the rear stop would be lowered, holding the torpedo securely in place. The tripping latch, when set in the ‘down’ position, would start the torpedo engine on launch.

^{Mark 14 and 15 torpedo loading.}

The depth-setter device set the depth for all five torpedoes at the same setting. The gyro setter could set the gyros for all five torpedoes to the same angle, or it could set the angles for a spread, altering the gyro of each of the left-hand and right-hand pairs to divert at the chosen angle from the line of the centre barrel.

Each black powder impulse charge for launching a torpedo was contained in a case 3in diameter × 13in (76mm × 330mm) long. Mark 14 and 15 tubes required a sodium nitrate black powder charge of 38oz (1kg). The primer inside the cartridge was normally fired electrically, or if necessary by percussion. The gases entered an expansion chamber with a flash eliminator, then passed down into the tube to eject the torpedo. On launching, the tension link holding the front stop in position fractured, the stop swung out of the way, and the trip latch started the torpedo engine. It left the tube at a minimum speed of 50ft per second (15m/sec). Barrels were usually fired in the order: left, right, left-centre, right-centre, centre. This order was fixed to balance the tubes as far as possible when training after having fired one or more torpedoes.

To prevent the tubes and the mount from icing up in cold climates, the mount training circle and the rear part of each individual tube were fitted with heating pipes, fed from the destroyer’s auxiliary exhaust steam supply. This enabled the torpedoes to be trained and launched in temperatures as low as 10°F (-12 °C). Overlooked but vital components were the threaded canvas protection covers, which came in a variety of different types, shaped to protect each vital part of the mount exposed to the elements.

^{Pentad mounts, Mark 14 above and Mark 15, with blast shield, below.}

^{The rear tube door resembled those on a submarine, with door lugs which engaged in slots in the tube ring, except that on this version, it was the door itself which revolved to close, not the ring, which was fixed.}

^{A preserved USN DD pentad torpedo tube mount with blast shield fitted to protect the torpedo-men from the blast of the nearby 5in/38 gun mount. Visible are the rungs to gain access to the interior and the front vision slot; the spoon folding extensions have been removed, and the mount lacks the firing chambers. (Photo courtesy of Robert Elder, National Museum of the Pacific War, Fredericksburg)}

^{Below: Before launching, the on-mount controls set the torpedo speed, depth, gyro angle and spread.}

Torpedo director

The Mark 14 and Mark 15 above-water torpedo tube mounts were controlled by the Mark 27 torpedo director. One of these was normally mounted on each bridge wing, and served by four men, the torpedo officer who selected the target and the torpedoes to be launched, the director trainer, who used the telescope to sight and keep onto the target vessel, the selector switch operator, who sent the commands to the torpedo tube mounts, and the telephone talker who was in contact with the mount captains.

Japanese quintuple torpedo tube mounts

^{IJNS Shimakaze (‘Island Wind’), prototype Japanese super-destroyer, the only one fitted with quintuple tubes, showing her fifteen-tube broadside of 24in torpedoes. She carried no reloads. (Drawing by Peter Mickel from Warships of the Imperial Japanese Navy 1869–1945)}

MODERN TORPEDO TUBES

With the need to launch fast-reaction, small antisubmarine torpedoes during the Cold War period, deck-mounted torpedo tubes came back into fashion. The Royal Navy came up with a heavy triple mounting, the STEWS, which in its one-over-two arrangement harked back to their ‘V’ and ‘W’ destroyer mounts.

In an effort to save weight, modern torpedo tubes are fabricated from glass fibre. Training twin and even triple mounts, such as the NATO-standard US Mark 32 can be found on many modern warships. They are calibrated to launch the Mark 46 and Mark 54 12.75in (324mm) diameter anti-submarine torpedoes, or the similar Sting Ray and MU-90.

The latest torpedo tube development is the MLS, or magazine launch system, in which the tube and its torpedoes are mounted within the ship’s structure, protected from the elements. The torpedo is launched athwart the deck via a hinging flap, and is slowed by its attached parachute before hitting the water.

^{The Mark 27 as shown in the instruction manual.}

^{The repeater receiver mounted on the tubes and the dials on the receiver with matching pointers.}

^{A Mark 46 practice torpedo being fired from the Mark 32 triple mount on USS Mustin. Note the tube muzzle covers attached to the tube sides. (US Navy, photo # 070412-N-9851B-007)}

^{A J+S (Canada) demonstration MLS mounting, complete with a catcher net to trap the practice torpedo.}

^{HMS Montrose test-firing a practice Sting Ray torpedo from her MLS. The Sting Ray deploys a parachute to slow its entry into the water. (Photo courtesy of Navy News)}

CHAPTER 12 Underwater Torpedo Tubes on Surface Ships

Above-water tubes posed a danger in that the torpedo warhead, and in the case of the Whitehead type, the air flask, were vulnerable to counter-fire. Explosion of the air flask could wreak havoc on deck; explosion of the warhead could prove fatal. A case in point is the presumed explosion of a loaded tube under American gunfire on board the Spanish armoured cruiser Vizcaya off Santiago on 3 July 1898.

Underwater tubes had the advantage that the torpedo space could be protected by the armoured deck of a protected cruiser. On battleships the mounting was usually positioned well below the waterline and was therefore in theory well-protected from shellfire. Another plus point was that the torpedo was not subject to impact damage on entering the water, and the deep fitting of battleship tubes meant that the effect of surface waves on initial guidance was minimised.