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

Inspired, no doubt, by their countrymen’s pioneering use of the spar torpedo, and bolstered by Russian and French successes in the years since the end of the civil war, the Torpedo Station was still issuing detailed Spar-Torpedo Instructions for the United States Navy as late as 1890. According to these instructions the standard outfit of Service spar torpedoes comprised a set of twenty-four, with twelve for use on board ship and twelve for the ship’s boats.

Each Service spar torpedo measured 12in (30.5cm) long by 9in (22.9cm) square, all inside measurements. They were fabricated from sheet iron tinned inside and out, the inside surfaces being shellacked and the exterior asphalted. The empty case weighed about 15lbs (6.8kg), and the charge was equivalent to 34lbs (15.4kg) of dry gun-cotton, including the primer. The latter was fired by electricity, rubber grommets being arranged in the top of the case. Exercise torpedoes were also available, slightly longer than the Service type but only a third of the width and depth, and shellacked inside and outside. The Exercise torpedo weighed 3lbs (1.4kg) and its charge of dry gun-cotton added another 4lbs (1.8kg). The firing circuit was to be made up by cutting and connecting suitable lengths of insulated double cable from the 300ft-long (91.4m) reel supplied.

The Service spar torpedo for boat use would be attached to a spar made up of two steel tubes 18ft and 15ft long which telescoped one inside the other with an overlap of 2ft (9.45m total length), held in place in the bow of the boat by a complex system of yokes and gearing, to permit accurate placing of the torpedo. The boat torpedo was to be immersed to a depth of at least 10ft, and could safely be exploded 22ft away horizontally (3m deep by 6.7m distant).

Interestingly, the Service spar torpedoes for ship’s use were to be attached to the ends of 45ft-long (13.7m) wooden spars braced out from the sides of the ship, one on either side of the foremast and one on either side of the mizzen. Ship’s torpedoes were also to be immersed to a depth of at least 10ft, but to ensure the safety of the attacking ship had to be exploded at a distance of at least 35ft (10.7m) from her hull. For the Exercise torpedo, an immersion of 5ft at a range of 20ft was suitable for firing from both a boat and the ship (1.5m depth at 6.1m distance). Instructions were also provided for converting the Service torpedo to a contact exploder, and for constructing improvised spar torpedoes from wooden kegs or casks, caulked on the outside to make them watertight, and charged with black powder.

For its part, the Royal Navy also continued with the spar torpedo up to and beyond the end of the nineteenth century. One design comprised a metal cage enclosing a ring of six TNT cylinders placed around a seventh cylinder, to which was attached an electrical primer and lead to a battery on the launch. Firing was initiated by a pair of contact horns protruding from the head of the torpedo.

The surviving early film sequence shot by Alfred West in around 1898 shows Royal Navy spar torpedo exercises, probably in Fraser Lake, which was part of Portsmouth Harbour. In the full sequence, when the huge water plume has subsided, the steam pinnace setting off the spar torpedo explosion appears unharmed.

^{Discovered in the Solent, a dinner plate, possibly from RN mess № 20 attached to the torpedo school at HMS Vernon, was decorated with a spar torpedo and its successor, a very early Whitehead, but both evidently in use at one and the same time. The Latin inscriptions translate as ‘Great perils lurk’ and ‘Vernon is always strong’.}

THE ‘CROUCHING DRAGONS’

The final manifestation of the spar torpedo concept were the ‘Crouching Dragons’, or ‘Fukuryu’, the weapon of a brave and dedicated group of young men of the Imperial Japanese navy’s Special Service Corps in 1945. As seen in the illustration on the next page, here we have an explosive device on the end of a long pole, intended to sink a vessel by exploding against its underwater hull. To all appearances, this is a classic spar torpedo — and conceived as a desperate last resort against a vastly superior naval power, as was the very first spar torpedo.

Unbelievable as it may sound, these sailors were trained as suicide frogmen, prepared to wade out from the invasion beaches, or hole up in diving chambers hidden off the coast in wrecked ships or underwater caves, in order to thrust their spar torpedo into the hull of an Allied landing craft heading for the shores of Japan.

A surviving Fukuryu trainee, Mr Shimizu Kazuro, was interviewed by a journalist at his home in Nagano prefecture in the course of 2013. He described how conditions for the Japanese in 1945 were becoming desperate. As a young naval trainee of just sixteen he was drafted to the ‘Tokkotai’, the Special Service Corps who made up the kamikaze units. From an initial total of 300 trainees, all firstborn sons, only children, and boys with no father were drafted out, then the trainees thought to be of above-average intelligence were separated and sent away, and the 100 left were the kamikaze recruits.

^{An indistinct still from a very early film, shot by Alfred West in around 1898, showing spar torpedo and mine explosions. The original, one of a six-frame fragment, was attached by West to documents to prove his copyright, and is now held at The National Archives, Kew.}

^{Above: Drawing from the January 1946 report by the Naval Technical Mission to Japan, index no S-91(N): The Fukuryu Special Harbor Defense and Underwater Attack Unit — Tokyo Bay.}

The Crouching Dragons wore rubber diving suits, and breathed recycled air through a simple arrangement using caustic lye. However, if they forgot to breathe in using their nostrils and exhale though the mouth, they could accidentally inhale caustic lye and quickly lose consciousness. Training consisted of jumping from boats and practising descending to their operating depth, and then they would practise walking on the seabed, guided from a boat by an officer pulling on guide ropes. All too often the trainees would be dragged down by their equipment, which out of the water weighed more than they did, or they would mix up their breathing procedure and suffocate, or the defective brazing on the breathing gear would fail and let in water with disastrous results, or they would simply become entangled in weeds and drown.

Mr Kazuro recalled how at least fifty of his comrades died in this appalling manner. There were too many to cremate in a religious ceremony at the local shrine, so their bodies were simply piled on fires lit along the shore.

Reference works often state that the Fukuryu units were disbanded before hostilities ended because of these appalling casualties. But that was not so. After the news of the Hiroshima and Nagasaki atomic bombs, and the emperor’s radio broadcast, the officers ordered all the equipment and documents to be gathered up and burnt. The Fukuryu were to have remained a closely-guarded secret. It was only after many years that the survivors revived the memory of their lost comrades, and arranged for the small commemorative statue to be made and placed in the Yushukan Museum.

^{Below: Next door to the Yasukuni shrine in Japan is the Yushukan Museum of the Heroes. Thanks to the efforts of survivors such as Shimizu Kazuro, a statue was placed in the museum to honour the lost Fukuryu trainees, the ‘human spar torpedoes’, so many of whom lost their lives not in action, but in training.}

THE TOWED TORPEDO

Robert Fulton had conceived the idea of a towed torpedo back in 1804 for the attack on Boulogne, when pairs of large coffers and pairs of hogsheads were towed to where they were left to drift down onto the French ships under the action of wind and tide. When he sank the Dorothea off the Downs in October 1805 he had used the same type of arrangement. He modified this idea in 1807 for the demonstration when he sank the old brig at New York, keeping his charges underwater, suspended from floats. And there the idea rested.