H.M.S. Polyphemus (1881)
HMS Polyphemus was an experimental torpedo ram of the Royal Navy. Laid down at the Royal Chatham Dockyard in 1878, the iron vessel was partially submersible and intended to attack by stealth. With a top speed of 17.8 kts, she was fast by the standards of the day, though her power to catch enemy battleships was never put to the test. She represented the Royal Navy's burning interest in the Whitehead locomotive torpedo, carrying five 14" launching tubes and a complement of 18 torpedoes, allowing several reloads per attack. Her most visually arresting feature, besides the bulging ballast tanks, was her murderous spur ram, which contained one bow torpedo tube (seen above with a wreath incongruously attached for the vessel's launch in June 1881.) Tactically, this is an acknowledgment of the likelihood of failure in torpedo attack. Torpedoes of the day had a range between 400 and 800 yards (870m) at 21 kts, but were undergoing exhaustive testing and improvement. By 1889 Whitehead's 18" model boasted performance of 1,000 yards or 910m @ 22 kts., carrying an enlarged warhead of guncotton. Even at this rate, to launch a torpedo attack Polyphemus would need to approach within ramming distance of her target anyway.
The Admiralty had set up a Torpedo Committee in 1872 to examine ways in which the newly invented (1866) Whitehead torpedo could be launched at sea. The Royal Navy's first purpose-built torpedo launching ship was HMS Vesuvius which, with a maximum speed of less than 10 knots, was intended to stealthily approach within a few hundred yards of enemy ships at night to launch her torpedos. In the mid-1870s, Barnaby and his assistant J. Dunn developed plans for a fast, cigar-shaped vessel, protected by 2 inches of armour on the deck, carrying five submerged torpedo tubes. The design was modified in late 1875 into a larger vessel equipped with a ram. Early in 1876 the design was modified again into a 240 ft long unarmoured torpedo ram with a top speed of 17 knots. Later the design was modified yet again to have armour added to the exposed steel deck.>
The ship had a cast iron keel which could be unbolted and dropped for emergency buoyancy. The bridge deck and aft flying bridge were also detachable and could float away as rafts should the ship's hull be sunk. The Polyphemus had an 80-volt electric lighting plant -- the first in the Royal Navy.
The innovative, but strange Polyphemus was an experimental ship. She pioneered the underwater beam torpedo tube for the British Navy (she had four). She was capable of voyaging from Plymouth to Gibraltar, or from Gibraltar to Malta at 10 kts without refueling. She proved here worth in the Berhaven raid, an exercise in 1885 meant to simulate a sneak atack on the Russian fleet base at Kronstadt. In the night exercise, Polyphemus penetrated elaborate net and boom defenses. Later she was stationed at Malta and practiced maneuvers with the Mediterranean fleet; but being highly invested in battleship artillery, the spit-and-polish admirals of her day found little use for her; and two sister-ships which had been ordered were canceled. As it happened, the development of quick-firing intermediate guns made Polyphemus obsolescent by the end of the decade. Technology evolved towards smaller, lower-cost, more agile vessels to deliver torpedoes: TBs and destroyers, and later the submarine, which Polyphemus anticipated in many ways. The ship was sold for scrap in 1903.
Polyphemus Plans & Specifications
Specifications for the Polyphemus:
Dimensions: 240' x 37' x 20'6" Displacement: 2,640 tons. Speed: 17.8 knots. Armament: (5) 14" torpedo tubes, 18 Whitehead Mark II torpedoes. (6) 1" Nordenfelt machine guns. Wrought-iron ram. Armor: Deck - 3" compound armour; hatches - 4"; conning tower - 8". Propulsion: coal-fired boilers, horizontal compound engines, twin screw. Crew: 80.
Metric Specifications:
Dimensions: 73m x 11m x 6.25m Displacement: 2,640 tons. Speed: 32.99 km/hr. Armament: (5) 356 mm torpedo tubes, 18 Whitehead Mark II torpedoes. (6) 25 mm Nordenfelt machine guns. Wrought-iron ram. Armor: Deck - 76 mm compound armour; hatches - 102 mm; conning tower - 203 mm. Propulsion: coal-fired boilers, horizontal compound engines, twin screw. Crew: 80.
Polyphemus Photo Gallery
Polyphemus coming into port after a day's maneuvers with the Fleet.
Polyphemus -- stern quarter shot at Malta.
1:1200 Model of the Polyphemus. When the ship was "flooded down" for offensive operations by filling her ballast tanks, the waist section ran nearly awash. Six machine guns were mounted in pillboxes on the flying deck, on the outboard ends of the three bridges.
Polyphemus under construction at the Royal Chatham Dockyard. This view shows the ship's bizarrely shaped ram, the result of elaborate tests in the towing tank.
Closeup of Polyphemus' ram in drydock; it contained her bow topedo tube. Twin rudders under the bow were to assist in steering when backing off after a ramming attack; also improved the ship's turning radius.
The Whitehead Torpedo - Invented 1866
An early model Whitehead torpedo, dating from the 1870s. Whitehead and his imitators used the tapered form until around 1906, when tests proved that the now-familiar blunt-nosed shape (grey form at rear) actually caused less friction and made for a full knot's faster passage through the water: by 1912 the adoption was complete. Whitehead torpedoes were driven by compressed-air motors; other models used flywheel technology and electric motors.
By the mid-1890s the Whitehead torpedo had developed into this elongated form, but retained the conical, pointed tip. Their accuracy in aim and guidance dates to 1895, when Whitehead purchased the patent to the gyroscope from Ludwig Obry, the Austrian navy officer who had invented it. Using the improved gyroscope for azimuth control proved a breakthrough. This system could guide torpedoes up to 7,000 yards -- a range they had achieved by around 1909.
The preferred form of torpedo delivery in the pre-dreadnought era: the torpedo boat (TB). Here is USS Cushing, named for the Civil War hero who first sank an enemy by torpedo attack. Built by Herreshoff, she is seen after completing a test run on the waters off Newport, R.I.
The TB was soon to be eclipsed by the larger and more survivable destroyer. By the time of WWI, however, the ideal platform for the torpedo became the submarine, its technology quietly perfected on the very eve of that dreadful conflict. Ironically, one of the destroyer's main duties then became anti-submarine warfare -- a task for which the type proved well suited. Above, a WWI era German torpedo. Around 1906, tests proved that the blunt nosed form shown above actually caused less friction than the pointed shape, and made for a full knot's faster passage through the water with the same thrust. By 1912 the adoption of the blunt-nosed model was complete.