This information was transmitted to the secondary torpedo control positions installed near the ship’s side, above the underwater tubes port and starboard. Each secondary control position was connected to the torpedo flat beneath it by voice tubes, and by telephone to the ship’s main conning tower and the torpedo control tower. The control tower was connected to the gunnery computer in the transmitting station, and if the control tower was put out of action, the Royal Marines manning the transmitting station could take over and transmit the necessary information to the secondary control positions.
Torpedoes from the forward submerged tubes were launched from either the main conning tower or the relevant secondary torpedo-control position. The torpedoes in the aft tubes, however, were launched by the team in the torpedo control tower. The torpedo-men at the tubes received the necessary gyro angles, speed and depth settings, and the order to launch, from Barr & Stroud repeater instruments. For use in night actions, all the instruments in the conning tower, torpedo control tower and the secondary control positions were fitted with shaded lamp holders fixed so as to illuminate the instrument dials.
To control her two underwater tubes as well as her fixed above-water tubes, HMS Hood was fitted with three torpedo control towers, one aft overlooking ‘X’ turret, and one on either side beneath the midships searchlight tower between the funnels.
On Nelson and Rodney, the last British dreadnoughts to be fitted with underwater torpedo tubes, the torpedo control towers were installed one either side in front of the funnel. These small hooded rangefinders are easily overlooked when studying battleships. It was ironic that this elaborate system produced no confirmed results at Jutland, where many dreadnoughts on both sides launched a large number of torpedoes without scoring any hits.
FRENCH DESIGNS
Henri IV was a small low-freeboard monitor-type of coast defence battleship, with two novel features: her aft superfiring turret, the first to appear on a warship, and her convex internal anti-torpedo bulkhead. The integrity of the latter was, however, somewhat compromised by the fact that her two underwater torpedo tubes pierced the bulkhead protection.
In the accompanying plan, the bottom cutaway drawing, of the tube in plan view, shows the large curved bar or spoon (cuillère) which extended out in front of the torpedo to protect it during the launch sequence. Also evident is the substantial vertically-operating sluice gate which closed off the outboard end of the tube. Unlike later German dreadnought designs, there was no outer flap. A slight resistance to water flow from the open port ends was accepted for the sake of simplicity.
Unlike later underwater tubes, these French designs did not split lengthwise to load. The torpedo flat had therefore to be arranged to allow end-loading, which was achieved by simply offsetting the opposing tubes one in front of the other.
AUSTRIAN DESIGNS
Robert Whitehead had produced the very first underwater torpedo tube in 1866 for the Austrian trials of his new weapon. Subsequently, the Austro-Hungarian navy had adopted underwater tubes in line with all other navies of the period.
US NAVY DESIGNS
Less extreme than her contemporary, the torpedo ram USS Alarm, the Intrepid nevertheless exhibited several novel features. Her hull was especially strengthened for ramming, and a torpedo launching tube was inserted in the centre of the ram, obviously inspired by HMS Polyphemus. Compared to the latter, however, Intrepid was an uninspired design, capable only of a lumbering 10 knots maximum speed — far too slow to catch any ship worth ramming. Plans to strip her of her armour belt and send her to China as a river gunboat came to naught, and she was scrapped in 1892.
For the underwater tubes of US battleships, Bliss-Leavitt designed a special short torpedo, the 21in Mark 3 Mod 1, with a length of 196in (5.4m).
Prior to the Great War, the US Navy Design Bureau of Construction and Repair undertook a series of design studies into alternative forms of dreadnought capital ships. The sketch designs show the barest of details, and if these ships had been constructed, they would have been fitted out with the normal complement of masts and boats. They all did, however, present a minimalist appearance, offering low-profile targets. The design team came up with several interesting alternatives, rather on the lines of a car manufacturer’s ‘concept’ vehicles. Two overriding notions were the desire for high speed, and the reduction of the heavy gun armament in favour of extremely powerful batteries of underwater torpedo tubes.
The heavy torpedo armament proposed in these four concept vessels shows how far torpedo development had progressed, as it was clear that the torpedo was to be the principal armament of at least three of the four. In this respect, the third design was by far the most extreme.
In the event, no battlecruisers would ever be completed for the US Navy, the two giants laid down at the end of the Great War, Saratoga and Lexington, being converted as the world’s largest aircraft carriers. And the 12in-gunned Alaska-class ships produced during the Second World War, although having the characteristics of battlecruisers, and being designed as a response to imagined Japanese vessels of this type, were in reality super-heavy cruisers.