Robert Whitehead was a thorough engineer, capable of taking a problem and working on it relentlessly until he had hammered out a solution. That he did not continue to develop Luppis’s idea of the Küstenbrander is therefore intriguing.
Later engineers took up the idea, as we have seen in the previous chapter, and made it work. Whitehead could have replaced the ‘clockwork’ power source by a compressed air motor, as he fitted to his prototype torpedo. But as a highly visible surface-runner that would have been vulnerable to gunfire from the target vessel, and a one-inch Nordenfelt round could certainly pierce the air flask wall.
He could have explored the float torpedo option, using flotation devices such as Fulton had employed to sink the brig at New York. Filling the float with cork would have rendered it virtually unsinkable. The float torpedo configuration would also have furnished him with his desired aim of striking the target not on its armoured waterline, but at its most vulnerable spot, the underwater hull.
The continuous controllability was another aspect he discarded. It is likely that Luppis’s arrangement of tiller ropes added drag and complication. They also risked entangling the propeller. Piano wire could have been a viable alternative, as later used by Brennan.
It is probable that the single most compelling reason why he discarded the notion of the Küstenbrander was the invisibility aspect. If he could succeed in making an underwater explosive device travel in the direction he sent it, and if it would continue to keep to the depth he selected to do the most harm to the target, then the invisibility/surprise factor would seem to take priority. After all, it was the very opposite of the brave but extremely hazardous spar torpedo which was making the news in the 1860s.
In fact, what Whitehead did was not to continue to develop an existing idea, but to take a great leap forward, with the results we know so well. The Whitehead story has already been described in great detail by the late Edwyn Gray, so here we will only examine the salient features in the unfolding of the saga.
A photo Gray included in his book on Whitehead, The Devil’s Device, wondering if it showed Whitehead with the lost prototype, is almost certainly of something completely different (see Chapter 21 for details). No authenticated photo of the 1866 prototype has come down to us, and this is perhaps indicative of Whitehead’s thoroughness. He was a hard-headed businessman, not a romantic. Why preserve as a cherished memento a primitive version when the next model was so superior?
The prototype Whitehead built and tested in 1866 is known only from eyewitness descriptions. It was said to have a blunt nose like a dolphin, with fins extending for virtually the entire length of the body. It is evident that the onlookers were kept at a considerable distance. A more detailed and probably more accurate description is given by Fregattenkapitän Theodor Braun in the November 1935 issue of Marine-Rundschau magazine:
‘The “Torpedo” was made of steel sheets with a length of 3.4m (11ft 1¾in), a diameter of 0.36m (14in) and a weight of 136kg (300lbs).Two vertical fins extended from this diameter a further 25mm (1in) upwards and downwards, joining at the stern and leaving a cutout for a two-bladed propeller, with a vertical rudder that could be fixed. In the centre of the body there were two guide strakes also extending 25mm beyond the full diameter. The internal layout was kept secret from the inspecting committee. The nose contained a simple percussion detonator, followed by the payload of 8kg (17.6lbs) of gun cotton. The next section contained the ‘depth control’ consisting of a plate responding to water pressure and an arrangement for transmitting the plate’s movements via simple external wires to a pair of fins.’
Braun also reported that the prototype was set in motion inside a ‘launching cage’ suspended beneath an anchored boat, hence the need for the guide strakes. The two-cylinder engine was driven by compressed air at a pressure of 370psi through a regulating valve to ensure a constant speed, which was around 6.5 knots over a distance of 200yds; it then travelled on for another 100yds at a lower speed. It is clear that Whitehead was still thinking at this stage of a close-range coastal weapon to defend harbours and anchorages.
Azimuth control was achieved by means of a preset rudder mounted behind the propeller, regulated after trial and error on the Fiume range. This procedure would be retained for decades as a means of testing and then adjusting each individual torpedo over the many years of its active service life. Depth control was by a hydrostatic pressure valve acting on horizontal tail planes, and on the first model this was extremely erratic. The eyewitness account of its resemblance to a dolphin was perhaps derived from the prototype’s behaviour as much as its appearance.
In the drawing reproduced in Braun’s article, all the features of the 1866 prototype are present, plus a pair of horizontal stabilisers fitted on either side of the nose. In addition, the two-bladed propeller is enclosed in a shroud. However, the device shown behind the warhead is clearly the pendulum, regulating the hydrostatic valve fitted amidships, so it is probable that this drawing shows the revised prototype of 1868 incorporating Whitehead’s ‘Secret’. Movement of the depth-keeping gear appears to be transmitted via external horizontal wires to the tail planes, via rocking levers. These small planes are fitted in front of the propeller shroud. Probably the horizontal stabilisers were fitted to the nose while Whitehead mastered the adjustment of the pendulum. The vertical rudder appears to be braced by diagonal wires to the propeller shroud, and lengthening or shortening these wires would give the required steerage.
A photograph from Count Hoyos’s collection shows an early Whitehead torpedo (displayed inverted), and today we can find this very same torpedo mounted on the wall in the Vienna Military Museum.
Contrary to the plan drawing, the Vienna torpedo now has a three-bladed propeller, similar to other early Whiteheads with shrouded propellers in the Split maritime museum. The adjustable vertical rudder which would be fastened to the propeller shroud is missing, as are the movable horizontal tail planes. The external control wires to the tail are not present, but the central horizontal strakes are there. What appears to be a sliding regulator set in the top part of the vertical fin also corresponds precisely with the drawing. The long exploder is missing from the nose, but the four holes, two either side of the nose, are clearly the positions of the attachments for the bow stabilisers. This in fact could be the relic of the second prototype of 1868, because no other Whitehead has been seen with these fixed bow planes.
Note the considerable keel surface offered by the rearward extensions of the top and bottom fins, aiding directional stability. It was likely that with the slow speed of the prototypes, the torque rolling moment from their single propeller was not excessive, and the vertical strakes could control it. After all, slow-speed full-size ships with only one propeller do not suffer noticeably from torque rolling. When the torpedo speed was upped considerably, it would become necessary to fit the contra-rotating propeller arrangement.