The ineffectiveness of existing signalling methods in battle – a mixture of flag, semaphore, searchlight and (the least used) wireless – is evident.
Wireless telegraphy – WT – was the latest to be used and could have freed the British from many of the disadvantages of visual signalling but it had its drawbacks. It could be jammed (the Germans did this quite successfully); it sometimes gave away vital information on an enemy’s strength as well, indirectly, on the type of ship (because signal strength was different from small destroyer to battleship); it could be interrupted if the aerials were down (as happened on the Lion in the initial battle-cruiser actions) or if electrical supplies were similarly interrupted; lastly – the matter that most concerned Jellicoe – these signals could be read. It was also not that fast because of the amount of to-ing and fro-ing that went on with getting a signal out.
WT was still pretty much an orphan when it was used at Jutland. It was not even considered a part of signalling and was taught alongside electrical disciplines at the Torpedo School, HMS Vernon, until 1907. From July 1908, signals training incorporated a rudimentary knowledge of WT and it was only from 1914 that it was fully incorporated into the main signals curriculum.
The two flag “failures” (Beatty would not have called them that) that led to the ineffective use of the 5th Battle Squadron at the start of the action and to the near fatal lack of co-ordination at the start of the race to the north highlight some of the issues with flags.
While flags had been part of the navy’s core skills since the Napoleonic Wars and required no “technology”, they were obviously susceptible to visibility conditions, either natural or man-made, such as cordite and funnel smoke. Because signals were a visual method, they had the effect of “bunching” fleets and keeping them from dispersal, particularly disadvantageous to scouting duties. Given that the visual distance between larger ships was around 14 miles this was a short reaction time for fleets converging at a combined rate of 50 knots, as was the case when the Grand Fleet met the High Seas Fleet before the Jutland deployment. This led to quite considerable impact on flagship (hence the name) position in a line of battle. After the 1910 sea trials, the common assumption was that the best position was in the middle so that signals could emanate out, up and down a battle line. The Lion’s signals went no further than the Tiger. She should have passed them on and did not. But flags also took time to distribute commands: to pass a message back along 29 capital ships – the number that would be fighting at Jutland, creating a continuous line of ships almost eight miles long – could take, at worst, half an hour.
Bringing a dreadnought to a full stop took some distance. Shutting off the engines at 15 knots required a mile and a half. In many ways it was with the smaller, more mobile ships – the destroyers – that this problem of control was most keenly felt. Commodore Charles Le Mesurier, commander of the 4th Light-Cruiser Squadron, put it like this:
The lesson of all this long and weary wait has been that you MUST leave things to individual initiative in these very high-speed little ships – there is no time to make signals – and I am very pleased with the way that my few “action” signals were taken in, and acted on.
The other side of this is that Beatty hated the slavishness of which the flag system was in many ways emblematic: commanders losing their sense of personal initiative and needing a signal to tell them what to do.
Beatty used flag signals sparingly but at least imbued in his captains the fact that the movements of the flagship should be their guide.
Searchlight signalling was as fast as flag signalling, and had the advantage of being more readable in low light and bad visibility but like WT was subject to electrical failure and battle damage. Given the lack of initiative and of radar, and the slow speed of flag signalling, Jellicoe probably had no option other than to keep a tight rein on the fleet. His caution over signals security was perhaps imbalanced. He would have profited handsomely had he made the message clear: relaying enemy positions back to the commander during fast-moving actions essentially much outweighed any idea of compromising the sender’s position.
Considering the amount of signals traffic that came from the Iron Duke in the hours of darkness, it was extraordinary that such little intelligence had, by officers of either the Grand Fleet or Beatty’s battle cruisers, been passed back. In fact, according to Harper, between 9.17 pm (when the last flag signal was made by the Iron Duke) and 2.20 am (when it was light enough again for flag signalling), no fewer than 42 WT and 85 lamp signals were sent out.