Battle of Jutland

During the First World War, the Battle of Jutland, fought between the British and German navies, was the largest naval engagement of the war, and stayed the largest battle between ships until the 1944 Battle of Leyte Gulf. Ultimately, it was inconclusive. The Germans destroyed more British ships, and considered it a tactical victory, while the British, because the German High Seas Fleet never again operated as a unit, regarded it as a strategic victory.

In many respects, both sides thought they were deceiving and trapping the other, although it is fair to say that the fog of war was very heavy for Germany and Britain. Various sub-units were not aggressive enough when the tactical situation warranted it, while others were too aggressive for their capabilities and took heavy casualties.

Both sides had an overall tactical commander, but with a key subordinate leading heavy scouting forces:

• Reinhard von Scheer, commanding the German High Seas Fleet
  • Franz von Hipper, commanding a scouting and "bait" task force
• John Jellicoe, commanding the British Grand Fleet
  • David Beatty, leading fast forces

German plans

Germany began the action, as a part of the more aggressive strategy introduced when von Scheer replaced Admiral Hugo von Pohl in February 1916, as chief of the German High Seas Fleet. Scheer ordered a major force, under von Hipper, to cruise along the Danish coast, covered by the alert High Seas Fleet.

British response

Royal Navy Admiral John Jellicoe, commanding the British Grand Fleet, received reports and indeed ordered his forces to sortie. Jellicoe misinterpreted signals intelligence reporting on the developing German action. knew a little too much detail about SIGINT without fully understanding it. He asked the analysts where call sign "DK" was located . DK was the headquarters of the German High Seas Fleet, under Scheer. The analysts answered his question precisely, telling him that it was "in the Jade River". Unfortunately, Jellicoe did not know that the Scheer used a different identifier when at sea. Jellicoe assumed the German fleet was also in the Jade River, so held back on committing all his forces. When he found out the true situation, he lost faith in SIGINT, not accepting that it was his own error.

Jellicoe's faith in cryptographic intelligence was also shaken by a decrypted report that placed the German cruiser Regensburg near him, during the Battle of Jutland. It turned out that the navigator on the Ravensburg was off by 10 nmi in his position calculation. During Jutland, there was limited use of direction finding on fleet vessels, but most information came from shore stations.