Some information about German Uboats aka Submarines helping the Ottoman Empire.
The Constantinople flotilla (U-Halbflottille Konstantinopel), also known as the U-boats of the Mediterranean Division in Constantinople" (U-Boote der Mittelmeerdivision in Konstantinopel), was an Imperial German Navy formation set up during World War I to prosecute the U-boat campaign against Allied shipping in the Mediterranean and the Black Sea in support of Germany’s ally, the Ottoman Empire.
- Operating mostly against Russian shipping in the Black Sea.
- Had a maximum strength of 11 U–boats , and some sorces indicate 14 U-boats served in the Constantinople Flotilla (six 6 were lost operationally).
In 1917 the force was amalgamated with the Pola Flotilla, coming under the command of the U-Boat Leader, Mediterranean (Führer der U-boote im Mittelmeer); and the unit was renamed the Constantinople Half-Flotilla (U-Halbflotille Konstantinopel). In 1918, with the collapse of the Central Powers, the U-boats were scuttled, or fled to join the Pola boats in their evacuation to Germany.
Ottomans had no submarines operating in Ww1 apart from a cpatured French Submarine called the Mustecip Onbasi. But the Ottoman Empire ordered 4 Submarines before WW1 2 from the British and 2 from the French until the orders were cancelled with Ottoman entry into the war. Ottomans planned to buy some German submarines and destroyers during and after the war but that proved abortive as both of them lost the war.
Not having submarines actually proved diastrous especially in the Gallipoli campaign but the Turks were not sitting ducks the use of mines, planes for spotting submarines along with coastal artillery fire helped the Turks fight off the submarines of both the British and the French. The German Uboats also helped protect Ottoman ship supply lines to Cannakale.