At 05:00 on 23 April 1918, the High Seas Fleet left harbor with the intention of intercepting one of the heavily escorted convoys. Wireless radio traffic was kept to a minimum to prevent the British from learning of the operation. At 05:10 on 24 April, "Moltke" suffered machinery failure: the starboard propeller had fallen off the shaft, and before the turbine could be stopped, a gear wheel was destroyed. The destroyed wheel flung pieces of steel into an auxiliary condenser, which flooded the engine room and stopped the operation of the center and starboard engines. Saltwater entered the boilers, reducing the ship's speed to a mere four knots; by 08:45, the captain of "Moltke" reported to Scheer that his ship was "out of control", and that the ship would need to be towed. At 09:38, the cruiser "Strassburg" attempted to take the ship under tow, but was unable to do so. At 10:13, the dreadnought was detached from the battle fleet to tow "Moltke" back to port. At 14:10, the convoy had still not yet been located, and so Scheer turned the High Seas Fleet back towards German waters. By 17:10, "Moltke"s engines had been repaired, and the ship was able to steam at a speed of 17 knots. At 19:37, the British submarine spotted the ship and fired a torpedo into "Moltke". The ship took in 1,800 tons of water, but was able to reach harbor under her own power. Repairs were carried out in Wilhelmshaven in the Imperial Dockyard, between 30 April and 9 September 1918.