naval offensive To solve the raiding nuisance and to capture the northern, colonised region of the German colony, the British devised a plan for a two-pronged invasion. IEF "B" of in two brigades, would carry out an amphibious landing at Tanga on 2 November 1914, to capture the city and gain control the Indian Ocean terminus of the Usambara Railway. In the Kilimanjaro area, IEF "C" of in one brigade would advance from British East Africa on Neu-Moshi on 3 November 1914, to the western terminus of the railroad (see Battle of Kilimanjaro). After capturing Tanga, IEF "B" would rapidly move north-west, join IEF "C" and mop up the remaining German forces. Although outnumbered Tanga and Longido, the Schutztruppe under Vorbeck prevailed. In the East Africa volume of the British official history (1941), Charles Hordern described the events as one of "the most notable failures in British military history". Only two British regiments were involved in the East African campaign. The 2nd Battalion, Loyal North Lancashire Regiment arrived with the Indian Army invasion force at Tanga and after this stayed on the border between British and German East Africa. The 25th (Frontiersmen) Battalion, Royal Fusiliers was raised for service in East Africa in early 1915 and served throughout the war. In addition, white contingents were supplied by Rhodesia in 1914-15, the 2nd Rhodesia Regiment, Nyasaland and South Africa including the South African Expeditionary Force which arrived in February 1916. Königsberg of the Imperial German Navy was in the Indian Ocean when war was declared. In the Battle of Zanzibar, Königsberg sank the old protected cruiser in Zanzibar harbour and then retired into the Rufiji River delta. After being cornered by warships of the British Cape Squadron, including an old pre-dreadnought battleship, two shallow-draught monitors with guns were brought from England and demolished the cruiser on 11 July 1915. The British salvaged and used six guns from Pegasus, which became known as the Peggy guns; the crew of Königsberg and the main battery guns were taken over by the Schutztruppe and were used until the end of hostilities. Lake Tanganyika expedition The Germans had controlled the lake since the outbreak of the war, with three armed steamers and two unarmed motor boats. In 1915, two British motorboats, HMS Mimi and Toutou each armed with a 3-pounder and a Maxim gun, were transported by land to the British shore of Lake Tanganyika.