Shortly after arriving on Lake Tanganyika, Spicer-Simson relocated his base just south of Lukuga at Kalemie, where he had been building a port better protected from the lake's storms. "Mimi" and "Toutou" were assembled and launched just before Christmas 1915. Early in the morning of 26 December, the armed German tug "Kingani" was spotted offshore. Spicer-Simson took "Mimi" and "Toutou" out on the lake and captured "Kingani" after a brief firefight that killed her commander and four of her crew. "Kingani" was rechristened and brought under Spicer-Simson's command. As a result, on 3 January 1916, he was promoted from lieutenant commander to commander; the promotion backdated to 26 December 1915, the date of the capture.