Originally commissioned for the Greek Air Force,[1] the ships were requisitioned by the Admiralty to meet the needs of a scheme to create an African inland navy.

Both Mimi and her sister ship HMS Toutou had a length of 40 feet (12 m) and could travel at up to 19 knots (35 km/h; 22 mph) by virtue of two 100 horsepower (75 kW) petrol engines attached to twin screws.

The launches underwent trials on 8 June 1915, and by the middle of the month were packed aboard a liner destined for Cape Town, South Africa.

At the beginning of July they arrived in South Africa, where the ships were loaded onto a train bound for Elisabethville in the Belgian Congo, and finally the village of Fungurume, where the line ended.

Streams which Spicer-Simson had depended on for navigation turned out to be nearly dry: the ships had to be raised on barrel rafts to float, and even then they had to be portaged dozens of times.

Ignoring orders to stay behind, Wainwright took advantage of Mimi's speed and zoomed ahead to harass the rear of the German ship.

In order to fight back, Hedwig von Wissmann would have to turn around to bring her main guns to bear; when this happened Mimi would dodge away and Fifi could close her range.

[5] Although there were still German vessels on the lake (most notably Graf von Götzen, armed with a formidable gun from the cruiser Königsberg), Spicer-Simson retreated to a cautious strategy, constraining himself to ineffectual support of the land campaign.