The SS City of Cairo on which Frank was travelling had arrived in Gibralter on 27 June 1940 with members of the 82nd Heavy Anti Aircraft regiment on board.  The ship was owned by the Ellerman Hall Line and was a cargo ship of 8034 tons.  It had cabin accommodation for 150 persons which on the voyage from Gibralter was taken up by 134 civilian refugees and 6 officers.  The diary of the 53rd HAA Regiment describes the SS City of Cairo as much more comfortable than the SS Alma Dawson on which they had escaped from Marseilles.

When they left Gibralter on 2 July 1940 the journey back to England was estimated at 12 days, which was slower than expected but caused by the slow speed of the other ships in the convoy.

The 53rd HAA Regiment diary for 3 July 1940 states:

Mileage of day 120 moderate seas.

The Unit diary for the 157th HAA Battery for 3 July 1940 states:

At sea - ships Standing Orders received.

The deck space reserved for the 157th HAA Battery was the Poop and the Poop Deck at the back of the ship.