The engines would be 325 hp Elders compound engines. These would have to be able to develop 1,300 effective hp. Two cylindrical boilers with 6 furnaces each would have to be able to handle 60 pound steam pressure. The space taken by the engine was also limited by the contract. All in all the engines and boilers should give the ship a speed of 10 knots with a coal consumption of 23-25 tons. The trial run would have to reach 11 knots. The specification was signed on account of John Elder by Ch.J. Viehoff. The company could deviate somewhat from this contract, especially on account of the depth of the Suez Canal. The prospectus of 14 March 1870 announced somewhat larger ships than required. The ships would be of 2,000 tons cargo space and 400 nominal horse power, 1,600 ihp in order to ensure a more regular service.