Phaeton's trials tested funnels, draft, and machinery

Phaeton's earlier full-power run had exposed inadequate natural draught in the stokeholds. Raising the funnels from sixty to sixty-eight feet and increasing the spacing between fire bars then gave the boilers ample steam without relying on forced draught. The machinery developed about 5,575 indicated horsepower and reached 18.64 knots at light draught with comparatively economical coal consumption. A heated expansion gear nevertheless snapped before the planned six hours ended, and the Admiralty later censured officers involved in accepting the engines and removed the chief engineer.