"Her boilers were modified to burn only fuel oil as part of ongoing experiments and, on 1904, "vitally important" comparative trials were carried out near the Isle of Wight with "Spiteful"s sister ship "Peterel" burning coal, in which "Spiteful" performed significantly better.Problems with the production of smoke were surmounted so that using oil produced no more smoke than coal, and it was found that the ship's crew could be reduced, since fewer were required in the boiler rooms.