How operating assumptions changed the steam-versus-diesel result

A critic challenges the fuel prices and machinery costs used to compare marine steam and diesel plants. The tables assume coal at 20 shillings a ton and oil at 80 shillings, prices he disputes as a worldwide average, while using a higher diesel cost than the paper's own stated average. He also argues for 240 or 250 days at sea instead of 200, which would improve the diesel result. His port-consumption comparison gives about 36 tons a year for a diesel cargo ship with electric auxiliaries against 400 to 500 tons for a steamer. Higher economical speed could attract shippers and improve the prospect of a full cargo. Shipowners' construction programmes are offered as evidence of their preference after operating different machinery types. The criticism also recalls earlier exaggerated claims for diesel, so misleading assumptions are not treated as a problem confined to steam advocates.