Boiler and turbine supply choices

The class specification called for White-Forster boilers, although USS Portland ultimately received Yarrow boilers. Portland's boilers fed Parsons reduction-geared steam turbines and still formed a capable machinery plant. The discussion contrasts the British Parsons lineage with the American Curtis side of the Brown-Curtis turbine relationship. The difference between the specified and installed equipment shows how machinery supply could shape the final form of a warship.