Boilers, turbines, and the hidden cost of warship development

The Royal Navy adopted commercially developed machinery such as higher-pressure small-tube boilers and steam turbines when it became available, making turbine propulsion part of HMS Dreadnought's defining advance. Smaller boiler tubes supported higher pressure, improving both speed and the return obtained from a ship's fuel. Industry carried much of that development expense when it expected enough orders to recover the investment. A modern Type 45 comparison separates the large cost of developing a class from the falling marginal cost of later units and shows how cutting a planned twelve-ship run to six concentrated sunk research costs in fewer hulls. Older programs could therefore appear much cheaper per ship because companies spread development across longer production runs while later units became progressively less expensive.