Turbine blades as a warship-building bottleneck

What is the hardest single component to make for a dreadnought battleship?

The answer picks turbine blades: they require exact metallurgy and precision engineering, and failure in a geared-turbine system can cripple the ship's propulsion.

Main turrets are difficult assemblies, but the answer singles out turbine blades as the most demanding individual component. Their performance relies on precise metallurgy and manufacture, especially in geared-turbine machinery. A failure there directly threatens propulsion, illustrating why naval industrial capacity is more than the ability to assemble a hull and guns.