How 850 psi machinery would change the Nelson design

How would 850 psi boilers available to Britain in 1920 change the Nelson design?

The estimated result is an F3-style ship capable of about 28 knots.

Giving Britain 850 psi boilers in 1920 would move the Nelson design toward an F3-style ship. The estimated result is a Nelson capable of about 28 knots. British work on high-pressure marine boilers had begun much earlier: a date around the beginning of the First World War is accepted for an early 600 psi boiler test.