I served on board the USS Carl Vinson in the Reactor Controls division. We had a knotmeter mounted in the No.2 (aft) EOS (enclosed operating station) Where the watch officer, reactor operator, two throttlemen, and a log-rcorder stood watch. I remember seeing 100% power aft and in the 90's forward: (The aft plant always drew more power at high speed due to the center screws taking more power). At this max allowed peacetime power the ship did do over thirty knots, (but not much)the increase in power required to gain even a few knots was immense. Even if the battle short switches were on (over-riding all reactor protective functions) the plants just plain could not make enough power to go a whole lot faster. The power required to turn a marine propeller is proportional to the cube of the propeller's rotational speed: i.e, to double the speed of the propeller takes eight times the power.

Forty knots? Not likely...