A WW2 vet gave my son a few books..

[razark]

Originally Posted by mookiemookie

Indeed. The Fleet Type Submarine manual gave instructions on how to take a proper prop count in order to determine speed.

It, along with these other first person accounts, make it pretty clear that prop count was indeed used to assess target speed regardless of what third person researchers think.

The sonar stack also included electronics to make it easier to get the prop count. They must have meant for it to be used somehow.

Do any of the sources mention how accurate the speed obtained was?