When HMHS Britannic was sinking and the screw propeller emerged from the water, at what rpm did it spin?

Note that the Britannic had twin screws controlled independently. Two lifeboats were lowered into the water but were dragged into one of the the spinning propellers and destroyed. This apparently after the engines had been ordered to stop! The captain (Bartlett) then ordered the propellers to be deactivated, and presumably that is the way they stayed while the ship sank.
So the answer is, zero rpm.
https://en.wikipedia.org/wiki/HMHS_Britannic#Construction
titanicandco.com/britannic.html no longer exists

all three ships of the class had three propellers the outboard were tied to recip engines the center to a turbine.

in the confusion after striking the mine the Cpt. tried to beach her. Two lifeboats launched without orders and according to the Brit. Ency. these were destroyed by the propellers. Surely they must have been turning to destroy the lifeboats.

if I had read two paragraphs down the Cpt. heard of the two lifeboats being chopped up and deactivated the propellers. still does not say what rpm .