tassie....this is a very complex issue, however simplified.......
'the mechanics of the rudder system is such that it could withstand an opposing force of approximately 1/3 of the vessels [weight] displacement....and within these
limits would act as a rudder'
This being [in round figures] a Corvette of ~~1000 tons, and the rudder structure resistance ~~300 tons
So if the Corvette were helmed at speed greater than the
limit, the vessel hull would commence to be pushed sideways without steerage
Fully agree, for greater mechanical reliability, twin rods between the servo and the rudder........during a turn, one rod is in compression & the other in tension & visa versa in the opposite direction........balance of forces
Derek