I have no intention adding 'nutty slack' to this but, assuming I'm the other forum member, my explanation of ventilation was merely a simplified version. Prop wash (or walk if you prefer) is factual. Again simplified, dependant on the hand of the prop in question, I.E. a r/hand prop will walk towards the port and vice versa, the effect going forward will be minimal due to the rudder being in the direct flow zone. However, in reverse is a whole other issue! A r/hand prop running in reverse will drag the stern to the right and no amount of tiller swinging will make the slightest difference as the steerable flow is busy rushing under the flat hull. Steerage = a big fat zero, hence most modern 50'+ modern boats having 'girly' buttons (or bow thrusters if you prefer their technical name). A prime example is the 24'er in my avatar, an arse to steer forward with a full water tank and a 15 stone bloke stood on the rear port comer due to the stern design and lack of ballast, in reverse... You're guess is as good as mine, that all depends on a slight breeze, where you stand, what phase the moon is in in Sagittarius! The ballast is one of my first jobs to fix on it.
I hope I've not poked the hornets nest too much?!
Lee.