In way of stressing something otn is saying.
The major component of thrust for any angle of prop rotation is aft/back.
The components for up, down, to the right, to the left, are small.
Keep in mind that when we are saying up, down, right or left, we are not saying
straight up,down,left or right, but simply modifying the straight back
component ....slightly.
When going ahead, for most boats, the hull will never really feel or be
impacted by that "up" component, for the simple reason that it's up angle will
not reach the hull, prior to it clearing the stern.
When going astern, the same thing applies. The water is not be so much directed
"UP" or "Into" the hull, as it is being directed along the hull and quickly
clear of the hull, which allows for the same decreased efficiency of the 090 -
270 arc of the rotation in reverse (RH prop).
Steve, I think otn's response basically covered what I would have generally
said in my response to your last post to me, so I'll let his stand.

Shen