Subject: Inherently beautiful.
From: "Capt. Mooron"


"Shen44" wrote in message
| I, Like otn, do not agree with the angled shaft creating all that
noticeable a
| difference in "prop walk".

I wonder if "sucking" wash at an angle may reduce the effect of the rudder.
I don't believe the angle affects the walk by itself.... only influences the
wash over the rudder.

BG This may be part of the problem you are having with otn's comments.
Generally, when we discuss prop walk, we relate it to backing, not ahead
motions of the prop. Prop walk, when going ahead, is there and useful or
harmful, depending, but not as noticeable or well used as when going
astern.(which also means we may be trying to make totally different points)
I'm not sure what you mean by "sucking wash" regarding the effects of and on
the rudder?
The angle of the shaft, may well affect the wash across the rudder and how it
responds, but I would assume (right or wrong) that that may be accounted for by
some of the "tear drop" shapes you see in some rudders....only a guess.

| Although I may agree that a prop tunnel, may act similiar to a Kort
nozzle, for
| an open prop, I don't think the prop wash behind a wide keel, when going
astern
| will have a noticeable affect on prop walk.

Don't the newer cruise ships now use pod screws for better control and
performance? That would be like a prop in reverse ... sort of.

Azipods (was on one last weekend) They are more like a outboard drive that can
turn 360 deg (electric motor in the pod) independantly of each other .... kind
of like Z-drives on a tug. Yes, make for a highly maneuverable ship.


Shen