I believe Shen is wrong here Jeff and you are right. The angle of the shaft
would definitely affect propwalk. It's not the only factor but it will
contribute. I think the biggest villain is pitch and rudder placement as
well as flow and entry/exit of the prop wash.

I think there is less propwalk on folding/ feathering props. I carry a
13"x19# LH 3 bladed prop with a stern hung tiller that is the size of a
small barn door. The prop well unfortunately is small and my upper clearance
is only 4". The keel is 5" thick at the shaft and this affects the flow to
the prop and correspondingly to the rudder in reverse.

Wouldn't it be wise in a twin screw configuration to have counter-rotating
props? This would eliminate propwalk altogether. I was coxswain on a Aux CCG
with a pair of matched outboards and counter-rotating props.... I could
station keep that bugger in the worst conditions with no problems.

CM


"Jeff Morris" jeffmo@NoSpam-sv-lokiDOTcom wrote in message
...
| My props are Left-Hand, two blade folding. There is virtually no
propwalk. I'm quite
| familiar with the phenomenon because my old Nonsuch would walk hard to
port, as would all
| the single screw boats I've driven.
|
| I was under the impression that a major contributor to prop walk was the
angle of the
| shaft; thus, if its horizontal, the affect is greatly reduced. If this
isn't the case,
| what does cause it?
|
| -jeff
|
|
|
| "Shen44" wrote in message
| ...
| Subject: Inherently beautiful.
| From: "Jeff Morris" jeffmo@NoSpam-sv-lokiDOTcom
| Date: 10/22/2003 13:00 Pacific Standard Time
| Message-id:
|
| Neal really doesn't understand, even though I explained it fully.
He'll
| figure it out and
| come up with a creative way to cover his ignorance!
|
| BTW, I get virtually no prop walk - is that because the shaft is
horizontal,
| the blades
| are flat, the keel is long, or a combination of all three?
|
|
| None of the three SHOULD eliminate "prop walk", singly or in combination
.....
| G you don't have Kort nozzles, do you?
| To be sure I'm thinking correctly, both your props are right hand,
folding? (I
| have no experience with folding, so I don't know if this may be a
factor).
|
| When backing, your boat, should want to back to port, as Neal said, once
you
| lose steerageway .... does it? (assuming two right hand props ... I
can't
| remember if you said right or left).
|
| Shen
|
|