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Shen44
 
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Default Angle of prop shaft - theoretical question

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
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JAXAshby
 
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Default Angle of prop shaft - theoretical question

shen, the "down" component is indeed quite noticeable. In fact, it is the
reason outboard runababouts have the steering wheel on the right side of the
boat.

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








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JAXAshby
 
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Default Angle of prop shaft - theoretical question

They put the helm on the right hand side because the traffic
approaching you from that direction has the right of way, and
it's important that you be able to keep an eye on it.


nah. outboards have had rh turning props since loooooooooooooooooooooooooooong
before the Rules of the Road (originally an east coast yacht club's racing
rules). Ole Evinrude's engines (built in Milwaukee and sold to and for
Midwestern fishermen operating on Midwestern lakes a three or four day train
ride from the east coast) turned clockwise (from the top) because most men are
right handed (and this made it easier to hand start the engine turning cw) and
a cw turning engine could have a cheaper, longer-lived thrust bearing in the
lower unit if the prop turned right, thus lifting the right side of the boat
from the reaction to the torque of the prop. Therefore, the boat operator sat
on the right side of the boat. Still true to this day for outboards.
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