Comments interspersed: (based on an inboard, right hand prop)

Rod McInnis wrote:
"otnmbrd" wrote in message
nk.net...

G So many people think of "prop walk", or that "swing to port" as
their enemy and sometimes it is, but it can be made to work FOR you,
just as often if not more so.



Backing up a single engine inboard is no where near as easy as the simulator
would suggest. With an I/O or outboard you have some reverse steering at
dead slow speeds, but a full inboard does not.

Generally, but not always so, but you also explain the possibilities later.

When starting forward from a full stop the prop will push water past the
rudder and immediately provide steering thrust. Indeed, you can actually be
making way in reverse, shift to forward and have the rudder respond even
before the vessel has starting making forward motion.

Whenever you "kick" it ahead, from either stopped, or going astern, your
boat will tend to first react to the rudder, then the fwd thrust. This
will be most noticeable when going astern, but also if you start at a
DIW condition .... naturally G the size and type of your rudder will
have an affect on the degree you will notice this.

In reverse, there is very little tendency for the propeller current to flow
across the rudder. Thus, the rudder has almost no effect until has started
moving in reverse fast enough to have the resulting current act against the
rudder. If your rudder is large enough this can overcome the "prop walk"
forces and provide some real steering. On many small inboards, however, you
are unlikely to be moving fast enough in reverse to get adequate rudder
control.

So true .... here, rudder power becomes a factor, and why most never use
the rudder on MOST boats, to steer astern, accept in conjunction with a
"kick" ahead.

Knowing which way the prop walk will swing your stern (it isn't always to
port, and will depend upon which direction your prop turns) may allow you to
plan accordingly and use it to your advantage. For example, if you have the
advantage of approaching a dock so that you bring your port side up, or turn
to starboard to enter a slip, then a "swing to port" prop walk can be an
advantage.

True, or let the prop walk create the swing, as you slow for position.

On the other hand, if you have no choice but to turn left into your slip it
won't do anything for you. If you need to back straight for a distance then
the prop walk is certainly not going to be an advantage.

First part ... I disagree. When making a stbd side too approach, if you
put the boat into a slight left turn as you are making your final
approach for position, or even just coming alongside, prior to moving to
position, then the port prop walk can be used to stop your headway, as
well as your left turn (I use this one frequently and note that it's
effect will vary with type of dock you are approaching).

Second part .... depends on conditions of rudder power, wind direction,
current direction (and speed for both) .... BG course, it won't be a
"straight" back, more like a snake wake with the end results.

Naturally, everything we're talking of here will be highly dependent on
the particular boat, operator, and conditions.

otn

Rod McInnis