"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.

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.

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.

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.

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.

Rod McInnis