Thanks ....comments interspersed:

Rod McInnis wrote:
With this in mind, for those with twin screw boats, if I told you that
rudders were important tools of boat handling, but not to be considered
for steering, rather for "thrust vectoring", when maneuvering around a
dock, etc., when kicking an engine ahead, both positive and negative
...... would you understand what I was saying?



No, I would think that most people would be more confused.

Why?


To begin with, I would start by pointing out that there is a big difference
between how an inboard reacts and how I/Os or outboards react. There is
also a big difference between what I call "large rudder" and "small rudder"
boats.

Sorry, I should have made it more specific that I was just talking about
"inboards" not IO's or outboards. On inboards, there can be "large
rudder" as well as "small rudder" boats (generally they tend toward
"small" but it's "not written in stone"). It's also interesting that few
talk about type of rudder when talking about it's "size" (can also be
read as "power").

A typical sail boat has a "large rudder" which becomes effective, in either
forward or reverse, as soon as the boat is making way.

A typical power boat has a "small rudder" which either needs a significant
amount of boat speed or to have the prop pushing water past it. These
rudders are generally ineffective in reverse.

see above


The basic concept of twin engine inboards is that you consider the rudder to
only be a factor when the engine is in forward. Ignore it for the engine in
reverse.

Interesting comment that I think a few have made. To check on myself, I
went back to my original post to see if I'd indicated anywhere that I
was applying this "thrust vectoring" to astern "kicks" ... I wasn't, and
in fact specifically stated "when kicking an engine ahead", so I don't
know where your last two sentences are coming from.
Hmmmm I see something ... "both positive and negative", refers to rudder
angle when doing, say, a twist or walk.

otn