N1EE wrote:
The larger the vessel the more difficult it is to
manuever and stop.

I wanted to be clear the issue in this question
was with respect to backing down. The thrustors
provide good side-to-side control and eliminate
that factor from the question. Could it have
be written more clearly?

The variable pitch allows the throttle to be
set and forgotten while pitch controls linear
thrust--magnitude and direction.

There are no worries about engine stalling while
changing gears, or cables jamming or snapping,
all of which have happened to me in the past, and
each of which could be bad news docking and
manuevering a mega yacht.

Bart Senior


It's not quite that simple.
First off, thrusters quickly lose their efficiency, as soon as you start
moving ahead/astern. You need to keep your speed (generally) below 4K
through the water to maintain good thruster power.
Since it's difficult to make a prop that is really efficient, with a
simple flat blade, most variable pitch will tend to walk to some degree,
at all settings .... good news is it's always the same direction. Also,
especially with use, most variable pitch will pick up a tendency to
"creep" either ahead or astern when the settings are at zero pitch, so
you end up having to "tinker" with the controls.
Overall, I have a Love/Hate relationship with variable pitch. In some
cases I'm damn glad I had it, while in others, damn glad I didn't.
Naturally, if it's the one system you are using, many of the minor
drawbacks will become second nature for you to use or avoid.

otn