There's no need for variable pitch -which is why you don't see it in
mega yacht thrusters


Cheers FT.

DSK wrote:
Bart Senior wrote:

2 points

After hitting the lottery for big bucks, you have nearly completed
your 150' new sailing mega yacht. Included on your new toy are both a
bow and stern thrusters--for side-to-side control..

What sort of prop would you want if you were concerned about precise
speed control, and being able to back down nearly instantaneously?

Money is, of course not a concern.


Hydraulically controlled variable pitch.

BTW is this 150' yacht equipped with a rack of racing dinghies and a
retractable artificial beach?

Fresh Breezes- Doug King

Nav wrote:
There's no need for variable pitch -which is why you don't see it in
mega yacht thrusters


Cheers FT.

I believe the discussion regarded the Main Engine, not the thrusters

otnmbrd wrote:

Nav wrote:

There's no need for variable pitch -which is why you don't see it in
mega yacht thrusters


Cheers FT.


I believe the discussion regarded the Main Engine, not the thrusters

I thought it was 'bout the whole propulksion package 'cos he mentioned
dual thrusters. If just about main engine that's a really boring question.

Cheers

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


Nav wrote
otnmbrd wrote:

Nav wrote:

There's no need for variable pitch -which is why you don't see it in
mega yacht thrusters


Cheers FT.


I believe the discussion regarded the Main Engine, not the thrusters

I thought it was 'bout the whole propulksion package 'cos he mentioned
dual thrusters. If just about main engine that's a really boring question.

Cheers

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