Well what can i say,

My flying starts with PA28's and included the PA 30 with non contra rotating
props and the PA 39 with contra rotating props and goes all the way up to
the L1011 B757 and even the LHD Death Cruiser he he.

The P factor will i suspect actually de power the wind generator sadly i
dont have the time or the motivation to actually sit down and calculate this
- perhaps introducing the P factor into this discussion was not helpful - it
is as you probably fully understand one of 'the results' which is why i did
include it.

All i know is real time actual results. When i was sailing with many of my
friends in the Caribbean they tied off their W/G's when out sailing in
20+knots of wind as they complained of 'problems' in high winds and big
seas. Now they were all on dedicated W/G poles or Radar Arches. Having the
W/G on the mast well you may not notice 'issues' as the mast is supported to
handle sail loadings.

But we have all played with a gyroscope i am sure and we know how hard it is
to move it when it is spinning - put that gyroscope/W/G on the end of a 10
foot pole or even a 30 foot mast and well you are amplifying that effect.
Now put that pole/mast on a sailboat that is moving in a variety of
directions at unpredictibale speeds and rates of change and you are
introducing some serious loads to your W/G mount(s).

I can see a use for wind generators at anchor in anchorages with >10knots
of wind and for sure they work when the sun does not shine - like i
explained i am conflicted as to the CBA vis a vis burning diesel and
purchasing and installing W/G and Solar. I should add i dont have an Amel
nor a generator on board and as we have added more and more electrical loads
we need to seriously look at some means of generating more electricity
'MOSTLY' when we are sailing as the autopilot and all the new electronics
and new 12V freezer (soon new 12V Fridge) and other loads mean that on
passage (only inter island stuff 8 to 16 hours at most) we need to either
run the engine (do some gentle motor sailing) or selectively switch on and
off various bit of kit as well as hand steer for a while something we enjoy
in the heavy weather but not for 8 or more hours. We have a Raymarine E120
plotter and that is too heavy on power consumption for use all the way
through any inter island passage but we have a Raymarine Raynav 320 which
uses much less power so that gets used for power saving navigation. As they
both talk to each other we can share waypoints etc. Obviously the E120 does
much more for us but ATM its power consumption is unsustainable for inter
island passages. I would love a PSA and i am planning to put one on our boat
ASAP my preference would be to use a PMA as a PSA but cant see an easy way
of stopping that charging - sounds like a job for a lead screw to adjust
belt tensioning or diverting that output to a 12V element in the hot water
tank IF or once the batteries are fully charged. Obviously the normal
car/boat style alternator has advantages in a PSA application as you can
simply switch it on and off BUT the down side of that is that to power the
coils and excite the alternator you are going to use 1 amp.

To get back to non contra rotating props :-) i am always amazed and it is
fun to watch and to see the difference in reaction and rotation of twin
W/G's on other boats.

regards

David