"John" wrote in message
oups.com...

GBM wrote:
I am still trying to decide on a windlass for our boat. Perhaps some the
experienced cruisers can help?

Our alternator output, is nominally 55A, but likely actually quite a bit
less. Max size alternator recommended for Yanmar 2QM15 engine is about
80A)

I would echo the comments made by others here- get a decent sized
windlass and put in heavy-duty wiring. It's expensive, but just part of
the 'hidden cost' of windlass installations.
I've got a Lewmar Concept windass with an 80A breaker, but I'm sure it
never draws anything like that current in practice. Usual anchor is a
35#CQR with 5/16 chain for the first 175 ft, then rope. Alternator is
55A Hitachi, battery banks supply about 300Ah or so. When using the
windlass, we run the engine and parallel the battery banks- probably
overkill.
Wiring (this is important) is 1/0 tinned marine cable with swaged-on
lugs. My marine electrical advisor (Paul Thornton of Oakville, ON)
insisted on this over my objections, and he was right. Boat is 30ft
sloop, batteries aft.

John,
Your example perhaps explains the reason for my question.

You are right - If I go to a windlass that draws 80 - 90A, I WOULD need
large cables.

Wiring size comment: I doubt windlass wiring really needs to be sized for
3% drop, but if this is desired, your wire size is probably about right. At
10% drop the wire size could be 2AWG which I would think would suffice. If
the engine is running, voltage will be higher anyway, so voltage drop should
not be a major issue (Out of interest, how did you conclude that your
advisor was right about the 1/0 wire?)

Getting back to windlass choice: Why choose a windlass that draws such a
high current on a 30-32 ft boat? There are windlasses available that use
epicyclic (planetary) gears that are much more efficient.

For example, a Quick Genius (similar specs to Concept 1) draws just 40A at
working load - Quick recommends 6AWG wire for a 50-60ft return trip. See:
http://www.1stopmarineshop.com/Quick%20Windlass.html . The Lofrans Dorado
has similar lower current draw. http://www.lofrans.it/english/intro.html
There are vertical units that are also efficient. Is there a downside to
using one of the higher efficiency units?

Regarding adding to battery power: I could use a dedicated battery, but
can't see the point of mounting this forward, especially with a combiner.
After raising the anchor, surely the battery could be quite low and draw
most or all of the alternator output. Can't see how Andina Maries' 10ga wire
would handle a long run carrying say 50 -80A from the alternator unless the
combiner limits the current (longer recharge time)

I think one of my main concerns has been answered - If I draw 80A for 5-10
min, I will not deplete my house batteries very much and even with my low
output alternator, they will recover if I run motor for a short while. If I
chose a high efficiency unit that draws just 40A, I will be even better off
electrically, and its seems will not have to sacrifice much in pulling
power?

Thanks for the input!

GBM