I have used tiller Auto pilot for two decades.
When motoring in calm seas any tiller pilot will do.
When going down wind in moderate to heavy seas the tiller pilot has to react
fast to correct it course.
The type of keel will affect the behaviour of the tiller pilot. If you have
a long keel and it will require more power than a fin keel in a following
sea and up wind.
The trimming of your sails will affect the behaviour of the tiller pilot.
Not to mention the weather helm of your boat. Other factors are the current,
wind and tides
My suggestion is if you intend to use your boat in all but the heaviest seas
buy the one that has a fast reaction time with the maximum push and pull
power (143-187 lbs). If the reaction time of your tiller pilot is not fast
enough it will get you off course and it will always work too hard to get
back on course. Tiller pilot are exposed to the element and do stop
operating when under stress and high humidity. That why I carry the old one
as a back up.

"Courtney Thomas" wrote in message
ink.net...
Looking at the stats on... for example the Simrad Tiller Pilots
10,20,30...
I see that the thrust difference between
the least and most capable is 44 lbs., which is a 24% variation from least
to most [143-187].

The Simrad recommendation on boat length is from 33 - 39 feet, and
displacement from 8140 - 14000 lbs.

My question is:
given the above, is the real-world difference for a typical
35'-40' sailboat that one pilot will simply
'do it' faster than the lower powered, OR will the 143 lbs
of thrust not do the job but the 187 will...
according to Simrad's specs ?

I do assume there is some length/displacement combinations for which
Simrad's specifications would be strictly true,
of course, but..... as a real-world matter, what experience have group
members found applicable ?

Appreciatively,

Courtney