my promblems setting up an Autopilot to my 10foot tube tender was the
compass.
the ractions of the compass where to worse to use it.
The semiregide inflatable with 40HP Johnsen is rigged with a hydraulik
steering system and the hydraulik pump works fine.
when the boot hurts in the sea my small compass ist circeling and the
fluxgate of the autopilot do not deliver usefull data sets.
The Autopilot ill tried was a small DANAHELM unit the first fluxgate has
aircoils and the second was oil filled. The idear adapting NMEA Data from a
GPS Handheld could work but the time to patch the software of the autopilot
to get it work would be to long for me.

Michael from Germany




"BruceM" schrieb im Newsbeitrag
...
Sorry I don't know the construction history of "drunkboat" but I'm sure
that
everything is still as it was when constructed. The problem is not so much
with the auto pilot as it is to do with the jet.
Have you ever let a high pressure hose go seen how it goes back & forth?
The effect on the last foot of hose is determined on the direction the
hose
was pointing milliseconds before, not where it's pointing now.
The effect on the boat is IDENTICAL to what happens to the hose. Of course
steering by hand you tend to anticipate the "direction of thrust" & can
counteract BEFORE it happens. (if you are on the ball)
The auto pilot only reacts after it is determined that it is offcourse &
also off by a certain amount off course. In other words, much too late.
There might be a brand that can be set with quicker react time or
something,
but I'm not sure.
I guess after all is said & done that if you got given one for Chrissy,
then
I'd still put it on your boat. Just don't expect it to go "as the crow
flies" as us Aussies say.
BruceM


"Larry" wrote in message
. ..
On Sat, 29 Nov 2003 19:31:07 +1030, BruceM wrote:

I would say it is impractable.
Chap has an auto-pilot here in Sth Aust on a 38footer and believe me
it
is
the worst boat in the fleet. The boat has the nickname of "drunkboat".
Firstly, those jets are OK for 18 footers going like a bat-out-of-hell
up a
fast flowing river & doing spin-outs in their own length like in NZ
tourist
fjiords.
At 18 to 25 knots they just wander all over the place. Maybe if you
had
a
full length keel or something it might help.
"drunkboat" has nearly been spun that many times in a big following
sea
that
most won't go out with him if there are more than a metre seas
running.
Like
I said, on a 45MPH boat on a fresh water lake.......... no worries.
BruceM

A few years ago I was on a short cruise in a 44' mv in Bermuda. It was
equipped with an autopilot - a Raymarine, I think. We were in fairly
light
seas, but it handled really well. (the Capt. let me take the wheel for
a
while) Of course since there wasn't much of a sea, that might have been
the reason.

My very limited understanding of autopilots is that they have to be
matched
to the boat. The critical parameter is something I'd call "damping" -
how
much rudder is applied for a given deviation and how much rudder
behavior
is anticipated. Another factor might be whether the reference is a
fluxgate compass or a NEMA stream from a GPS.

Do you know much about the "drunkboat"? Was it a do-it-yourself or
professional installation? What equipment?

As I said earlier, this might be a futile exercise - it appears that
nobody
has even tried it.

I don't tend towards going like a bat out of hell! If I lived closer to
a
large body of water, I'd probably have a nice sailboat in the 30 - 40'
range, but they don't trailer very well among the lakes, which, as I
said,
can be shallow...

Thanks for your comments
--

Larry
email is rapp at lmr dot com