Stus-List Autopilot tiller arm on LF38 *without* bolting to quadrant?

Patrick Davin jdavin at gmail.com
Sun Mar 3 22:40:15 EST 2019


I know there was a thread about below-decks autopilots on the Landfall 38
where discussion ended up on "bolt it to the radial drive, reinforcing the
attachment point." (
http://cnc-list.com/pipermail/cnc-list_cnc-list.com/2018-May/200838.html )

I'm researching this now, with interest in installing a Raymarine EV-200
with type 1 mechanical linear drive, and I think it *might* be possible to
do without bolting to the radial drive. Does anyone know if any LF38 has
successfully done this?

I've already read dreuge's post -
http://svjohannarose.blogspot.com/2016/12/below-deck-autopilot.html - which
is excellent. But he went a different route than I want to go, so it would
be helpful to see other photos and installation ideas.

The reason I want to avoid bolting to the radial drive is that Edson has
repeatedly advised against it, calling it a "likely catastrophic failure"
and saying the cast aluminum fixture is not designed for those kind of
torsional forces, it's designed for pulling forces (via the cables). A Type
1 ram has 650 lbs peak thrust and a type 2 has 1050 lbs. Additionally I
have found one account of someone who had their Edson radial explode (with
autopilot mounted to it) - it took 15 years before this happened, but still
not a risk that's worth it in my mind.

The ideas I'm considering for doing this without mounting to the radial
are:

A) custom tiller arm, with a 90 degree bend to clear the radial drive rim.
It would clamp to the rudder shaft in the 1.9" of available space (1.5" of
that is within the bottom concave part of the radial drive). Note I have no
diesel tank under the steering, which makes this easier. I don't have a
design for this idea though.

B) Jefa 270 degree quadrant with integrated tiller arm.
https://www.jefa.com/steering/products/cable/quadrants/quadrants.htm
I'm talking to Jefa (part of PYI now) this week. The quadrant with welded
on tiller arm has less overall height than an Edson radial drive, so it
would fit. But I'm not sure about positioning of the linear drive unit -
it's 27.5" long and the LF38 stern is quite narrow.

Sorry for the long post. The motivation for a below-decks autopilot is that
the wheel pilot is not strong enough for significant wave state (it's only
rated for 16.5k lbs displacement, and the LF38 is more like 19-20k when
loaded for cruising).

-Patrick
1984 C&C LF38
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