[C38] Autopilot installation

[Ray Torok]

Hi Max,

Not sure if this will help, but a couple of years ago I installed a below
deck autopilot system.

This turned into a big job.  I suppose I got carried away.  Most people
probably would not go to this much trouble or be okay paying  someone to do
it.  However, I would note that it worked great on a trip from San
Francisco to La Paz and back.  We also replaced the old Raymarine control
head with a Pelagic.  The old system simply could not control the boat when
sailing downwind with quartering seas.  The new system drives the boat
better than most people.

I wanted to install a below deck actuator for a couple of reasons:

·         Bypass the steering cables to eliminate the slop introduced by
the cable linkage and stretch (the old system used a motor/toothed gear
assembly mounted on the pedestal)

·         Have backup steering in case a cable breaks

The main problems were:

·         Limited space for the actuator

·         Not enough space on the rudder post to install a small tiller arm
above or below the quadrant (really a 360 degree disk in this boat). *If
you don’t have that problem, the whole project gets much easier.*

·         The quadrant is not strong enough to take the load that the
actuator can generate if there is simply a bolted attachment (Edson warns
not to attach a ram to the quadrant).

I ended up designing and building a set of aluminum rings that bolt onto
the quadrant to distribute the load imparted by the ram.  At the same time
I installed hard rudder stops that a block mounted on the upper ring
engages to limit rudder travel and prevent the ram from overrunning its
range.  I also installed a rudder position sensor that the control head
uses to limit rudder travel when the autopilot is engaged, so it never
tries to drive the rudder against the hard stop.

I ended up with a Lecomble & Schmitt hydraulic actuator, because it was the
only one I found that would fit in the space available, as the pump and
actuator were separate units connected by hoses.  Longer electric units
would extend into the cockpit locker and appeared much more difficult to
mount. The static end of the actuator is bolted to an aluminum channel that
is bolted to the underside of the cockpit sole behind the pedestal. I put
the pump at the aft end of the cockpit locker, with the actuator just
behind the adjacent partial bulkhead.  I also cut a large hatch into the
floor of the cockpit locker to get better access to both the engine and the
quadrant area.

Selected photos are attached.  I would be happy to discuss any of this
further if that might help.

Good luck,

Ray  #38 Thira



On Mon, Aug 10, 2020 at 1:10 PM Max soto <maxsoto at gmail.com> wrote:

>
> Hi everybody,
>  It’s been nine years since we were in this subject.
> I’m going to make a second attempt to install a below deck unit. Will like
> something stronger than the wheelpilot.
> I assume/hope that someone might have installed one In this years. If so,
> please send pics and tips.
> I already have a Raymarine linear drIve type 1 ready to be installed. Hope
> I can make it fit somehow.
>
> Regards,
> Max Soto A.
> +506-8312-1367
> C38 Estancia #198
> _______________________________________________
> Listserve mailing list
> Listserve at catalina38.org
> http://catalina38.org/mailman/listinfo/listserve_catalina38.org
>
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