[C320-list] Autopliot Upgrade

[Graeme Clark]

For what its worth, last year we upgraded to the SPx-5 Raymarine wheel pilot having ruled out a below decks option due to cost - not just the unit but installation cost.
A couple of points to be aware of:

The SPX5 has a yaw sensor in the autopilot computer (which must be mounted on a vertical surface). Ours is below decks on the back of the hatch between the aft cabin and the rear locker space - not ideal but nowhere else to do it that is vertical and athwart ships.

Because of the yaw sensor it is better than the ST4000 but still a bit 'lacking'. You can pre-set a sensitivity level, which is easily adjustable up or down 'on the fly' but the option basically boils down to a jittery sensitive autopilot making constant corrections (with attendant power drain issues) or one that makes fewer corrections but steers a leisurely course.

From your post it seems you have  - like us -  an engine instrument pod mounted beneath the wheel. This didn't prevent jus installing the wheel pilot but the 'pull to stop' handle that projects out of the top of the pod meant we couldn't roatet the wheel pilot so that the motor was in the five o'clock position rather than the 10 o'clock position (looking forward) which are the only two options that the wheel pilot is pre-drilled to accept.

When in the 10 o'clock position the new wheel pilot motor produced a HUGE magnetic interference to the binnacle compass -  well beyond anything that could be compensated.

The solution was to have an electric solenoid stop fitted so the engine turns off when the key is turned to off, just like a car, and then we could remove the pull-to-stop handle and rotate the pilot to get the wheel motor where it didn't cause interference.  (Cost about $300 inc fitting). Then the net problem was that the instrument pod still fouled the clutch lever that enages and disengages the wheel pilot. However we found that we could cut the lever down without materially affecting it's usability. Not ideal but a workable solution.

All in all however i am bald we went for the upgrade. It is streets ahead of the ST4000+ even though on the face of it, it appears to be the same design.

Hope this helps

Graeme, Hull 303, England
On 19 Apr 2013, at 20:01, c320-list-request at lists.catalina320.com wrote:

> ------------------------------
> 
> Message: 2
> Date: Fri, 19 Apr 2013 14:17:57 -0400
> From: Scott Thompson <surprise at thompson87.com>
> To: "Catalina320.org" <C320-List at Catalina320.org>
> Subject: [C320-list] Autopilot upgrade
> Message-ID: <51718A55.1090907 at thompson87.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> 
> Time to replace my old, tired, non-functional autopilot, and possibly 
> other instruments not working at the same time. I'm toying with the idea 
> of switching to a below-decks linear drive instead of the wheel pilot I 
> have now. It would be more powerful than the wheel drive, include rudder 
> sensor, and be more protected from the elements. Also, it would clean up 
> the helm station and would not require moving the engine instruments 
> pod, which otherwise would be necessary with a new wheel drive. The 
> installer I'm talking to says that he would anchor the linear drive to 
> the swim platform, through-bolted with a stainless backing plate (which 
> would thus be on the top of the swim platform).
> 
> Some questions for you...
> 
> 1. Does anyone know whether that part of the swim platform is sold glass 
> or cored? This is on a 1999 model year boat. The installer says he has 
> done similar installations on a 350 and that the swim platform is sturdy 
> enough to take the forces involved. I'm sure that is true for normal 
> sailing but what happens in a hard grounding?
> 
> 2. Thoughts on whether this is a crazy idea? Has anyone else made that 
> change? The only real downside I've discovered is the cost, which is 
> substantially more than a wheel pilot. But I'm tired of dealing with the 
> old ST4000+ which seems to be broken more often than not, and never did 
> steer a straight line at its best, even when I followed all of the 
> tweaks and recommendations coming from this list.
> 
> Scott Thompson
> Catalina 320 "Surprise," hull #653 (1999)
> 

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