On our 25' displacement
type boat (6 knots) there is a Raymarine
SPX-5 Sport Pilot installed.
The boat is equipped with a hydraulic steering
I installed it last year, which was straight forward&easy, it works quite well, basically everything is OK.
I am sure you know the SPX-5 Sport Pilot
. There is the the course computer with integrated gyro or so, there is a fluxgate compass
, there is the control unit, and there is an electric motor
that turns the wheel
Additionally I do have a rudder
position transducer that is not necessary but improves accuracy a lot, especially on slower boats.
Now, I'd like to replace the electric
drive unit, which turns the wheel
, by a hydraulic pump, as on a "normal" bigger autopilot
The Raymarine manuals
say that the bigger (and of course more expensive) SPX-10 corepack is necessary when using a hydraulic pump.
I found out that the main restriction of the SPX-5 is that the output current
of the corepack is limited to 10 Amps (for the electric helm
I have an hydraulic pump that would be absolutely sufficent for the size of our boat and the size of the rudder
. It is a 100W pump, thus would draw nominally some 8.5 Amps. The manufacturer told me, the draw under normal conditions is as low as 4 to 5 Amps.
So from that point of view the SPX-5 corepack should be able to handle this.
Of course, I also asked Raymarine. They said, I need the bigger corepack, because the SPX-5 software
is not designed to handle a hydraulic drive.
Now, I wonder what this could mean: To my understanding the computer gets its information from the gyro, the fluxgate
, and the rudder indicator, plus the GPS
when turned on. How the hell should it know that the rudder is turned by an electric drive or by a hydraulic pump?
I am familiar with the needs of the hydraulic installation
(check valve and so forth).
Apart from the higher output for the drive the "bigger" corepacks provide a "clutch" output, which is needed for disengaging a linear drive
or in case a mechanic steering
is installed, which is not in my case. I have a hydraulic steering
, I don't need the clutch
Am I overlooking anything important, or might I try to replace the electric helm
drive by a hydraulic pump?
What are your opinions?