Raymarine Autohelm ST7000 Installation Instructions Manual page 15

Power Pack Selection (Constant Running)
Hydraulic power pack selection depends on the
vessels overall length and the displacement of the
steering cylinder.
Using figure 2 establish the target hardover time
for your vessel. This is combined with the
steering cylinder displacement in figure 3 to select
the appropriate hydraulic power pack.
10
Note: If power packs other than the Autohelm
models are used with the ST7000 the following
solenoid specifications must comply-
Pull in Voltage - less than 8V (16v for 24v
systems)
Drop out Voltage - greater than 2V
Operating Current - less than 5A
The Solenoid Voltage must be the same as the
course computer.