Larry,
All helm pump manufacturers equip their helm pumps with non-return valves if
there is additional helm stations and/or an autopilot pump. So, this is the
norm, not the unusual. You would not want the steering wheel to rotate
rather than the rudder move when in autopilot mode. Nor would you want the
wheel on the flybridge to turn the wheel in the wheelhouse rather than the
rudder. That is what they are used for, but they have a secondary effect as
well and that is to prevent the rudder acting like a pump and kicking the
wheel. On sailboats, rudder feedback is a great tool in trimming the sail
plan for rig balance, so you would then want a manual valve where you can
turn on the feature with a lever if in rough water or when using an
autopilot. This is not rocket science. It is common sense. The double pilot
bit is that the non-return capability must be on both of the oil ports of
the pump because either side could be IN and OUT, depending on wheel
rotation.
Steve

"Larry" wrote in message
news:s24ng.2278$Wh.192@trnddc04...
Hello,
I've asked 'the experts' but they must have thought I was asking for
'trade
secrets' and subsequently offered no help.

Here's my problem; I'm installing an Arneson ASD8 Surface Drive in my 30
foot Cobra Terminator race boat and understand I should use a Double
Piloted
Check Valve (DPCV) between the steering cylinder and the helm to eliminate
feedback into the wheel as discussed online at:
http://www.h-ri.com/Product/Steering..._sys_DPCV.html

I'll be using a single station, power hydraulic steering system with a
char-lynn 211-1009-002 helm (recommended for use with the ASD8). I've
been
unable to contact anyone at www.h-ri.com for further details and my
internet
searches (using various related phrases in Google) have been fruitless.

Does anyone here have experience with a Double Piloted Check Valve
installed
in their hydraulic steering system? What manufacturer and part number DPCV
should I be looking at?

You can follow the progress (or lack of progress) on my turbine powered
boat
project online at: www.TurbineFun.com

Thanks (in advance) for your assistance!

Larry