Hydraulic Steering & Bypass Valves

Posted by katorpus (katorpus@…>)

A “pure” hydraulic steering system has a completely dead feel to it.
Due to the check valves, the rudder provides no “feedback” to the
helm and you don’t experience “weather helm” at all…Move wheel,
rudder moves. Stop moving wheel, rudder stops. No feel.

I’ve sailed on a (early 80’s) Nauticat with this arrangement. I
hated it. Trimming sails to hold your course includes looking back
over the transom to see how much drag your rudder is adding to the
equation, because you can’t feel it. You OUGHT to be able to trim a
boat to sail in a straight line “hands off” (in moderate seas and
winds, anyway). With this installation, you just CAN’T tell when the
rudder is adding drag. This may be ok for power boats, but for
sailing, it just plain sux.

Enter the “feedback” device. (My Freedom has it…as part of the
Hynautics all-hydraulic steering…I assume most, if not all
Freedoms were built this way.) Pressure against the rudder creates
pressure against the helm…“feel” returns (as long as there’s
adequate hydraulic fluid and the system is properly bled…BUT…

The downside of this is when you add an electric pump into the
equation (for autopilot). Unless the bypass valve is actuated,
the “least resistance” comes from the movement of the wheel. Pump
actuates, wheel moves, rudder doesn’t…not good. The bypass valve
doesn’t bypass the pump, it bypasses the feedback to the helm.

You can still override the autopilot with the wheel (or kill the
autopilot and steer manually with the valves closed), but what you
hear is a godawful grinding type of noise. This is the sound of
the “popoffs” (spring loaded balls in the system) in the helm
reacting to the overpressure situation that results from the bypass
being closed. Hynautics assures me that this is not harmful, but it
sure is annoying.

The “sequence” is, therefore…when steering by autopilot, close the
bypass valves (I have two…manually operated…inside the starboard
lazarette). Engage autopilot. When you go back to hand steering,
open lazarette and switch the valves back. I’ve thought of
converting them to electric (most of which can be moved manually as
well), but that’s just one more damn thing to have to fix.

Posted by mike_c_f35ck (mike_c_f35ck@…>)

Hi,
What do you do when you have to quickly override the autopilot in
case of an emergency? Duck your head in the lazarette first and then
alter course by hand? If that is so, it seems a rather unsafe setup.

Mike


— In freedomyachts2003@yahoogroups.com, “katorpus” <katorpus@y…>
wrote:

A “pure” hydraulic steering system has a completely dead feel to
it.
Due to the check valves, the rudder provides no “feedback” to the
helm and you don’t experience “weather helm” at all…Move wheel,
rudder moves. Stop moving wheel, rudder stops. No feel.

I’ve sailed on a (early 80’s) Nauticat with this arrangement. I
hated it. Trimming sails to hold your course includes looking back
over the transom to see how much drag your rudder is adding to the
equation, because you can’t feel it. You OUGHT to be able to trim a
boat to sail in a straight line “hands off” (in moderate seas and
winds, anyway). With this installation, you just CAN’T tell when
the
rudder is adding drag. This may be ok for power boats, but for
sailing, it just plain sux.

Enter the “feedback” device. (My Freedom has it…as part of the
Hynautics all-hydraulic steering…I assume most, if not all
Freedoms were built this way.) Pressure against the rudder creates
pressure against the helm…“feel” returns (as long as there’s
adequate hydraulic fluid and the system is properly bled…BUT…

The downside of this is when you add an electric pump into the
equation (for autopilot). Unless the bypass valve is actuated,
the “least resistance” comes from the movement of the wheel. Pump
actuates, wheel moves, rudder doesn’t…not good. The bypass valve
doesn’t bypass the pump, it bypasses the feedback to the helm.

You can still override the autopilot with the wheel (or kill the
autopilot and steer manually with the valves closed), but what you
hear is a godawful grinding type of noise. This is the sound of
the “popoffs” (spring loaded balls in the system) in the helm
reacting to the overpressure situation that results from the bypass
being closed. Hynautics assures me that this is not harmful, but it
sure is annoying.

The “sequence” is, therefore…when steering by autopilot, close
the
bypass valves (I have two…manually operated…inside the
starboard
lazarette). Engage autopilot. When you go back to hand steering,
open lazarette and switch the valves back. I’ve thought of
converting them to electric (most of which can be moved manually as
well), but that’s just one more damn thing to have to fix.

Posted by katorpus (katorpus@…>)

— In freedomyachts2003@yahoogroups.com, “mike_c_f35ck”
<mike_c_f35ck@y…> wrote:

Hi,
What do you do when you have to quickly override the autopilot in
case of an emergency? Duck your head in the lazarette first and
then
alter course by hand? If that is so, it seems a rather unsafe
setup.

Mike

NO. The wheel will still override the autopilot. If you change
course with the wheel and do nothing to the autopilot, it will, of
course, try to get back to the original course when you release the
wheel (and moan, groan and complain as you override it). This is
avoided by disengaging the autopilot with the control pad button on
the autopilot (or one of the “satellite buttons” which will also
turn it on or off). If you aren’t on the helm at this point, it’s
just the same as “letting go of the wheel”. No different than any
other autopilot function (except that you don’t “strip” anything in
the process of doing this).

The position of the bypass valves does not alter the function of the
helm (insofar as steering is concerned). In a hydraulic steering
system, the wheel is connected (via axle and chain sprocket) to
a “manual hydraulic pump” which pressurizes the system and extends
or retracts the hydraulic ram connected (outboard) to the barn door
rudder. This continues to work regardless of bypass valve position.
It just makes a lot of noise and does away with the feedback to the
helm to do so with the valves in the “wrong” position.