systems can be installed with a bypass to the check valves if you want both features. At a minimum I recommend using a good helm pump
with integral check valves (usually the balls in the check valves can be removed later if you desire to have continuous feedback) and a bypass valve. The bypass valve is handy when you are cleaning
the bottom and want to move the rudder
whilst in the water
It is a myth that there is no feedback with the checkvalves installed. Think about it. The force required to move the rudder
is a function of the number of turns of the wheel
to get lock-to-lock of the rudder, the radius of the wheel
, and the force you apply to the radius of the wheel with your arm. It is impossible to turn the rudder without feeling the force required. The more water
force against the rudder the more power it takes either by an autopilot
or your body to quickly move that rudder, hence you HAVE feedback.
I used to have the check valve bypass on another boat
. I did not use it because it was so much easier to turn the wheel to trim the boat
heading, take my hand off the wheel and not have the boat turn due to any residual weather
or lee helm or a turbulence in the water against the rudder. This is a nice feature that most sailboaters are afraid of because of this myth that one cannot have feedback with hydraulics per se, or check valves in particular. Such people probably have not had much experience with a good hydraulic installation
. Anyway, I converted my present boat to hydraulic steering to eliminate the backlash or give that cable steering systems all have (if you attempt to remove the backlash then you wind
up with a very stiff friction-full wheel response) and to provide a platform amenable to installing a real autopiliot.
Make sure that you plan carefully the geometry of the hydraulic ram, the ram "tiller" arm, and the ram size. The ram attachment to the hull
must be VERY robust to be reliable. If you use the new Teleflex prefabricated hydraulic lines and their hydraulic fittings you will have the best chance of having zero leaks
due to their design using "O" rings in addition to the normal sealing features of the usual fittings. In addition, the lines are much easier to install without kinking than copper tubing.
Do not be afraid of mixing brands of hydraulic gear
: you might opt for a variable ratio helm pump
by Kobelt, a hydraulic expansion tank by Hynautics, hydraulic ram by Capilano or Hynautics (or Kobelt), tubing by Teleflex and autopilot
, for example.
Start by picking a ram that is strong enough, and more, for your rudder. That establishes the ram volume (you will use only a balanced cylinder). That volume then establishes the helm pump volume. Calculate that you need to have a turns ratio between 3 to one and 5 to one (max for a sailboat in my opinion) and, therefore, a 13 cubic inch displacement
ram requires a helm pump displacement
of 13/3 cubic inches per turn for a 3 to one turns ratio which equals 4.33 cubic inches. An adjustable helm pump that has 2.6 to 4.33 inches per turn (or a range wider than this) will give you the ability to set between 3 and 5 turns lock to lock. Similarly, a calculation will establish the autopilot pump size and speed. Figure that for offshore work
steering downwind in a heavy following sea that sufficient power is needed to turn lock-to-lock in about 7 seconds, depending upon your boat response to the rudder angle.
Keep in mind that most autopilot recommendations are made for vessels in relatively tame conditions and, therefore, are too slow for serious offshore work
under all conditions. Note that when conditions are bad that is when you DON'T want to have to steer. You will get tired fast and will probably be busy doing other things.