Typically the tiller pilots never had them; if you think about it, if you have tiller steering, you don’t have a quadrant to attach the transducer to. And the older wheelpilots just used a fluxgate compass to steer to. But the results weren’t always as good as they could be, so the ST4000+ added the transducer (which has pretty much always been a part of the below-deck pilot installations) to improve its performance, particularly downwind (which is problematic for many pilots).
The new Raymarine EVO pilot systems still use the transducer; but Raymarine says it’s “recommended”, not necessary. According to the EV install manual: > The connection of a rudder reference unit is highly recommended, to help > ensure optimum autopilot performance... > > Certain environmental conditions such as a cross-current can cause the > autopilot system to steer persistently to port or starboard, even when the > rudder is centered. With a rudder reference unit connected to your autopilot > system, you can use an autopilot control head to specify an offset angle in > +/– degrees to compensate for inaccurate rudder angle information caused by > such conditions. > > The more accurate the rudder angle information, the more accurately the > autopilot system can keep to a correct course. And for Pete Shelquist, even Garmin offers it as an option: > Add Even More Peace of Mind > Add an optional GRF 10 rudder feedback sensor and you can further enhance the > performance of your GHP Reactor autopilot with SmartPump. :^) — Fred Fred Street -- Minneapolis S/V Oceanis (1979 C&C Landfall 38) -- on the hard in Bayfield, WI :^( > On Oct 11, 2015, at 11:06 AM, Rick Brass via CnC-List <[email protected]> > wrote: > > From all the comments over the past few years I know that David’s comment is > true. But I have always wondered “WHY?”. What changed to make the rudder > position sensor essential? > > Over the years I’ve had an Autohelm tillerpilot (800 I think) on a 27 and a > Raymarine 1000 tillerpilot on my 25 with tiller steering. A Raymarine 3000 > belt driven wheel pilot. And there is a Navico 5000 wheel pilot on my 38 (I’m > sure it isn’t older than dirt, but it is almost older than plastic). None of > these has a wheel sensor – relying only on heading information from the > fluxgate compass built into them to steer the boat. All of them worked well. > > The Navico took a bit of adjustment to the settings to optimize performance > (I suspect the PO had never set it up since the wheel lock to lock setting > was the default and not the proper number for the boat), but once set up the > wheelpilot will steer the boat for miles and miles without a variance from > the desired heading of over a degree or two. > > So what has changed with the newer autopilots to make the rudder position > sensor so important? > > Rick Brass > Imzadi C&C 38 mk 2 > la Belle Aurore C&C 25 mk1 > Washington, NC
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