Raymarine-Ev-100-Wheel-Evolution-Autopilot

[Hayden Watson]

Does the Raymarine-Ev-100-Wheel-Evolution-Autopilot require or if not, will it benefit from a rudder reference input? The P70 control head looks like it shows the rudder angle at the top of the display it does not seem like this would work without some type of reference.
I am sure that it would steer without reference angle but knowing what angle the rudder is at should be enable you to better balance the sails.

 

[jssailem]

Hayden. I have the EV100. It has the availability to add a rudder reference to the system. I know MaineSail recommends it.
I have not had trouble with mine. Balancing the sails is about reefing or putting up smaller sails. When my boat tracks with little or know rudder input I know I have it in balance. Usually take all of 10 minutes on a bad day to get that balance.
Your boat your choice.

 

[Hayden Watson]

My current pilot is a 1988 Autohelm AH4000. (yes it really does still work!) I know that one of these days it is going to bite the dust and will need to be replaced. My biggest complaint with the AH4000 is how noisy the motor is. Is the AV100 system quieter than the older units? Does the motor run at one speed so that the wheel make little jerking adjustments or does the speed vary so that the adjustments are smoother?

 

[Dan_Y]

Raymarine states the EV-1 sensor core (a 9-axis AHRS with body axis accelerometers, angular rate sensors and magnetometors) with the Autopilot Control Unit reduces the need for the rudder position transducer. However, the rudder transducer lets the ACU-100 (in my case) know the rudder angle limits so it can't hit the stops, and allows the rudder deflection angle to be shown on the p70s display (+/- 30deg). I sent a product improvement suggestion to RM asking to allow the user to set the displayed rudder limits on the p70s to +/- 5 or +/-10deg to see the effect of sail trim more easily. Jackdaw posted somewhere I think that you want between 2-4 deg of rudder angle when pointing as a performance sweet spot between rudder lift and drag. Because I use the AP 95% of the time while cruising, I use the rudder angle display to trim the sails at 2-4 deg of rudder when pointing. It's a little difficult to trim sails while holding the helm. On a good day I can disengage the A/P when trimmed and the boat will hold course for a while. But older sails make trimming a constant chore it seems. Also a quick glance at the rudder angle is another way to see if I let the sail trim get away. Sometimes I can hear the large whirlpools/eddys behind the boat as a big clue the rudder is at 7deg or more....haha. The ACU-100 will add rudder until it gives up, probably based on the wheel pilot stepper motor current draw, trying to hold some big rudder angle load.

To Hayden, the ACU's still drive what seems to be a stepper motor in the venerable MK II Wheelpilot and they certainly aren't nearly silent like a linear drive. Only been on a sailboat with a linear drive once, and it was silent...really nice.

 

[HMT2]

Does the Raymarine-Ev-100-Wheel-Evolution-Autopilot require or if not, will it benefit from a rudder reference input?

I have a recently installed Ev100 with no rudder sensor and it tracks very well when sailing a heading, a wind angle, or sailing to a waypoint.

 

[Maine Sail]

Does the Raymarine-Ev-100-Wheel-Evolution-Autopilot require or if not, will it benefit from a rudder reference input? The P70 control head looks like it shows the rudder angle at the top of the display it does not seem like this would work without some type of reference.
I am sure that it would steer without reference angle but knowing what angle the rudder is at should be enable you to better balance the sails.

While it does better than earlier versions the rudder reference sensor still makes a big difference. I won't install one without it.

 

[Hayden Watson]

While it does better than earlier versions the rudder reference sensor still makes a big difference. I won't install one without it.

Maine Sail, do you have an article explaining the why and wherefore of rudder reference. I would like to understand why you think it important. My thinking is that knowing the rudder angle would give me reference as to when my sails are in balance. On the other hand, I have a light line wiped onto my wheel that is on top of the wheel when coasting in a strait line. I positioned it by motoring at hull speed then shifting to neutral and holding a steady course. I used this method because the prop wash causes a lot of helm and the helm when sailing can be affected by sail trim.
Does the rudder reference provide any more info then I get from my marked wheel?

 

[Head Sail]

The EV-100 will work without the rudder reference unit but it will use the GPS to determine your direction and "guess" at the rudder position which could result in over correction to get back on course. On flat water it works best. In a heavy sea state, not so well. I don't have a RRU and it works fine when under power. Under sail it will often be slow to correct and over correct with gusts.
Without the RRU, the sensor does not know your direction has changed until a GPS signal tells it so which could be several seconds after the rudder has changed position. With the RRU it knows immediately your direction is changing.

 

[jeepbluetj]

My understanding is that the RM wheelpilots "guess" at the rudder position without a reference transducer. I.e. if it's turned port for n milliseconds, the rudder is left x degrees. Basically the output of the autopilot computational loop is rudder position - and if it knows that accurately, it'll undercorrect/overcorrect less. Even with a GPS, the gps input is slow, and filtered quite a bit. The accel/gyro/magnetometer is the primary attitude input to an autopilot (the 'fast' part - not really fast on a sailboat)\

 

[Maine Sail]

Does the rudder reference provide any more info then I get from my marked wheel?

Absolutely, but a rudder reference is not really about you... The rudder reference lets the AP's computer know exactly where the rudder is which means more information, less guessing, less wandering, lower energy consumption, and better steering under all conditions.

These wheel drives can easily slip under heavy load yet the course computer has no way to know the belt has slipped, unless it is connected to a rudder reference to tell it exactly where the rudder is.

Raymarine has been trying like hell to get rid of a rudder reference for years, and with the new EV series it is better, but still not perfect. I turned down two AP jobs last year because the owners did not want to install the rudder reference. This was all because Raymarine suggested "it may not be necessary". If I can't do a job correctly I will simply walk away from it and move onto customers who do want things done correctly. Installing an EV wheel pilot, without a rudder reference, I consider to be "not doing the job correctly"..

 

[jssailem]

You guys are correct about the concept of the AP. It functions very similar to a heat seeking missile (which is a total misnomer. I senses cold air not heat. And turns away from the cold).
The sensor is sampling your GPS track and as you very from the course it corrects. When waves and wind conspire at a faster rate than the sensor can detect you slide a bit down the face of swells. The RRU helps the ACU to maintain course when the conditions change and try to push your boat off course.

 

[stephen_i_w]

I have an EV-100 system without a rudder sensor. It works pretty well in light air and flat water. My question is whether a rudder sensor would help in difficult conditions such as waves hitting the boat or sailing in heavy air.

 

[jssailem]

Stephen

My question is whether a rudder sensor would help in difficult conditions such as waves hitting the boat or sailing in heavy air

Certainly it will help. It will provide a signal to the AP CPU that there is a force hitting the rudder and altering the position. This will happen faster than the signal from the signal from the compass/GPS sensor.

Let's look at the other physical forces at play. Will the addition of a rudder sensor help in difficult conditions?
Likely not.
Consider a wave hitting the rudder with enough force to change the position of the rudder. That force is going to be transmitted up through the system to the wheel and it is going to try and rotate the wheel. Standing guard against that action is the plastic Wheel unit, it's gears, the belt and the motor. While at the same time the motor is getting signals from the CPU "We are off course Turn Back Turn Back". You in the cabin trusting the AP is doing it's thing suddenly feel the impact of the wave and the change of boat position as the wave runs under the boat and the boat starts to slip off the wave.

For me the answer is Hell No. The AP is not going to be able to solve the problem for long in difficult conditions or heavy air. The plastic gears, the motor or your sanity/tolerance - something is going to give out before long.

If you are at the helm, you will feel the pressure of the wave or even see the wave and react with far more speed than any AP system.

Now how often you will sail in such conditions may help influence how you deal with the need of a "beefy" AP. Even with a $5000 super AP, the reaction time and the adjustment to the conditions will not match your reaction time at the helm. The more expensive AP will be able to handle heavier conditions and may be of value as you decide your sailing/cruising plan will expose you a lot.

Boat Bucks can influence most cruising problems.