Autopilot Raymarine

[Oceansailor]

I have a Raymarine 400G course computer. It was installed 2003 and is still working. Steering performance is as good as it was when installed.



Still I'm looking for ways to improve steering performance as it essential for my type of ocean sailing.



I would appreciate any comments from users who have upgraded to the new EV-400 Sail.



Is there a significant improvement in performance?



Next question:



Another way of improving steering would be to upgrade to a satellite GPS compass and keep the 400G course computer.



I would be grateful if anyone that might have a working combination of 400G course computer and a satellite GPS compass could share information on how it is working?

[donradcliffe]

Have you upgraded to a rate Gyro yet?

http://www.cruisersforum.com/forums/...5-a-53175.html

[Oceansailor]

Yes there is a rategyro sensor in the course computer and it is performing accordingly.

[donradcliffe]

You'e the first person I've heard complaining about ongoing poor steering performance with a Raymarine rate gyro. There are a myriad of potential causes, and i don't think the satellite GPS is going to cure them.

Maybe you could be more specific about your performance issues, and start by giving us some more info about the boat, rudder system and autopilot hardware, when it was installed, and who did it, and whether you have messed with the default settings. Then we can get the autopilot whisperers on the job.

[Oceansailor]

Originally Posted by donradcliffe

You'e the first person I've heard complaining about ongoing poor steering performance with a Raymarine rate gyro. There are a myriad of potential causes, and i don't think the satellite GPS is going to cure them.

Maybe you could be more specific about your performance issues, and start by giving us some more info about the boat, rudder system and autopilot hardware, when it was installed, and who did it, and whether you have messed with the default settings. Then we can get the autopilot whisperers on the job.

Thanks for your time trying to answer my questions. I must have expressed myself wrong.

I have not been complaining about poor steering perfomance. I have sailed many miles offshore and the autopilot is doing good. Having in mind that it is 14 years old it is actually very good. I have sailed with later designed Simrad and Furuno pilots on Atlantic crossings. Non has performed as good as my Raymarine pilot. I consider the autopilot to be the most important equipment. Good steering perfomance is so important for comfort and the longevity of the steering components.

My question is if 14 years of product development of logarithm and electronics have made pefomance even better? I had hoped that is the case. Most other electronics has developed quite a lot during the same period!

The other question was the perfomance with satellite GPS compass. I'm sure that a satellite compass would improve steering, if the course computer can read and process the better/faster data. Im not 100% sure that is the case?

[Neptune's Gear]

The single best improvement you can do is a solid state compass with rate, pitch roll and yaw compensation. Like the Navico precision 9, or the airmar one. Pretty much immune to boat motion, and heading always accurate to within 2 degrees. It's more improvement in performance than the difference was between a fluxgate and a rate compass. Huge improvement in course keeping . :-)

[Oceansailor]

Originally Posted by Neptune's Gear

The single best improvement you can do is a solid state compass with rate, pitch roll and yaw compensation. Like the Navico precision 9, or the airmar one. Pretty much immune to boat motion, and heading always accurate to within 2 degrees. It's more improvement in performance than the difference was between a fluxgate and a rate compass. Huge improvement in course keeping . :-)

Thanks for the suggestion!

My autopilot is NMEA0183 and the rest Furuno NN3D NMEA2000

The need for both 0183/2000 made me look at the Airmar H2183.

Questions:

I understand from reading on another forum that the existing fluxgate should be disconnected from the course computer in order to force it to read the NMEA port.

Will the autopilot be able to read rate data from the Airmar? Or will it use the rate chip in the course computer?

[Neptune's Gear]

I don't think that your existing computer has any rate capability- but I haven't read that manual, so could be wrong. Yes, disconnect the old compass. Your ap will still benefit ( a lot) from the much more accurate heading data :-) next in line though, would be a ap computer.

[toddedger]

The beauty of the Raymarine Evolution is its ability to evolve. While advances in steering to a compass course have small room for improvement, the biggest gains have been in steering to apparent wind. There have been several software upgrades since the EVO came out, the latest allows it to use windspeed in the algorithm. Your current pilot might do well on a compass course, but can it steer your boat to windward under sail?

While rate gyros improve compass course performance, they can only react to going off course. When the EVO senses wind and heel increases it can react before the vessel goes off course.

For me the big advance with the Evolution AP has been the performance under sail in gusty reaching conditions where weather helm loads are constantly changing, and the ability to now steer my boat to windward. The new technology steers with near human like response, without human like fatigue.

I think an upgrade to an Evolution pilot on a NMEA 2000 network would be a far better improvement than a more accurate GPS compass.

[donradcliffe]

If you want direct comparisons, look at the dark side;

Satellite Compass Questions - Trawler Forum

I'd say the jury is still out.

[Oceansailor]

Yes I was looking at the spec. for the Raymarine EV-400Sail. You get a better compass and updated software. It is tempting:-) just read that there is a major update out for the EV pilot.

I do use the windsteer mode much more than compass steering mode when sailing offshore. As I said before the autopilot is doing quite good. I do believe that even in wind mode, compass and rate information is crucial.

Did you have another autopilot before the EV-400 or is the first autopilot on that boat?

I have a PG-700 Furuno compass connected to the NMEA 2000 bus. This should be a better compass than the Ray fluxgate. Unfortunatly the autopilot have no NMEA2000. But perhaps an interface converting 2000 to 10 Hz 0183 would solve that problem?

[Frankly]

If you think about holding a constant heading under varying forces on the yacht it is important to realize that the rudder does not control the heading of the vessel but the heading rate of change. It is the integration of the heading rate (technically yaw rate) by either the helmsman or some automatic system that yields the desired constant heading. In an ideal world if I drive the vessel to a desired heading and then maintain the heading rate at zero then the yacht will continue on that heading forever.

My point is the addition of a yaw rate sensor is one of the biggest improvements one can make in a "better autopilot". We are now measuring what we really want to control not some related parameter. While a GPS real heading system (not course) could provide that measurement, we now have less that $10 chips that can do a more than adequate job.

I did some tests with the early S series Raymarine AP controllers. If you turn the control unit (with the rate sensor inside) and leave the fluxgate fixed it is around 2 minutes for the heading error to return to zero. Meaning the AP control is almost completely ignoring the fluxgate unit and relying on the rate sensor for heading input. Because all sensors have a bias error if you integrate the rate sensor for a long time an error will creep into the measurement. This is where the fluxgate heading is used.

Get an AP with a yaw rate sensor and you will make a significant improvement in heading control. If you don't have a rudder feedback sensor, add one and also dramatically improve AP performance.

[Oceansailor]

Originally Posted by Frankly

If you think about holding a constant heading under varying forces on the yacht it is important to realize that the rudder does not control the heading of the vessel but the heading rate of change. It is the integration of the heading rate (technically yaw rate) by either the helmsman or some automatic system that yields the desired constant heading. In an ideal world if I drive the vessel to a desired heading and then maintain the heading rate at zero then the yacht will continue on that heading forever.

My point is the addition of a yaw rate sensor is one of the biggest improvements one can make in a "better autopilot". We are now measuring what we really want to control not some related parameter. While a GPS real heading system (not course) could provide that measurement, we now have less that $10 chips that can do a more than adequate job.

I did some tests with the early S series Raymarine AP controllers. If you turn the control unit (with the rate sensor inside) and leave the fluxgate fixed it is around 2 minutes for the heading error to return to zero. Meaning the AP control is almost completely ignoring the fluxgate unit and relying on the rate sensor for heading input. Because all sensors have a bias error if you integrate the rate sensor for a long time an error will creep into the measurement. This is where the fluxgate heading is used.

Get an AP with a yaw rate sensor and you will make a significant improvement in heading control. If you don't have a rudder feedback sensor, add one and also dramatically improve AP performance.

Rate sensor and rudder feedback unit is already part of the installation. I take for granted that the factory installed rate sensor is the same as "yaw rate sensor"?

[Frankly]

Not familiar with the 4000 series APs, but kind of figured the "G" on the end of the model number was an indication of a gyro (ie rate sensor). If your system is working as initially designed then you are probably 90% of what is currently available. I am currently operating with the X series of Raymarine and the improvements over the "S" series are subtle but noticeable. I don't use the learning modes, but each generation of AP systems should improve in setting optimum parameters for the installed vessel.

Keep in mind that the rudder position sensor is a wear item. Just hanging on the hook any slight rudder movement is wearing that potentiometer.

The Evo system now includes a non gimballed heading sensor and I assume the yaw rate signal is also compensated for vessel heel with the accelerometer info (if you are lying on your side the yaw rate sensor is now indicating pitch rate).

Your money your call, but don't believe trying to include a GPS based heading sensor would be dollars well spent.

[Oceansailor]

Thanks for the information about your thoughts on improvements with the X series. Very helpful. I tend to agree with you that a GPS compass might be an overkill for an old autopilot.