Which Auotpilot Best For This Boat?

[Captain Bill]

I recently(July) purchased a Raymarine EV1 Hydraulic autopilot to replace my aged ST5000+. I cannot recomend anyone put one of these EV1 autopilots on a sailboat at this time. There is some sort of issue with the software that commands a 30 degree turn to reacquire a track if off track by as little as .01nm (60FT). This has occurred on my boat to crossing in front of an inlet on an outgoing tide while sailing down wind. Had the preventer not been in place it would have been a crash gybe. If one has to dodge an object in the water it will do the same to reacqire the course. I have placed an inquiry to Raymarine as to whether this is a bug or by design, but have not received a response yet. If by design I would suggest that these autopilots are unsuitable for sailboats as they could cause either crash gybes or put the boat in Irons. My system was calibrated according to instructions. The local Raymarine dealer says he has seen the problem personally when commisioning new autopilots and has reported the problem to Raymarine. He knows of no way to fix the issue. This problem is being discussed on other forums and does not appear to be limited to the hydraulic version. My old st5000+ would make a 30 degree turn to reacquire the track if off track by.1NM(600ft) but made shallow corrections inside of that distance. I'm so paranoid about the unit I take it off of autopilot whenever another boat is overtaking us. We used to refer to the old autopilot as Otto, this new one we call "Crazy Ivan", being somewhat of a Tom Clancy fan.

[colemj]

Bill, does it do this in compass mode or only when following nav data? If the latter, it may be due to the nav data source of XTE and not the AP.

30 degrees is pretty dramatic. Our Simrad AP default is to not make any turn >10* at any time without an acknowledgement from the helm. This default can be intentionally changed in the setup menu. Does yours have a similar user setting that can be set lower?

Mark

[Abgreenbank]

Why would you be in track mode when less than 30 deg apparent wind angle from a gybe. I find when sailing I use wind vane mode and adjust the apparent wind angle to try and follow track.

However I do agree with you that even with small XTE in the track mode it returns to track very aggressively. But the EV autopilots are light years ahead of the previous Raymarine autopilot.

If anything I find that the Ev series needs more options, such as a quick method of selecting a direct intercept to a waypoint when off track or you choose to go to a different non active waypoint.

Maybe raymarine have used Boeing autopilot software as they do exactly the same thing.

Regards

Ab


Sent from my iPad using Cruisers Sailing Forum

[powsmias]

Originally Posted by onestepcsy37

powsmias - i received your private mail, thought i would answer here. No, I don't have a wind vane. For my kind of sailing I don't see any particular good use for one. The longest i've been at sea is four days and the CPT steered the whole way every time. I can understand wind vane steering for long ocean voyages but I don't think I will be making one at my age. OTOH, some folks like to fool around with them so go right ahead if you like. The good ones are as expensive as electric autopilots but have the advantage of being completely self contained when in operation.

When you do install your CPT, use the manual. If you don't have one, they are available at the CPT website in PDF format. Be sure to read the manual cover to cover before doing anything.

They are actually very simple devices with few controls which is one of the reasons I like mine so much. Once you actually get to sea and start using it you will need to play with the two controls until you get to learn how your particular boat reacts to different settings. I eventually found a setting for each control that I used maybe 95% of the time for most sea states.

One control determines how far off course you will allow the boat to wander before applying a rudder correction. The other control determines how much of a rudder correction you will apply to get back on course. My boat is a heavy full keel cutter that balances very well. I found that it was ok to let the boat wander five degrees and make small rudder corrections. Your boat may be different.

And no, you can't connect it to your GPS, for which I can only say, "Thank You Jeff!".

Appreciate the response and thinking before i do anything rash since i have the italian disease "funzalo" i gotta wait for the right used one to come along and be happy i have the cpt.. appreciate all the help mister.. all the best. thanx

[Captain Bill]

Originally Posted by colemj

Bill, does it do this in compass mode or only when following nav data? If the latter, it may be due to the nav data source of XTE and not the AP.

30 degrees is pretty dramatic. Our Simrad AP default is to not make any turn >10* at any time without an acknowledgement from the helm. This default can be intentionally changed in the setup menu. Does yours have a similar user setting that can be set lower?

Mark

The problem is limited to the track mode when trying reacquire a track. I currently work around the problem by manually steering back to the track line and pushing the track button as the cross track error swithes from - to + or vis versa. The EV1 has very limited adjustments and there is no adjustment available or at least none documented or easily found in the menus. On a couple of occasions the system overshot the track by .01 nm and commanded a 60 degree turn (30 degrees to the track line but 60 degrees to the first turn). We were in Maine when that happened and had a pretty good cross tide running that helped with the initial overshoot, but it was still a wild ride. I did not interrupt because there was no one else around and I wanted to see what it would do. The system is reporting a .01 nm cross track error when this occurs. AFAIK the autopilot commands the turns, not the chartplotter, but I may be wrong about that. I have a Raymarine C97 chartplotter with a built in GPS. I also have a Raymarine GPS120. Which was not connected at the beginning. In case it was the GPS I disabled the internal C97 gps and plugged in the GPS120. It made no difference in the behavior at all. My documentaion indicates that cross track error sentences come from the GPS. If that is correct then I would not expect both units to be misreporting the XTE. The GPS120 was used with my ST5000+and I never experienced anything like this with that unit. This is not an intermittent problem, it happens every time. Oddly if one is following a route it does not do this when turning onto a new heading. but does exhibit the behavior if the XTE exceeds .01nm. after acquiring the new course track.

If i was to hazard a guess I'ld guess a programmer slipped a decimal point. Based on the way my old autopilot behaved an initial 3 degree correction at .01 nm would have been about right. If the XTE did not start correcting i believe the next step was a 6 degree turn. If a programmer put in turn 30 degrees instead of 3.0 degrees when the XTE exceeds +.01 NM then subrtact 30 degrees from the track heading and turn, or Add 30 degrees if the XTE exceeds -.01. Of course it could also be a slipped decimal point in the .1 NM XTE statement and it actually was programed as .01 instead of 0.1. Since their older autopilots did a 30 degree turn at .1nm maybe this is even a more likely error. Then again maybe none of these guys are sailors and don't know 30 degree turn might be a bad thing.

In any case, Ill report on Raymarine's response to my inquiry.

[onestepcsy37]

Captain Bill, I know that you are a much more experienced sailor than me, but I gotta tell you there is no way I would let an autopilot take me through an inlet, traffic or no traffic.

There was a large motor yacht, maybe 70ft, that came through Ponce Inlet here a few years ago in a storm. He was advised by a marina dockmaster and Coast Guard Ponce Inlet not to enter. "No problem, I have my GPS hooked up to my autopilot" he said.

The next day a crane was brought in to load the wreckage into dump trucks.

[Captain Bill]

Originally Posted by onestepcsy37

Captain Bill, I know that you are a much more experienced sailor than me, but I gotta tell you there is no way I would let an autopilot take me through an inlet, traffic or no traffic.

There was a large motor yacht, maybe 70ft, that came through Ponce Inlet here a few years ago in a storm. He was advised by a marina dockmaster and Coast Guard Ponce Inlet not to enter. "No problem, I have my GPS hooked up to my autopilot" he said.

The next day a crane was brought in to load the wreckage into dump trucks.

I wasn't going through an inlet, I was going past an inlet. The inlet was about a mile off to my starboard, but there was quite a curent coming out of it. It doesn't take that much to move a boat 60 feet when hit by a current on the beam.

[onestepcsy37]

Was it Fort Pierce? Wicked current there.

[RaymondR]

Raymarine ap's now detect motion in up, down, in, out, backwards, forwards, clockwise, anticlockwise and shakey

Ah, so it's a 3 axis gyro with some accelarometers or just a bunch of accelarometers or a fluxgate, rate gyro and some accelarometers?.

[Captain Bill]

Originally Posted by onestepcsy37

Was it Fort Pierce? Wicked current there.

No, it was in Maine and though being a Florida boy I called it an inlet it was an opening to one of those long narrow bays between Booth Bay Harbor and Casco Bay. It was outgoing tide and up there they are serious about tides. Currents are way worse than Ft. Pierce, which I am quite familiar with. If I remember correctly the tide difference was about 13 feet that day. That moves a lot of water in and out of those openings.

[Captain Bill]

Originally Posted by RaymondR

[URL="http://www.cruisersforum.com/forums/tags/raymarine.html"]

Ah, so it's a 3 axis gyro with some accelarometers or just a bunch of accelarometers or a fluxgate, rate gyro and some accelarometers?.

They have a three axis rate gyro, 3 axis accelerometer, and 3 axis magnetometer. You can buy the chip for less that $10 on line in quantities of 1. They are in virtually every smart phone and most tablets. Put a fancy piece of plastic around it, slap a marine label on it and sell it for $400. Just look up 9 axis sensor on Google.