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Greetings, just bought a 2008 Hanse 470 with a mix of unique tech/networking.

The previous owner had 2 Nav system (1) an Unbuto based Open CPN system running on an old Intel I3 box with a VGA monitor display (2) a Triton B&G chartplotter on a NMEA 2000 backbone.
Hopefully the image i hoped to attach is visible,

If you can see the image, you will note that (1) there is a Rasberry hub in the Middle with connection to
  • an older Garmin 1083 Auto-Pilot,
  • a USB based older GPS Puck,
  • AIS feed,
  • NMEA 1083 <-> 2k converter,
*a wifi routner.

M goal is to get as close to a functioning NMEA 2000 backbone, Get rid of the 7 year old slow Unbutuu box out of the way, and use the existing AutoPilot and AIS GPS for another season.

Question 1: can anyone explain what the Rasberry does? Is it multiplexing,
Question 2: will this work better - run everything off of the B&G chart pllotter and forget about the Unbuto box.
(a) connect the AutoPilot to the NMEA 2K backbone with a dedicated NMEA 2k <-> 1083 converter box
(b) connect the AIS to the network with a dedicated NMEA 2k <-> 1083 converter box
(c) buy a high accuracy GPS antennae and connect it directly to the NMEA 20 Network.

Question 3: Why is everything connected to a wifi router - specifically the radar?

Question 4: why is the radar connected to the wifi router and can it connect directly to the NMEA 2k backbone?
 

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Greetings, just bought a 2008 Hanse 470 with a mix of unique tech/networking.

The previous owner had 2 Nav system (1) an Unbuto based Open CPN system running on an old Intel I3 box with a VGA monitor display (2) a Triton B&G chartplotter on a NMEA 2000 backbone.
Hopefully the image i hoped to attach is visible,

If you can see the image, you will note that (1) there is a Rasberry hub in the Middle with connection to
  • an older Garmin 1083 Auto-Pilot,
  • a USB based older GPS Puck,
  • AIS feed,
  • NMEA 1083 <-> 2k converter,
*a wifi routner.

M goal is to get as close to a functioning NMEA 2000 backbone, Get rid of the 7 year old slow Unbutuu box out of the way, and use the existing AutoPilot and AIS GPS for another season.

Question 1: can anyone explain what the Rasberry does? Is it multiplexing,
Question 2: will this work better - run everything off of the B&G chart pllotter and forget about the Unbuto box.
(a) connect the AutoPilot to the NMEA 2K backbone with a dedicated NMEA 2k <-> 1083 converter box
(b) connect the AIS to the network with a dedicated NMEA 2k <-> 1083 converter box
(c) buy a high accuracy GPS antennae and connect it directly to the NMEA 20 Network.

Question 3: Why is everything connected to a wifi router - specifically the radar?

Question 4: why is the radar connected to the wifi router and can it connect directly to the NMEA 2k backbone?
1- It seems clear the Raspberry pi is used to get all the information on ethernet from 183 and 2k to connect to OpenCPN. It can also allow routing gps, depth..ect to the Zeus. It provides AIS to openCPN and possibly Zeus.. You seem to have an issue that not everything is able to talk 2k.. so the PI converts these 183 devices to ethernet.. it also connects your 2k devices to ethernet.

2- Depends if Zeus is able to do something with all the data. OpenCPN can digest a multitude of sources. Your 183 devices dont seem to be able to talk 2k.. so the only solution is convert 183 to 2k.. which your existing solution can provide through the PI. Or the 183 can connect to ethernet through the PI.

3,4- Radar must connect ethernet.. 2K is way too slow to send high precision radar across. It could be that the PO realized the radar must connect to Zeus through ethernet, so just added the router and connected everything else up also.

I somewhat agree the existing system seems a bit dependent upon a variety of different pieces.. it is not clear all of your pieces would work properly with 183/2k converters.. the fundamental issue is that 183 is not able to digest all the information coming from 2k.. so the 183 converters will be overloaded without some type of sentence filtering.. the PI is capable of filtering certain sentences.. depending how it was programmed.

As a side issue.. the future is ethernet.. not 2k
 

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Discussion Starter · #3 ·
1- It seems clear the Raspberry pi is used to get all the information on ethernet from 183 and 2k to connect to OpenCPN. It can also allow routing gps, depth..ect to the Zeus. It provides AIS to openCPN and possibly Zeus.. You seem to have an issue that not everything is able to talk 2k.. so the PI converts these 183 devices to ethernet.. it also connects your 2k devices to ethernet.

2- Depends if Zeus is able to do something with all the data. OpenCPN can digest a multitude of sources. Your 183 devices dont seem to be able to talk 2k.. so the only solution is convert 183 to 2k.. which your existing solution can provide through the PI. Or the 183 can connect to ethernet through the PI.

3,4- Radar must connect ethernet.. 2K is way too slow to send high precision radar across. It could be that the PO realized the radar must connect to Zeus through ethernet, so just added the router and connected everything else up also.

I somewhat agree the existing system seems a bit dependent upon a variety of different pieces.. it is not clear all of your pieces would work properly with 183/2k converters.. the PI is also capable of filtering certain sentences.. depending how it was programmed.

As a side issue.. the future is ethernet.. not 2k
"Thanks, would you recommend connecting everything through Ethernet and the the PI.'. CPN seems great but I am trying to decipher a bunch of ETL code all day . Is there some way to use these open source tools without having to learn all the libraries for each device and processor?". I tried to buy Simrad end point devices but they all seem to be protocol constrained, in this case nm2k. Can I just wire the boat with Ethernet"
 

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"Thanks, would you recommend connecting everything through Ethernet and the the PI.'. CPN seems great but I am trying to decipher a bunch of ETL code all day . Is there some way to use these open source tools without having to learn all the libraries for each device and processor?". I tried to buy Simrad end point devices but they all seem to be protocol constrained, in this case nm2k. Can I just wire the boat with Ethernet"
Thats an interesting problem.. i was trying to think what i would do in your shoes.. Unfortunately, ethernet is not really much of an option with your current electronics other than the way it is done through the PI or an intelligent converter..

When i said ethernet, i was referring to all its forms such as wireless in addition to wired. Once the information is in the router.. it can be wirelessly sent to any computer. Devices such as Zeus can talk wired to the router. If you want OpenCPN.. but don't like Ubuntu, you can use any newer Windows PC.

To allow bi-directional 183, some type of sentence filtering will probably be required.. and thats done in the PI.. So is your ETL implementation using some sort of ETL libraries with Python or C? Seems like over kill.. but i have not researched any open source conversion programs because i would just write it myself in c.

So sorry i can't offer any advice there..
 

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If you really wanted to simplify that and get rid of the OCPN/Ubuntu/Pi/router, then buy a Raymarine Seatalk to N2K converter and STNG-N2K cable for $100 and connect the AP to the N2K network ( https://www.amazon.com/Raymarine-Seatalk1-Sea-Talk-Ng-Converter/dp/B003E1WVRW ), connect the radio output to the NK-80, connect the radar ethernet to the back of the Zeus, use the Zeus's internal GPS, and toss the rest.

Mark
 

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Sailing with instruments
The way I see it a MFD/GPS plotter is the key interface. They come with built in GPS... and you can connect, radome, speed log, depth sounder, wind speed/direction masthead transducer, water temp, AIS. You can link to a VHF for DSC calling. You can drive some APs from some MFPs. You can add 4x4 dash displays for numeric date..BS, TWS, AWA, AWS and so on. Dash displays are easy to read from anywhere in the cockpit (usually)

You should have a MFD plotter where you steer the boat from (binnacle mounted in most cases) or readable from wherever you are steering from. You can add a 2nd MFD below decks to display charts, AIS, position, and all numeric data.

Apparently sailors are now using standard laptops these days for navigation... The wisdom of this eludes me... not suited for the marine environment... difficult to mount/secure. Tablets may be a bit better and a smart phone even better... but the displays are small.

Personally I want 4x4 dash displays for speed, depth and wind data.... and a plotter to see where I am on a chart... which can have AIS and even weather overlays as well as RADAR. I find Navionics on a smart phone does the job. I don't bother with routes and enter a single way point as needed for heading info. The course and heading lines and tracks on a plotter are the most useful features.

I only have two hands and two eyes to do all sailing functions,
 

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If you really wanted to simplify that and get rid of the OCPN/Ubuntu/Pi/router, then buy a Raymarine Seatalk to N2K converter and STNG-N2K cable for $100 and connect the AP to the N2K network ( https://www.amazon.com/Raymarine-Seatalk1-Sea-Talk-Ng-Converter/dp/B003E1WVRW ), connect the radio output to the NK-80, connect the radar ethernet to the back of the Zeus, use the Zeus's internal GPS, and toss the rest.

Mark

It just occurred to me that you could connect the VHF/AIS directly to the NMEA0183 input of the Zeus and do away with the NK-80.

Mark
 

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I know sailors that like to connect all sensors to a computer to log sensor values and display on the ship computer (Ubuntu in your case).

I use OpenCPN exclusively for route planning offline.. I use a Garmin plotter for online navigation, AIS and radar overlay.. My computer has its own GPS device, so it needs no sensor data.

i would tend to agree with others if you do not want a computer connected to your sensors..

To create this sort of solution.. I would connect the radar directly to the Zeus for radar.. 183 from the VHF to Zeus for AIS..

The autopilot does not need wind unless you usually pilot to wind... in this case the autopilot directly connects its fluxgate..

I am not a fan of connecting single sided CAN to differential can, so i would be careful about connecting these three different 2k manufacturers together.. this would mean the 2k connects only to the Zeus. And Raymarine connects directly to its fluxgate.

This is probably the simplest solution that gets rid of ethernet, ubuntu, PI and all converters, without buying anything.
 

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The autopilot does not need wind unless you usually pilot to wind... in this case the autopilot directly connects its fluxgate..

I am not a fan of connecting single sided CAN to differential can, so i would be careful about connecting these three different 2k manufacturers together.. this would mean the 2k connects only to the Zeus. And Raymarine connects directly to its fluxgate.

This is probably the simplest solution that gets rid of ethernet, ubuntu, PI and all converters, without buying anything.
Not sure I understand your point about single sided CAN to differential CAN. I'm not even sure that is even valid electrically, since every single component listed is differential - even the converters. There isn't any such thing as "different N2K manufacturers" because N2K is just a standard that all manufacturers have to meet. There aren't different "flavors" of N2K, and even Raymarine's perversion of it is simply in the physical connectors only. Even the Seatalk converter to N2K meets the standard and works fine.

So put everything on the N2K bus and all will happily share data and work together.

Not having wind or navigation data available to the autopilot is severely limiting its functionality and usefulness. It can easily achieve all of its potential by connecting it to the main N2K network via the ST-N2K converter. Of course, the compass, rudder reference, and control head will all be directly connected to the AP computer, but the AP computer will be bridged to the N2K, so all wind, GPS and navigational data will be available to it, and its compass and rudder data will be available to the other components.

The above is from direct experience. We have a ST6001 AP system connected to a N2K bus that also has a dog's breakfast of different manufacturer equipment, including two 0183-2000 converters, and a Standard Horizon VHF/AIS. No problems at all with this.

Mark
 

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Concerning autopilots.

I believe most newer autopilots will interface with a GPS plotter and steer to a waypoint. But can those APs simply be set to steer a magnetic course?

One of the hassles of driving the boat manually at the helm is boredom and the other is fatigue. AP solves that problem perfectly. A helmsman usually steers a magnetic course... to "a fixed point" such as a buoy or land feature... or a magnetic course (using the binnacle compass)... or to the wind to keep the tell tails flowing. When steering a magnetic course or aiming to a fixed point one often has to trim the sails as the wind direction and or strength changes. Of course motoring essentially "ignores" the wind most of the time. However it may make sense to consider the wave action. There are APs which can sail to a wind angle... but that may not get you to the mark you want. Long story short... sailing with an AP is / can be a dynamic process. Motoring to a point is hardly dynamic. GPS driven AP will "consider"... set and drift'' leeway and current... always pointing the boat and steering to a GPS set point. As it does, crew will trim the sails accordingly. Sailing with an AP requires the crew to trim (usually) to maximize boat speed/velocity to destination.

Are sailors using AP these days mostly sailing to a fixed GPS determined location? Or are they sailing a magnetic course? Or are they sailing to a set wind angle?

My AP does not accept GPS waypoints or sail to a wind angle.... it sails to a "set course". It's like having a helmsman that you tell... sail 230 magnetic... and they do it. Someone (me) trims the sails. You tack or jibe by setting the new course, and dealing with the sail trim. I find the AP tremendously helpful. I often set a waypoint which I can see on the chart plotter and data about the waypoint on dash displays...DTW, TTG, CTW, VTD and so on. I will do a combination or tweaking the course heading and trimming the sails. What I don't have to do it be stuck at the helm.. YEAH! I digest the data from the instruments and select the course to steer... observe (watch keeping) and do various things... like make a cup of coffee.

Are you using your AP to steer to a fixed coordinate (waypoint) or to a magnetic course (to a waypoint or mark/feature of the land etc.? Do you rely on tell tales, a windex or wind data on instruments when sailing with the AP?
 

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Concerning autopilots.

I believe most newer autopilots will interface with a GPS plotter and steer to a waypoint. But can those APs simply be set to steer a magnetic course?
Yes, that is the most basic level functionality that all of them share. All autopilots are standalone, and interfacing them just provides extra functionality.

Are sailors using AP these days mostly sailing to a fixed GPS determined location? Or are they sailing a magnetic course? Or are they sailing to a set wind angle?
.....
Are you using your AP to steer to a fixed coordinate (waypoint) or to a magnetic course (to a waypoint or mark/feature of the land etc.? Do you rely on tell tales, a windex or wind data on instruments when sailing with the AP?
All of the above.

AP to compass: used mostly when we just want to push a button to keep a straight course while we fiddle with something. Often used while entering/leaving an anchorage and getting things out/away before setting on a determined course.

AP to waypoint or course (pretty much the same thing): used a lot while actually sailing. Like you mention, one needs to trim sails accordingly while in use.

AP to wind: mostly used when beating or running because sails don't need to be trimmed and it prevents unintentional jibing or going in irons on wind shifts. Also often used when raising sails to keep the boat headed into the wind in an anchorage where the wind is usually shifty.

We rely on telltales to help with sail trim. Have a windex and wind instrument that are used to make navigation decisions - our favorite instrument setup is to have one instrument displaying the traditional wind rose with AWD and TWD along with instantaneous wind speeds, and another displaying a timeplot histogram of TWD and TWS. The latter gives us a good feel for changing wind conditions and whether they are temporary or truly changing.

Mark
 

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Yes, that is the most basic level functionality that all of them share. All autopilots are standalone, and interfacing them just provides extra functionality.



All of the above.

AP to compass: used mostly when we just want to push a button to keep a straight course while we fiddle with something. Often used while entering/leaving an anchorage and getting things out/away before setting on a determined course.

AP to waypoint or course (pretty much the same thing): used a lot while actually sailing. Like you mention, one needs to trim sails accordingly while in use.

AP to wind: mostly used when beating or running because sails don't need to be trimmed and it prevents unintentional jibing or going in irons on wind shifts. Also often used when raising sails to keep the boat headed into the wind in an anchorage where the wind is usually shifty.

We rely on telltales to help with sail trim. Have a windex and wind instrument that are used to make navigation decisions - our favorite instrument setup is to have one instrument displaying the traditional wind rose with AWD and TWD along with instantaneous wind speeds, and another displaying a timeplot histogram of TWD and TWS. The latter gives us a good feel for changing wind conditions and whether they are temporary or truly changing.

Mark
Your instruments are more sophisticated (newer) than mine. All of mine are from the 80s. I added an MFD with radar and an AP in the late 80s. Last purchase was a Zeus T7 which has on board GP and I use in a coach roof winch. And newer is Navionics on my smart phone.
My dash displays Depth, Boat Speed, Analog Apparent Wind direction (relative to boat) Apparent Wind Speed... then I have a display I can select to display: True wind speed, true wind angle, COG, SOG, DTW, CTW, TTG. I usually toggle between SOG and COG. I check the dash displays data frequently. I steer a course with the AP which does not interface to GPS. I usually steer heading the boat to a point on the plotter... plotter shows a heading line to infinity. When I steer with the heading line I don't bother with the actual numeric heading. I can also see if that heading takes me over thin water etc. The entered waypoint will simply give me an idea of when I will arrive... not that I can do anything about it. I find using the plotter's heading line is all I need for "on the fly" navigation... I don't do route planning.

++++

If got a new API would likely not use the navigate to waypoint much... continuing to use the plotter and steer with the heading line. I recall trying to help newbies steer the boat... Often I would tell them to steer aiming the boat to the red house... they always had problems steering to the binnacle compass. Steering with a heading line is the analog to steering to the red house.
 

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Not sure I understand your point about single sided CAN to differential CAN. I'm not even sure that is even valid electrically, since every single component listed is differential - even the converters. There isn't any such thing as "different N2K manufacturers" because N2K is just a standard that all manufacturers have to meet. There aren't different "flavors" of N2K, and even Raymarine's perversion of it is simply in the physical connectors only. Even the Seatalk converter to N2K meets the standard and works fine.

So put everything on the N2K bus and all will happily share data and work together.

Not having wind or navigation data available to the autopilot is severely limiting its functionality and usefulness. It can easily achieve all of its potential by connecting it to the main N2K network via the ST-N2K converter. Of course, the compass, rudder reference, and control head will all be directly connected to the AP computer, but the AP computer will be bridged to the N2K, so all wind, GPS and navigational data will be available to it, and its compass and rudder data will be available to the other components.

The above is from direct experience. We have a ST6001 AP system connected to a N2K bus that also has a dog's breakfast of different manufacturer equipment, including two 0183-2000 converters, and a Standard Horizon VHF/AIS. No problems at all with this.

Mark
The network shown has two different versions of CAN.. Raymarine setalk and 2k.. the PO specifically did not connect these two networks together.. rather, he connected them together through the RP.. so no he did not connect the 6001 to 2k

And yes, there is single sided and differential can.. there is also galvonic isolated and non-isolated can.. as far as i know nema 2k is only the protocol and the hardware is CAN.. usually DeviceNet..

Most CAN circuits separate the electrical driver from the CAN controller chip because the semiconductor circuitry is different technologies.. so the designer make make his own driver.. when i put CAN on one of my designed boards, it is always galvanically isolated and differential.. automobiles and most n2k are not isolated, so drivers can often be blown due to issues with ground currents and transient bursts..

I have seen drivers get blown on marine N2k networks (on my boat also) because they are not quite as compatible as we would like them to be..
 

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Concerning autopilots.

I believe most newer autopilots will interface with a GPS plotter and steer to a waypoint. But can those APs simply be set to steer a magnetic course?

Are you using your AP to steer to a fixed coordinate (waypoint) or to a magnetic course (to a waypoint or mark/feature of the land etc.? Do you rely on tell tales, a windex or wind data on instruments when sailing with the AP?
these are excellent questions..

I run almost exclusively to compass course.. quite simply because i may be tacking.. kind of hard to tack if your GPS is calling the shots.. also.. i am often dodging things.. crab pots, other boats.. buoys.. again.. GPS cannot provide me this functionality..

I mostly run to flux while in the rivers and ICW because course corrections need to be made due to different buoy locations.. same with coming into or exiting inlets..

I sometimes will run to wind.. but rarely..

Running a 200 or 300 mile run, winds will often change causing me to change course to get a more favorable speed. As a result of these issues.. i rarely run the auto pilot with the GPS.. on the other had, i am always following a course on the GPS.. even if i am tacking back and forth across it..

Since Raymarine comes with a flux compass.. more than likely this owners boat did not need a connection to the 2k compass.. So he could probably disconnect and run to compass.

Probably the best investment I made was replacing the old Raymarine 4000 iirc.. with a new Raymarine Evo.. the 9 axis accelerometer sensor has the autopilot turning the rudder as the boat slews through waves even prior to being off course.. it reacts like a human pilot..
 

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these are excellent questions..

I run almost exclusively to compass course.. quite simply because i may be tacking.. kind of hard to tack if your GPS is calling the shots.. also.. i am often dodging things.. crab pots, other boats.. buoys.. again.. GPS cannot provide me this functionality..

I mostly run to flux while in the rivers and ICW because course corrections need to be made due to different buoy locations.. same with coming into or exiting inlets..

I sometimes will run to wind.. but rarely..

Running a 200 or 300 mile run, winds will often change causing me to change course to get a more favorable speed. As a result of these issues.. i rarely run the auto pilot with the GPS.. on the other had, i am always following a course on the GPS.. even if i am tacking back and forth across it..

Since Raymarine comes with a flux compass.. more than likely this owners boat did not need a connection to the 2k compass.. So he could probably disconnect and run to compass.

Probably the best investment I made was replacing the old Raymarine 4000 iirc.. with a new Raymarine Evo.. the 9 axis accelerometer sensor has the autopilot turning the rudder as the boat slews through waves even prior to being off course.. it reacts like a human pilot..
My AP only steers to a compass direction and has it's own fluxgate compass. You see the course with a large round dial with degree markings... it's like a tiny helm. The APs electronics can limit yawing and the responsiveness... making small corrections. It's very intuitive to use. And pretty much like having someone at the helm. My AP controls are ergonomically and conveniently located where I can see and access my cockpit plotter, dash instruments, engine controls as well as the main and head sail sheet winches. I can AP steer from a protect location with excellent visibility. To tack I make a large course change of 100-120 degrees and adjust as I see the wind and seas and to jibe I slowly turn to dead down wind.... jib the main and head sail and slowly turn to the new down wind course. Its algorithm adjust to sea state supposedly.
So as I said...and I repeat... I set the compass course based on what I see...with the heading line on the plotter. Rather than set a coordinate for a waypoint.. I turn the AP dial so that the heading line on my plotter(s) intersect the location I want to get to. This often means trimming as one does when manually holding a course.
I see no advantage to the capability to steer to a coordinate. I am still very much involved in all sailing decisions... steering, trim, and watch keeping.
 

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the PO specifically did not connect these two networks together.. rather, he connected them together through the RP.. so no he did not connect the 6001 to 2k
He did this for two reasons that I can see. First, he wanted the radar and all the data on OCPN, which doesn't use N2K for communication - 0183 and TCP only. Second, the Seatalk on his AP is 0183, not N2K, so the Pi is being used as a 0183 multiplexer. The later version of SeatalkNG is N2K with a non-microC connector. The only reason for this is because SeatalkNG carries an extra wire that makes it compatible with the older Seatalk. Otherwise, it is standard N2K. I just made a SeatalkNG-MicroC cable by cutting one end, clipping off the extra wire, and adding a MicroC connector.

If the OP wanted the Pi and Ubuntu units removed, then my suggestion above will work with no issues. There is no problem putting Seatalk onto a N2K network. They aren't two different versions of CAN - the Seatalk 0183 will be converted to N2K by the Seatalk-2000 converter. Both the Seatalk converter and the NK-80 are galvanically isolated and differential.

We have these exact conversion systems running on our boat for years without issue.

Mark
 

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Probably the best investment I made was replacing the old Raymarine 4000 iirc.. with a new Raymarine Evo.. the 9 axis accelerometer sensor has the autopilot turning the rudder as the boat slews through waves even prior to being off course.. it reacts like a human pilot..
Thanks for reinforcing this point. I've pointed out many times that today's AP's are completely different beasts compared to those just a few years ago, and can steer a boat through all conditions better than a human. It seems I'm rarely believed. Most of this increased performance is due to the significant advances in compasses, higher data rate GPS and wind transducers, as well as steering algorithms designed to use all of these data.

When we changed in 2010 from what was the top AP 10yrs earlier to a good consumer AP, I was shocked at how much better it was. When we changed boats 3yrs ago and put on a current AP and a 10hz wind, 30hz GPS, 20hz compass that also outputs heave data, and steering algorithms that incorporate all of this, the difference was noticeable again.

We never worry about broaching or overcoming the AP's ability to steer. If there are conditions where these could happen, we haven't encountered them yet.

Mark
 

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I see no advantage to the capability to steer to a coordinate. I am still very much involved in all sailing decisions... steering, trim, and watch keeping.
For example, motoring - particularly in a cross current. Yes, one can sit at the AP continually adjusting the course to meet a waypoint, but it is much easier to just set the AP to that waypoint and relax.

Your description of setting the heading line on the plotter to meet the COG to a waypoint is exactly setting the AP to the waypoint. I don't see much advantage of doing this manually (and continually making adjustment), and both ways require one to adjust sails and stay on watch. You might think you are active in the steering, but allowing an AP to partially steer is a strange line to draw between full AP steering vs. full hand steering.

One advantage of steering to a waypoint/route vs only to a compass is making a course change short handed. When steering to a waypoint, and that waypoint has been reached and the boat needs to go to the next, the AP alarms that it wants to turn to the next waypoint and one pushes the "OK" button, then one is free to adjust sails while the AP turns and locks onto the new course. No juggling tasks between setting the course and adjusting the sails.

Another advantage of having the ability to integrate a GPS (regardless of if it is used) is if the compass goes down, the AP can use COG as heading and continue to work. Otherwise, one has lost their AP.

Having wind integration opens up much more functionality and usefulness.

Mark
 

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For example, motoring - particularly in a cross current. Yes, one can sit at the AP continually adjusting the course to meet a waypoint, but it is much easier to just set the AP to that waypoint and relax.

Your description of setting the heading line on the plotter to meet the COG to a waypoint is exactly setting the AP to the waypoint. I don't see much advantage of doing this manually (and continually making adjustment), and both ways require one to adjust sails and stay on watch. You might think you are active in the steering, but allowing an AP to partially steer is a strange line to draw between full AP steering vs. full hand steering.

One advantage of steering to a waypoint/route vs only to a compass is making a course change short handed. When steering to a waypoint, and that waypoint has been reached and the boat needs to go to the next, the AP alarms that it wants to turn to the next waypoint and one pushes the "OK" button, then one is free to adjust sails while the AP turns and locks onto the new course. No juggling tasks between setting the course and adjusting the sails.

Another advantage of having the ability to integrate a GPS (regardless of if it is used) is if the compass goes down, the AP can use COG as heading and continue to work. Otherwise, one has lost their AP.

Having wind integration opens up much more functionality and usefulness.

Mark
I observe the track which will deviate from a straight course because of current and making leeway for example. But I can find the course which essentially steers the direct line... and yes over time I AM making some minor course corrections. I do this when sailing or trim... Sailing is an ACTIVE process.
Also key to how I navigate/steer with the AP is I see where the heading will take me... over hazards, thin water and so on. The GPS waypoint doesn't know what its course passes over.
I think the KEY word is that I am ACTIVE with respect to steering evaluating the chart and weather/sea conditions constantly and accounting for them. But the level of activity is minor... If there is a cross current in a few minutes I can see how the set course needs to be corrected... And observe is KEY... I need to consider traffic and make adjustments accordingly. A set waypoint ignores this. When a boat is crossing my path I often steer to its stern.. which changes as he moves across my path... The skipper can see that I am taking a decision to avoid a collision and not even pass in front of his bow.
A waypoint may be many miles away... and steering to one ignores the local environment.
As I mentioned I often enter waypoint coordinates and my instruments are providing data for that point relative to my present position.
So let's say I am moving in a strong cross current and the waypoint is 90°. I will turn the course dial and observe what is the COG is and make it 90°... I may actually be heading 100° but set to 90° by the current... So I can sail almost perfectly straight course (shortest) to my destination / "waypoint". Any typically I have to do a lot of "dodging" of boats... and that is no problem the way I use the AP. This shows the difference between the course line and the heading line.
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Looks like I can pass safely between the buoy "15" and buoy "2". Track is light magenta line
 

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I observe the track which will deviate from a straight course because of current and making leeway for example. But I can find the course which essentially steers the direct line... and yes over time I AM making some minor course corrections. I do this when sailing or trim... Sailing is an ACTIVE process.
Also key to how I navigate/steer with the AP is I see where the heading will take me... over hazards, thin water and so on. The GPS waypoint doesn't know what its course passes over.
I think the KEY word is that I am ACTIVE with respect to steering evaluating the chart and weather/sea conditions constantly and accounting for them. But the level of activity is minor... If there is a cross current in a few minutes I can see how the set course needs to be corrected... And observe is KEY... I need to consider traffic and make adjustments accordingly. A set waypoint ignores this. When a boat is crossing my path I often steer to its stern.. which changes as he moves across my path... The skipper can see that I am taking a decision to avoid a collision and not even pass in front of his bow.
A waypoint may be many miles away... and steering to one ignores the local environment.
As I mentioned I often enter waypoint coordinates and my instruments are providing data for that point relative to my present position.
So let's say I am moving in a strong cross current and the waypoint is 90°. I will turn the course dial and observe what is the COG is and make it 90°... I may actually be heading 100° but set to 90° by the current... So I can sail almost perfectly straight course (shortest) to my destination / "waypoint". Any typically I have to do a lot of "dodging" of boats... and that is no problem the way I use the AP. This shows the difference between the course line and the heading line.
View attachment 143543
Looks like I can pass safely between the buoy "15" and buoy "2". Track is light magenta line
I get it. It is exactly how things look when the AP is set to a waypoint. The only difference is that one is not continually making adjustments to the heading to maintain that course to the waypoint. Like I said, it is a strange distinction, and to me it isn't any more "active" than letting the AP continually make these changes.

When our AP is set to a waypoint, the COG and heading lines are also on our plotter. They overlap pretty closely, but one still sees what is happening. If you are on top of things with your system, the heading and COG lines would also be overlapped pretty closely. I don't understand why one would plot a COG over a hazard or thin water, nor how the heading line would show this where the COG line does not. The heading doesn't understand hazards anymore than the COG does.

If you were really serious about being "active", you wouldn't use the autopilot at all. Again, a strange distinction of where to draw a line there - and an imaginary line at that, since there really isn't any difference in activity beyond occasionally turning a knob a little bit, nor any difference in awareness of what is going on environmentally. Not sure why you think that setting the AP to a waypoint is like going below and taking a nap. It is more like not continually holding the jib sheet in your hand, and instead having confidence that the winch or clutch will hold it so you can walk away.

In your example above, the difference in AP operation would be that if something went pear shaped that required and diverted one's attention as those buoys were approached, the AP steering to a waypoint would safely steer through them, while the one steering to a compass might put the boat on the rocks.

Mark
 
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