Autopilot Choice

[Dockhead]

I am finishing the specification for my new electronics and am a bit stumped by the autopilot.

My main network will be built around B&G Zeus plotters (which is the Simrad NSE with added sailing functions) and a B&G/Simrad 4G radar.

I have used the Simrad/Robertson autopilots and loved them. So my first impulse is to use the AP28 controller with the AC42 course controller.

I have looked at the B&G autopilots and can't figure them out. The H3000 control head seems more primitive than the AP28, and the Triton pilot looks like it is altogether intended to be used with the plotter as the control head (which I don't like).

Does anyone have any insights into the plusses and minusses of these various pilots?

[colemj]

We have the Simrad AP24/AC42 and the B&G Triton T41 with the Triton AP control pad.

The autopilot is really the AC42 computer - the control heads are just multifunction displays with buttons to control the AC42. The displays also show wind, nav, speed, depth, temperature, etc data along with interfacing to the autopilot. We sailed for 6 months with the AP24 being our sole data display for all the instruments.

All of them are very good. The (brand new) Simrad control head looks very old and dated next to the Triton, but is still a full MFD and AP controller - just B&W and numerical only. The Tritons are simply stunning.

The Triton T41/AP pad combo completely controls the Simrad AC42 for all normal sailing usage. It will also perform all of the setup and calibration procedures. However, it does not include many of the advanced functions of the AP24/28, like steering to a depth contour, steering geometric courses, etc. For sailing, these functions are pretty useless anyway.

The sailing usage shortcoming is that the Triton currently only allows the modes "Compass", "Wind", "Navigation" and "Power Steer". So the modes "No Drift" and "Wind/Nav" are missing (along with the fishing/powerboat functions listed above). I don't know why, but suspect that it is because the Tritons are very new and functions were left out to bring it to market quicker and that B&G wanted to keep the AP pad functionality simple.

I strongly suspect that the next version of the Simrad AP control heads will be very Triton-like, and that the current Triton instruments will gain more AP control and even be issued as a B&G autopilot system.

Mark

[Dockhead]

Well, the AP28 control head is a horse of a different color. AP28-Autopilot - Simrad Yachting

That's the one I have experience with, and I like it. It displays what I need to know -- heading, AP setting, rudder position, and has really good controls with a knob. It doesn't seem to me that there is any B&G analogue.

[colemj]

Yes, I am very familiar with the AP28 because I seriously considered it vs the AP24 - it is exactly the AP24 with a control knob and a single page that displays a very crude wind angle and compass graphic instead of just numerical data on the AP24. There are no other functional or display differences between the two.

I was answering your question about anyone having experience with the two systems and giving the differences/similarities and advantages/disadvantages among them, as you asked for. If you like your AP28 and only want that again, then you didn't need to ask your question.

The B&G Triton 41 displays everything the AP24/AP28 displays - rudder position, course, heading, DTW, ETA, TTG, AP mode, etc. It does so with a much more updated look and feel and has additional MFD capabilities the AP24/28 lack. It lacks some functionality as I described above and requires the control pad to work as a true autopilot and not just a display. It does not have a course knob like the AP28 - you need to use the dodge buttons on the control pad like the AP24.

As I said above, I strongly suspect the next version of the Simrad AP24/28 to be similar to the Triton and the Triton to gain more AP functionality (why else would it contain the complete Simrad setup, commissioning and calibration software and most of the control functions?). The B&G AP computer has already transitioned to the Simrad one.

Along the same lines, Simrad is already transitioning their 4.5" MFD's to Triton-style ones and, as you pointed out, the Simrad and B&G chartplotters are identical with only software features differentiating them.

Mark

[Dockhead]

Originally Posted by colemj

Yes, I am very familiar with the AP28 because I seriously considered it vs the AP24 - it is exactly the AP24 with a control knob and a single page that displays a very crude wind angle and compass graphic instead of just numerical data on the AP24. There are no other functional or display differences between the two.

I was answering your question about anyone having experience with the two systems and giving the differences/similarities and advantages/disadvantages among them, as you asked for. If you like your AP28 and only want that again, then you didn't need to ask your question.

The B&G Triton 41 displays everything the AP24/AP28 displays - rudder position, course, heading, DTW, ETA, TTG, AP mode, etc. It does so with a much more updated look and feel and has additional MFD capabilities the AP24/28 lack. It lacks some functionality as I described above and requires the control pad to work as a true autopilot and not just a display. It does not have a course knob like the AP28 - you need to use the dodge buttons on the control pad like the AP24.

As I said above, I strongly suspect the next version of the Simrad AP24/28 to be similar to the Triton and the Triton to gain more AP functionality (why else would it contain the complete Simrad setup, commissioning and calibration software and most of the control functions?). The B&G AP computer has already transitioned to the Simrad one.

Along the same lines, Simrad is already transitioning their 4.5" MFD's to Triton-style ones and, as you pointed out, the Simrad and B&G chartplotters are identical with only software features differentiating them.

Mark

I've been reading the manuals, and I have now figured out and have been won over to the Triton as a pilot control. I don't need the missing pilot functions (and if I did, I guess I could evoke them from the Zeus MFD).

[Dockhead]

Well, my thinking has evolved yet further, but into a somewhat uncomfortable zone, far beyond my previous ways of working with pilots.

I can now buy a Simrad NSS7 MFD for less than $1000 (there's a $300 rebate going on). It's not much more expensive, and doesn't take up that more space, than the Triton plus control pad.

I have pored over the manuals, and the pilot control integrated into the MFD seems to be really well thought out to be used as the primary or sole means of controlling the pilot. It has a dedicated hardware button to engage and disengage the pilot, and dedicated LEDs to show the pilot status.

What do I need to know from the pilot controller? Heading, pilot status, heading ordered (on regular auto mode), wind angle ordered (on wind following mode), rudder angle. I think I can get all this data on a data bar in the NSS, while still being able to use the display for other purposes.

So why wouldn't I prefer a second MFD - which is SO versatile - to a dedicated pilot control head? I wonder if anyone is going without a dedicated pilot control, and can share impressions?

[colemj]

Don't see any real requirement for a dedicated pilot control unit. The main consideration is usually fitting a space next to the helm for it, where the small pilot controllers work in most cases. Also, one may wish to have a different brand MFD than the AP, or not use a MFD at all.

Maybe a good compromise is the MFD at the helm for pilot control and a Triton control pad at the nav station for remote control (ie, no Triton display)? Unless the second MFD also has pilot control functions - I wasn't clear on that.

Mark

[S/V Alchemy]

Originally Posted by colemj

Don't see any real requirement for a dedicated pilot control unit. The main consideration is usually fitting a space next to the helm for it, where the small pilot controllers work in most cases. Also, one may wish to have a different brand MFD than the AP, or not use a MFD at all.

Maybe a good compromise is the MFD at the helm for pilot control and a Triton control pad at the nav station for remote control (ie, no Triton display)?

I like this approach. I am opting (for the moment) for a simple Comnav AP that controls hydraulics. My job is to supply input derived from entirely separate plotting, both GPS and traditional.

I find this approach is more robust and straightforward. Not necessarily better, but suitable for me. I would no longer program an AP to sail to a waypoint than wear my sunglasses at night, so I need to figure headings to get 'near enough', after which I would hand steer if, for instance, I wanted to be five miles away from a known reef or shore. Again, not to everyone's taste or preference.

I'm no Luddite. I love AIS and RADAR and look forward to consulting them as needed and gladly. I do not, however, feel an AP should do more than integrate with a compass and keep the boat pointed in the right direction.

[Dockhead]

Originally Posted by S/V Alchemy

I like this approach. I am opting (for the moment) for a simple Comnav AP that controls hydraulics. My job is to supply input derived from entirely separate plotting, both GPS and traditional.

I find this approach is more robust and straightforward. Not necessarily better, but suitable for me. I would no longer program an AP to sail to a waypoint than wear my sunglasses at night, so I need to figure headings to get 'near enough', after which I would hand steer if, for instance, I wanted to be five miles away from a known reef or shore. Again, not to everyone's taste or preference.

I'm no Luddite. I love AIS and RADAR and look forward to consulting them as needed and gladly. I do not, however, feel an AP should do more than integrate with a compass and keep the boat pointed in the right direction.

What about wind following mode? Single most useful autopilot mode IMO.

[S/V Alchemy]

If you mean "vane mode", where the AP corrects to maintain a sail angle relative to the wind as per mechanical inputs from the wind instrument, sure, that can be useful if one is sufficiently alert or the wind is variable within a narrow enough range.

Most modern autopilots have this, and even my antique Autohelm 1000 tillerpilot can do it, I think.

I didn't include it as I have a completely separate steering system from any controlled by an AP. It involves putting a tiller on the tiller head, hooking up the wind vane control lines, and then turning a lever to bypass the hydraulic steering and shutting off the AP. Zero amp helming is a consideration for us on passage. I am happy when the engine is running or when the wind genny is pumping in amps to the batteries to use AP and hydraulics to steer, although it seems that vane and AP look as effective the longer you sail, as argued in this fairly famous article:

Windvane, Autopilot, steering systems

[44'cruisingcat]

Originally Posted by Dockhead

Well, my thinking has evolved yet further, but into a somewhat uncomfortable zone, far beyond my previous ways of working with pilots.

I can now buy a Simrad NSS7 MFD for less than $1000 (there's a $300 rebate going on). It's not much more expensive, and doesn't take up that more space, than the Triton plus control pad.

I have pored over the manuals, and the pilot control integrated into the MFD seems to be really well thought out to be used as the primary or sole means of controlling the pilot. It has a dedicated hardware button to engage and disengage the pilot, and dedicated LEDs to show the pilot status.

What do I need to know from the pilot controller? Heading, pilot status, heading ordered (on regular auto mode), wind angle ordered (on wind following mode), rudder angle. I think I can get all this data on a data bar in the NSS, while still being able to use the display for other purposes.

So why wouldn't I prefer a second MFD - which is SO versatile - to a dedicated pilot control head? I wonder if anyone is going without a dedicated pilot control, and can share impressions?

Sounds like a very good idea to me. The NSS is an excellent control head for the pilot. It does everything the normal control head does. If it will fit in the availble space, go for it.

[nhschneider]

We installed the Simrad AP24/AC42 a little over two years ago, connecting it to a Garmin N2K network (Garmin chartplotter, sailing instruments, AIS, depth sounder, sonar, radar, etc) and we love it. Since we installed it, we have sailed over 12,000 miles and since we don't have wind vane steering nor do we care for long periods of hand-steering, it's an essential piece of electronics for us. There are two issues, though, of which I thought you might want to be aware - one trivial and the other potentially serious.

The trivial issue first: Since the N2K network does provide a minimal amount of power, it's possible to have the circuit breaker for the autopilot turned off and still have enough power to bring the display up, indicating that the autopilot is on and fully functioning. But it isn't. There's only enough power to bring up the display and not enough to power the steering mechanism. Circuit breakers will trip and fuses will blow if you're not aware of this. The simple solution is to leave the circuit breaker for the autopilot on all the time.

The second issue we have is that about once every 24 hours, regardless of whether we're under power or sail, the autopilot display goes into alarm mode, it stops steering and says, "Cannot find autopilot computer". Canceling the alarm is easy (press any key) and the normal display returns instantly. Then we re-engage the autopilot and it's fine for another 24 hours or so. All three of us are so used to the problem that we can be back under autopilot control in a matter of a few seconds. I can see the mental gears of those reading this spinning away, thinking, "This guy is an idiot. It's either a wiring problem, an SSB or VHF transmit problem or maybe a refrigerator compressor that cycling that's causing his problem.". First, I'll match my skills at routing, dressing and terminating wires and cables with the most discerning of technicians. For 25 years I owned a low-voltage contracting company and spent way too much time doing it. I've isolated the ground, relocated the related cables away from any high amperage cables or sources. There is no correlation to the use of the SSB (although keying the SSB's mic does send the autopilot into a steering frenzy) or VHF. We have even gone to the extent of shutting down our refrigeration compressors to see if that would cure the problem. It didn't.

I bought a second AC42 but that has the same problem. I have been in touch with Simrad technical support and they want us to ship them the units. Now that we should be staying put in Australia for a while, we'll do just that.

Regardless, I still like the Simrad autopilot very much. Fortunately, our boat balances very well so it makes it easy to get the autopilot dialed in to where there is little correcting that has to be made, under most conditions.

Fair winds and calm seas.

[44'cruisingcat]

Just remember than when you buy the NSS, you'll still need to buy the Simnet cable to go with it.

[Paul L]

I don' t see how you can like an AP that fails to steer at random times. This could easily cause a dangerous roundup or other steering delight.

[44'cruisingcat]

Originally Posted by nhschneider

The trivial issue first: Since the N2K network does provide a minimal amount of power, it's possible to have the circuit breaker for the autopilot turned off and still have enough power to bring the display up, indicating that the autopilot is on and fully functioning. But it isn't. There's only enough power to bring up the display and not enough to power the steering mechanism. Circuit breakers will trip and fuses will blow if you're not aware of this. The simple solution is to leave the circuit breaker for the autopilot on all the time.

The second issue we have is that about once every 24 hours, regardless of whether we're under power or sail, the autopilot display goes into alarm mode, it stops steering and says, "Cannot find autopilot computer". Canceling the alarm is easy (press any key) and the normal display returns instantly. Then we re-engage the autopilot and it's fine for another 24 hours or so. All three of us are so used to the problem that we can be back under autopilot control in a matter of a few seconds.

Interesting. We have the same setup, but if I switch the instruments on and power up the control head without powering up the A/P computer, and I try to activate the autopilot, I simply get a "No autopilot computer" alarm.

So far we've done about 10,000 miles on this pilot, but haven't had the second problem at all.

Maybe they've updated the software?