B&G NAC vs Raymarine Evo200

MiddayGun

Super Anarchist
1,247
493
Yorkshire
OK, so I know this comes up a lot, I've been trawling threads and haven't been able to come up with a good answer.

I've just switched boats to an Elan 362, typical IRC cruiser racer of its day, spade rudder, reasonably heavy (6000kg), its currently got a wheel drive ST4000+ which is 23 years tech, and all the instruments are Raymarine, old school ST60 for the Speed / depth / wind etc connected using the old Seatalk network.

The plotter down below is a more modern ES series and there is also a slave E series plotter at the wheel, and a Seatalk > NG bridge to get all that instrument info to it, so there is N2K backbone with Wind / Speed / SOG etc on it.

I want to upgrade the autopilot to something modern with a proper gyro that can steer the boat properly when conditions aren't so good, I'll be fitting an underdeck drive, but this question is more about the computer.

Given that everything is Raymarine already, the logical choice would be the EVO autopilot, but from trawling through threads on here, a lot don't seem to rate it too highly, especially in challenging conditions.

NKE seems to be the gold standard, but probably more than I want to spend, especially as I'd need to change my sensors as well, same for the B&G H5000.

Which seems to leave the NAC-3 vs the EVO.
The NAC-3 costs a little more by the time you have the keypad and display, but I don't mind that if its genuinely better, in the recent thread one guy said he'd never go Simrad but he liked B&G, but they are the same computer these days. All very confusing.

As I have wind and speed data on the NG network, I can wire the B&G stuff into that and it should be able to read it all as its basically N2K

So does anyone have any real world experience with both of them that they could share?
Is there much difference between the two, or do you need to go the top line stuff to see any improvements?
 

dreamingwet

Member
371
128
The NACs and the 5000 share the same base code, some of the functions on the 5000 are not enabled on the NACs. But still an amazing pilot.
We used a NAC2 in a J122, and it sailed the boat in the worst possible conditions, A3 big rolling and breaking seas at 100-130 degrees surfing 14-16knts.

Like with every pilot trimming is key.
In my boat I have a H5000 and NAC2 as backup.
Without knowing what type of sailing you do, If you can afford I would do the 5000, then NAC and then the EVO.
But I do not have much experience with the latest Raymarine.
 

MiddayGun

Super Anarchist
1,247
493
Yorkshire
@dreamingwet Interesting that you got away with using the NAC-2 on the a J/122.

Considering its a bigger & heavier boat than mine, and will probably see similar or larger rudder loads and I would guess needs to be steered a little more actively, that makes me think I can maybe get away with the NAC-2.

The sailing I need it for is cruising, often short and single handed, if it can steer when the winds up with a quartering sea & the boat sailing surfing away then I'd be good. Even better if it can cope with spinnaker runs on true wind direction mode.

The racing we have around here is all crewed, so we can't use it for that anyway.
 

dreamingwet

Member
371
128
I am not saying that weight is not to be considered; but in my opinion, balance is the most important factor in an autopilot, then the rudder’s aspect ratio, then weight.

At no point I would have considered that I am getting away with anything using the NAC2, the boat even came with the Raymarine electric ram, I was going to replace with a L&S, but the ram worked like a dream.
I might just send the Raymarine ram to get refurbished and put it back on
 

Plumbean

Member
334
78
Check compatibility with your drive unit as well. I was going back and forth between the NAC2 and NAC3 for my boat (34 footer, 13,000 pounds) until I realized that the NAC2 is not compatible (at least according to B&G's documentation) with the DD15 drive unit i was installing. The NAC3 can handle a much higher output requirement than the NAC2 (30 amps v 8 amps). I also have a skeg hung rudder so likely higher loads than a spade.
 

JC522

Member
186
61
USA
I've used Ray autopilots on my 38 and 45 foot boats in the last 15 years. The Ray gear does a great job even in 8 to 10 foot short-cycle quartering seas with too much canvas. I never have to hand steer the boat. Below are a couple examples where I'm totally trusting the autopilot to do the steering in those 8 to 10 footers while I'm up at the companionway taking pictures.

20180717_144401b.jpg


IMG_2982b.jpg
 
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b393capt

Anarchist
I think there is room for confusion and attributing too much to a straight-up comparsion of the five autopilots mentioned above, under sail, without considering the wind sensors.

A good autopilot can be inhibited by bad wind information, especially when sailing a set number of degrees off the wind. For example my Ray autopilot originally did poorly under A2 spinnaker on my previous 39 foot Beneteau cruising sailboat, which was remedied by placing a PB200 Airmar Ultrasonic Weatherstation on top of the mast replacing Ray's mechanical sensor. With the better wind measurement, that same autopilot (from 2007), was able to stay in the groove upwind and steer my boat competently downwind with the A2.

Read about this specific experience here in this PANBO article, skip down five paragraphs to upwind and downwind, with the Ray autopilot circa 2007 and PB200 wind instrument.

An absolute bonus of the PB200 was its far better ability to measure and report wind direction. Just the wind filling the A2 and shocking the mast, would start an oscillation of the autopilot that did not happen when using the PB200. Astounding improvements in autopilot performance was noticeable upwind and downwind, as I wrote back in 2009.

Does Ray have features in their Autopilot to compensate for boat motion, heel, etc. when steering to the wind now in 2023? If not, that could be a big comparison point when reading experiences using one autopilot or another, as B&G certainly has compensation in some boat installs.

In combination with my 39 foot cruising sailboat at the time of PB200 article, the PB200 was a big improvement to my autopilot performance as the the PB200 was filtering out much of the wind measurement noise when my boat went up and down through the waves that was simply not available additively to my Ray wind sensors at the time. The PB200 used multi-axis sensors much like our modern-day compasses have, and corrected for wind direction based on the angle of the boat's heel. My 2007 Ray autopilot did have a rate of turn sensor built in, but that was it.

The Ray EVO compass, brings in all that multi-axis goodness, but I have no inside knowledge to know if anyone's autopilot uses that to the extend the PB200 did to correct for wind measurement.

Sailing an entirely different boat, a J/109, I noticed immediately that the B&G mechanical wind was not as good as I experienced with the PB200. Once I added the H5000 and motion sensor to my used J/109, I found (as near as I could tell), the same or possibly better wind measurement I had with the PB200 on my former cruising sailboat, so clearly the wind information in each situation (mechanical or ultrasonic) is enhanced by software correcting measured wind using multi-axis compass, accelerometers, and heel measurement enabling the autopilot to perform better.

I hope you take away from the above, that the varied individual experiences you read on SA and elsewhere with different combinations of autopilot, boat, and weather are likely more of a testament to the quality of the wind measurement than the autopilot brains.

If anyone wants my advice, I would say for these three use cases ...

Cruising Sailboat: Buy one of those Airmar ultrasonic weather stations, especially if you want to see a huge performance from your autopilot under sail, upwind plus downwind spinnaker sailing. Aside from autopilot improvement, having a great wind sensor (combined with a clean and calibrated speed through water sensor) can provide great true wind information and feedback to amateur sailors as they trim sails, taking some (not all) of the mystery out of why good trim one day doesn't work on others. Your choice of autopilot just won't matter, they are all very good especially Raymarine if sized and installed properly.

Racing Sailboats, autopilot illegal: When you or your crew are delivering the sailboat between races under sail, trimming just leisurely with beer in hand, you will go quite a bit faster with improved wind information steering your existing autopilot through each wind shift. The H5000 Hercules with the B&G wind sensor on a tall wand, I believe is among the best, helping a Ray, B&G, and my old Simrad Autopilot I currently use. Bonus, when racing the better wind information will improve your understanding of your crews performance. Bottom line, your choice of autopilot won't matter unless you are in seriously bad weather while not racing.

Racing Sailboat with autopilot allowed, e.g. 2 handed: I am hesitant here, I have no experience. I am not sure, but I suspect that B&G's careful attention to all things sailing, for example, estimation of set & drift, might very much give the H5000 autopilot an edge over Raymarine.

Note the Airmar 2009 PB200, has been replaced by later models of Airmar Weather stations like the 200WX with accelerometers and heel correction.

Was this helpful? To follow what I write about marine electronics:
* In practical sailor magazine, there is a past article on my B&G H5000 setup (sans autopilot, which is Simrad) and a recent Furuno SCX20 compass is really amazing! I would recommend the Furuno for cruising and racing sailboats equally, especially if you have a great wind sensor and you keep your speed through water sensor clean and calibrated.

* Check out Panbo at the link above for multiple past articles on marine electronics, and/or read my articles in practical sailor magazine. Also there is this article about installing the PB200:

And, if you are in the healthcare industry, follow me on LinkedIn at Dan Corcoran or my company website SafeQual dot net, as my team, and I work to constantly improve our enterprise software for hospitals, enabling their safety, quality, and risk departments to work better and with more automation in their pursuit of clinical quality.
 
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penumbra

Member
107
35
WLIS (ish)
Check compatibility with your drive unit as well. I was going back and forth between the NAC2 and NAC3 for my boat (34 footer, 13,000 pounds) until I realized that the NAC2 is not compatible (at least according to B&G's documentation) with the DD15 drive unit i was installing. The NAC3 can handle a much higher output requirement than the NAC2 (30 amps v 8 amps). I also have a skeg hung rudder so likely higher loads than a spade.
If the conversation is NAC-2 vs NAC-3, it's about the electrical load they can handle. As I recall, if you have a type 2 drive, you need the NAC-3. We just replaced a nearly 20 year old Ray setup with B&G, keeping the old type 2 drive. It's the same drive I've seen on every 35+ ft boat for the last 15 years.
 

MiddayGun

Super Anarchist
1,247
493
Yorkshire
Well there's significant difference in NAC-2 / 3 pricing, though I'm sure the computer is the same.
If the NAC-2 can drive my autopilot drive, then I would probably go B&G as the system is comparable in price to the EVO.

Naturally its almost impossible to find like for like comparisons.
So I think first I need to determine my drive unit (as I may be able to buy something that will integrate directly into the steering pedestal.) Once I've determined that, then it should be clearer what options I have.

@b393capt I'm not sold on those Airmar transducers, I skippered a CTV with one for many years, and while it worked well, I can't see it was better than the masthead unit I had from B&G on my boat.
 

DDW

Super Anarchist
7,144
1,554
My Raymarine will steer in any conditions, upwind, downwind, large quartering seas, dead down wind in large seas - with complete reliability and very good course keeping. The big jump in performance came on with solid state gyros and machine learning, around 2008 or so, then smaller progressive improvements. I've had 4 generations of Raymarine course computer and each is better than the last. It used to be said that the autopilot can steer better than a human, and I always found that to be BS - until gyros. Now it does the same thing I would do, but faster.

You can separate two aspects, the course computer's ability to generate steering corrections, and the drive's capability of executing those corrections. They needn't be the same brand, but both have to do their job. Any course computer with properly implemented gyros is way better than one without, once that is done I think the difference between brands is small. It is said that NKE are a bit better on fast boats downwind when steering by wind, this is due to the true wind calculations being faster or more accurate.
 

inneedofadvice

Super Anarchist
1,620
294
Sarnia
My Raymarine will steer in any conditions, upwind, downwind, large quartering seas, dead down wind in large seas - with complete reliability and very good course keeping. The big jump in performance came on with solid state gyros and machine learning, around 2008 or so, then smaller progressive improvements. I've had 4 generations of Raymarine course computer and each is better than the last. It used to be said that the autopilot can steer better than a human, and I always found that to be BS - until gyros. Now it does the same thing I would do, but faster.

You can separate two aspects, the course computer's ability to generate steering corrections, and the drive's capability of executing those corrections. They needn't be the same brand, but both have to do their job. Any course computer with properly implemented gyros is way better than one without, once that is done I think the difference between brands is small. It is said that NKE are a bit better on fast boats downwind when steering by wind, this is due to the true wind calculations being faster or more accurate.
I think the faster calculations is the key. I have an Evo AP with all Raymarine instruments and I can feel the changes in wind speed and direction before it shows up on the instrument. It’s a wired unit that is routed to an itc5 that I believe converts analog info to stng/nmea2000. While the system works well I alwywonder if that’s the weak link.
 

DDW

Super Anarchist
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That can't take much time, even in last century tech. More likely they have a smoothing algorithm that is defeating to some extent what we sailors want to accomplish. I guess it is possible the itc5 only transmits wind every second, which is a long time. You could put the MFD in diagnostic mode and look at the incoming N2K datagrams to see. My Raymarine wind is directly connected to N2K and I don't notice a delay, though there is certainly some algorithmic dampening.
 

inneedofadvice

Super Anarchist
1,620
294
Sarnia
That can't take much time, even in last century tech. More likely they have a smoothing algorithm that is defeating to some extent what we sailors want to accomplish. I guess it is possible the itc5 only transmits wind every second, which is a long time. You could put the MFD in diagnostic mode and look at the incoming N2K datagrams to see. My Raymarine wind is directly connected to N2K and I don't notice a delay, though there is certainly some algorithmic dampening.
Interesting. About a second delay is what I would have guessed. Which is a surprisingly long time in that situation. What type of wind instrument do you have? My Raymarine wind and 810dst through hull both go through the itc5.
 

DDW

Super Anarchist
7,144
1,554
The wind is from about 2007, ST70 instruments, I don't see any documentation on it now at Raymarine. The wind wand looks the same as what they sell now, it is connected to a box that connects to the backbone. This predates the itc5 by some years.
 

El Borracho

Bar Keepers Friend
7,715
3,635
Pacific Rim
Interesting. About a second delay is what I would have guessed. Which is a surprisingly long time in that situation. What type of wind instrument do you have? My Raymarine wind and 810dst through hull both go through the itc5.
Smoothing data always causes a delay. A phase shift is inherent inthe math. Impossible not to, no matter how fast the computation. Digital displays (yuk) are always smoothed so to avoid an unreadable blur of digits. Mechanical needles displays are damped and delayed by the mass of the mechanism. Same for the masthead sensor.

One second is too long.
 

colemj

Member
51
26
We have both a NAC3/RF25/Precision 9 and an EVO1/ACU400/RM rudder reference on our boat. They share network data for wind, STW, COG, SOG, Nav Data, (etc) but are independent otherwise. They use identical, but separate, drive units.

The NAC3 system performs better than the EVO system in general. This mostly shows up in higher precision steering, and a faster response to sudden changes. The EVO system "hunts" more than the NAC3, and does not have the ability to learn sea and response conditions as well as the NAC3. The EVO requires frequent manual dialing in performance to perform at the same level the NAC3 does automatically. The rougher the conditions, the larger the performance difference. I suspect this is all due to differences in steering algorithms (software), since the specs on the compasses, rudder feedbacks, and motor control circuits are pretty much the same, and all other data are shared.

Having said that, it is only a matter of degree. Both are good AP's, and the EVO is lightyears ahead of the previous RM S3 system it replaced. However, it is a step behind the NAC3.

If you are looking for the ability to control from the plotter, you will need to stay with the same manufacturer as the plotter. This doesn't matter to us, and neither of the units can be controlled by our plotter. I'm speaking of actual control like auto/stdby, dodge, modes, etc - both take navigation data from any plotter and can steer to waypoints and routes.
 



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