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Thread: Sharing Autopilot discussion from other side of the pond...

  1. #1
    Join Date
    Mar 2009
    Albany, CA

    Default Sharing Autopilot discussion from other side of the pond...

    Living in The Netherlands and having bought a new boat (Seascape 27) I asked about autopilot preference for this light displacement boat. I found the discussion interesting and thought I would share it here.
    btw Andraž Mihelin is one of the founders of Seascape and well known mini 6.50 sailor

    Seascape 27 What autopilot are you using for shorthanded racing?

    Raymarine +6

    B&G +4

    NKE +2

    Other +1

    Dirk Husselman: Thanks for the info. I'm surprised only 2 NKE out of the 9 replies. How happy are the owners with Raymarine? I assume using EV-200 sail autopilot? Do you use it under spinnaker? True wind mode?

    Kenny Lawrence: Ah, the computer is b&g nac-2 but the ram is raymarine

    Dirk Husselman: Does the B&G nac-2 has auto AW to TW mode? I thought the H5000 has the TW mode comparable to NKE. I'm leaning towards NKE but open to other systems

    Kenny Lawrence: Yes, NAC-2 or -3 has wind mode, and you either use Auto selection (it uses AWA below a certain value, I think maybe 60 TWA or so, and it uses TWA for anything higher - I haven't paid enough attention to know exactly when it makes the transition, but it...See More

    Lukas Steuerwald: NKE Computer and Raymarine ram, to be precise

    Philipp Lenzlinger: Raymarine EV autopilot computer and linear drive in an otherwise B&G system. At the time EV-1 was the best and most easily calibrating 9-axis gyro. Today I‘d probably go for all B&G (perhaps stay with the raymarine linear drive). B&G automatically switches from AW mode to TW mode depending on upwind or downwind leg. I use the autopilot downwind mainly in heading mode to prepare for maneuvers (if at all).

    Kenny Lawrence: do you know when B&G transitions between AWA and TWA? How do you define downwind leg for this purpose?

    Philipp Lenzlinger: Not 100% sure, but you can most probably configure yourself: at a certain TWA (say115°) it will switch TW mode.

    Kristian Hajnsek: NKE system is very good but more demanding for user. ONe need to dedicate a bit more time to understand all the settings and quirks, but then the performance downwind or reaching is surprisingly good.
    If one needs to sail solo for longer time, TW mode is best thing to avoid wrapping spi around forestay...

    Kenny Lawrence: I am intending to try the 3d motion sensor from B&G on my next boat (supposed to factor in pitch/roll/yaw due to wave action)

    Philipp Lenzlinger: Yes, this is why I think there is no advantage of the Raymarine EV-1 anymore.

    Kristian Hajnsek: NKE Gyropilot does that as well as Raymarine SmartPilot. They all use gyro unit to do that.

    Vilhelm K. Vardřy: The Raymarine don't compensate the movement of the windwave/mast though. In B&G with the 3d motion sensor and hercules cpu you can input the mast height in order for it to remove these movements from the wind sensor.

    I know NKE can do the same, but if I recall correctly they have a IMU sensor in the wind wave to do this. And *I think* this is only in the most expensive wind vane they have.

    Philipp Lenzlinger: Raymarine EV-1 apparently has a self learning algorithm to compensate boat movement. I think the advances in gyro sensitivity (and drop in price of 9-axis snsors) in the past two or three years have made it irrlevant which system you choose. B&G and NK...See More

    Joachim Hasler: I use B&G H5000 (Hercules CPU) with a Raymarine linear drive (as suggested by Andraz).

    Andraž Mihelin: Hi all - as Phillip pointed out new electronics made the difference between systems smaller - Gyros are now part of all of them which means surfing downind is possible with all of them. TWA data is still the holy grail and for that you will be paying premium of NKE or B&G H5000 systems. Keep in mind the TWA is not so cruicial for autopilot function on amateur racing level. The exact TWA helps you play the sailchanges according to the sail selection chart, follow the windshifts and understanding how far of your targets are you. BUT and it it a big BUT - you have to calibrate it regulary. Raymarine is giving you average data with no effort from your side. NKE and B&G will give you excelent data with some effort (calibrating after every assembly and also ideally before every race) but shitty data if no effort is alocated. So it all comes down to how much Geek is still in you. If you don't often open up "advanced settings" in you everyday software you are most likely going to be happier with Raymarine

    Philipp Lenzlinger: Perhaps one last comment going back to the original question about which system to use: I am pretty happy with my system (B&G Triton and Vulcan, Raymarine EV-200 AP). If I wanted to improve perfomance or the quality of data, I'd probably invest in a racing B&G wind vane which sits 2 to 3 feet above the mast top.

    Andraž Mihelin: Racing windwane will be useless with basic system - you need upwash correction tables + some other software gimmicks to make it work...

    Joachim Hasler: software gimmicks... great description!

    Philipp Lenzlinger: Didn't know that. Doesn't the fact that it its higher, and therefore in cleaner air, make it more accurate?

    Philipp Lenzlinger: Joachim Hasler how complicated is it, actually, to calibrate our system?

    Joachim Hasler: Philipp Lenzlinger It takes a lot of time and at the end you can't be sure that things works correctly without a reference. But as a technical (and software) guy I love to do that. For guys without technical background I suggest to use standard technique.

  2. #2
    Join Date
    Jan 2015
    San Francisco Bay


    What are the definitions of TWS and TWA for each of these systems? (Some do it relative to the water and some to ground. Never sure which does what.)

  3. #3
    Join Date
    Jan 2013
    Montara, CA


    Thanks for this, Dirk! I'm gonna need to get my Geek on. Put me down as +1 for B&G, too. There is some good info here that I need to digest further while I have the manual opened on my lap. After doing the LongPac last summer in a fairly new-to-me-then B&G AP and gyro compass with an old, but sturdy hydraulic ram, I was amazed at its performance handling in some really nasty conditions (confused sea state, big beamy swell, steady 30 knots wind). Kynntana is a heavy boat so maybe that had something to do with it, but I've heard these things come with smart "brains" - or at least they're smart with the proper inputs...

  4. #4
    Join Date
    Nov 2010
    Discovery Bay, CA


    Say what you will about Raymarine, my EV1, ACU 200 and linear drive operated flawlessly for 4800 miles. Downwind performance could be improved and i did not check windvane mode. But that's software and, to me, mechanical and electrical reliability are the holy grail. Software you can fix later.

  5. #5
    Join Date
    Sep 2007
    San Francisco Bay Area


    As a complete aside... How do you like the Seascape 27? Tha't the smallest boat you've had in a long time!
    Last edited by AlanH; 09-14-2018 at 01:02 PM.
    1968 Selmer Series 9 B-flat and A clarinets
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