NMEA2K woes

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   Does anyone else have issues with their N2K bus?In particular, the mast-top wind sensor?

My 415 has the older B&G sensor that runs an N2K cable all the way to the top of the mast.  It periodically loses connection, and the only fix is to literally unplug and replug it at the junction at the base of the mast.  It's common enough that I moved it over to one of the overhead lights, and tied a small string to the light clip.  So I can pull the light out, pull on the string, and get the SIMNET 3 position junction through the light hole, pull the connector and reseat it, and then the wind sensor signal comes back!

They originally had a terminator in the last position of that junction, and it was supposed to be the special one with a capacitor, that i took great pains to find and install (thinking that was the culprit).  Alas, no improvement.

It was particularly annoying in heavy seas and 25+kt winds as it was dropping out every 5 min or so, which was particularly fun to go and do the above operation while the boat is pitching and rolling.

do others have this issue?  it's bad enough that i'm considering stepping the mast this winter and replacing it with a new (non N2K) sensor like the 310 (which curiously does not have the n2k go all the way up the mast)...

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SimonGH Members Profile Send Private Message Find Members Posts Add to Buddy List Commander Joined: 08 September 2021 Location: CT Status: Offline Points: 124	Post Options Post Reply Quote SimonGH Report Post Thanks(0) Quote Reply Topic: NMEA2K woes Posted: 07 September 2025 at 16:17
	Does anyone else have issues with their N2K bus? In particular, the mast-top wind sensor? My 415 has the older B&G sensor that runs an N2K cable all the way to the top of the mast. It periodically loses connection, and the only fix is to literally unplug and replug it at the junction at the base of the mast. It's common enough that I moved it over to one of the overhead lights, and tied a small string to the light clip. So I can pull the light out, pull on the string, and get the SIMNET 3 position junction through the light hole, pull the connector and reseat it, and then the wind sensor signal comes back! They originally had a terminator in the last position of that junction, and it was supposed to be the special one with a capacitor, that i took great pains to find and install (thinking that was the culprit). Alas, no improvement. It was particularly annoying in heavy seas and 25+kt winds as it was dropping out every 5 min or so, which was particularly fun to go and do the above operation while the boat is pitching and rolling. do others have this issue? it's bad enough that i'm considering stepping the mast this winter and replacing it with a new (non N2K) sensor like the 310 (which curiously does not have the n2k go all the way up the mast)...

S&J Members Profile Send Private Message Find Members Posts Add to Buddy List Admiral Joined: 30 August 2014 Location: Perth WA / Med Status: Offline Points: 1371	Post Options Post Reply Quote S&J Report Post Thanks(0) Quote Reply Posted: 10 September 2025 at 06:59
	This generation of MHU had known issues around 2015/16. I had 2 replaced under warranty until I got a good one. They seemed susceptible to static in thunderstorms. I believe these issues triggered the new model (WS310) which removes the complex electronics from the mast head and instead has a box at the foot of the mast to convert the signal to N2K. Or you can go for the wireless option. I can't tell you how to fix your existing transducer, but do think that a newer model will resolve your issues.
	H458 #159 Primal Mediterranean cruising

SimonGH Members Profile Send Private Message Find Members Posts Add to Buddy List Commander Joined: 08 September 2021 Location: CT Status: Offline Points: 124	Post Options Post Reply Quote SimonGH Report Post Thanks(0) Quote Reply Posted: 10 September 2025 at 12:12
	Yes, it sure seems that way! The number of things needed on the mast are piling up, so I think the plan will be for a replacement of the MHU & associated wiring this winter when it's stepped. I'm not sure about wireless - I wish this was one item that wasn't "economized" - I want bombproof connectors and a robust cable so it's never an issue. Not sure why that's so hard to find these days... every boat i've had, including brand new ones, have marginal MHUs (or installs). Cables that start having intermittent connections, units that get waterlogged, etc. I have a new WS310 from my last boat's saga still in the box. So I will give it a go and try and install the cable with plenty of strain relief!

Ian Coverdale Members Profile Send Private Message Find Members Posts Add to Buddy List Captain Joined: 19 June 2019 Location: Travelling Status: Offline Points: 311	Post Options Post Reply Quote Ian Coverdale Report Post Thanks(0) Quote Reply Posted: 10 September 2025 at 14:16
	Running N2K network to the masthead is a seriously silly design ... I have it too. Makes all instruments connected to N2K network vulnerable to damage from nearby electrostatic discharge (lightning). Later designs use separate serial cable to the masthead with a serial/N2K adaptor at the base which gives better electrostatic immunity ... not 100% mind, any direct hit will blow everything anyway. Changed the bearings in our 12-year old 508/608 wind sensor twice now. When the thing finally dies, we'll take a look at some of the ultrasonic wind sensor options. Used these in my professional world and they really are fit-and-forget.
	Ian & Andrea SV Gabrielle (H445) Liveaboards - currently Montenegro. www.facebook.com/sailinggabrielle

SimonGH Members Profile Send Private Message Find Members Posts Add to Buddy List Commander Joined: 08 September 2021 Location: CT Status: Offline Points: 124	Post Options Post Reply Quote SimonGH Report Post Thanks(0) Quote Reply Posted: 11 September 2025 at 00:07
	yeah, I am intrigued by the ultrasonic sensors myself. I read somewhere that the B&G adapter is NMEA0183 / RS485 -> N2k, but who knows? I like the look of these guys: https://calypsoinstruments.com/shop/ultra-low-power-ultrasonic-wind-meter-ulp-standard-6?category=2&product=product.template%286%2C%29#attr=76,160,65 But their "N2K" version has very little info, and running the N2K up to the mast head is what i want to avoid. It would be so nice if I could use the WS310 serial cable and converter (both of which I already have) with the right protocol version of this... I have a WS310, I have the adapter, and I just ordered the long serial cable. Would be cool to understand if this could work with a small adapter cable or something... if the WS310 is truly NMEA0183 then this would swap in. Need to investigate further... I have a NMEA0183 multiplexer, perhaps i can hook it up that way... Edited by SimonGH - 11 September 2025 at 00:10



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