[DG] [DG11] Electric storms killing SeaTalkNG ports

[Ulf]

Hi everyone,
Since I bought my boat some 2½ years ago I've been replacing instruments at a steady pace, always because of the same issue: An electric storm nearby kills the SeaTalkNG ports - the instrument itself continues to work fine, just can't communicate on the SeaTalk network anymore.

The following instruments have had the SeaTalk ports die, not all at once but one now and then:
AIS-650
i60 wind display
i50 tridata
P70S autopilot control head (twice)

It's a 40 foot center cockpit fiberglass sailboat, mostly sailing winter/spring in the Caribbean. The SeaTalk ports died while the instruments were switched off and all but the AIS were/are installed at the helm, so naturally I suspect there's something making the helm position more exposed, but if so, I can't quite figure out what. Also, I could just have had a bunch of bad luck, but by now that theory doesn't seem very likely anymore :)

My setup is 100% Raymarine (yeah, I'm a fan despite a network port blowing up every 3-4 months):

- eS78 MFD (downstairs at navigation table)
- Quantum 1 radar (cable connected to eS78 MFD)
- AIS650 (antenna next to radar on aft of boat - 3 feet distance)
- Ray218 VHF (antenna on masthead)
- Autohelm 300 autopilot (mounted aft, close to hydraulic motor)
- ST7000 autopilot control head (downstairs at navigation table)

At the helm:
- i50 TriData
- i60 Wind instrument (masthead transducer)
- P70S autopilot control head

Everything is SeaTalk networked, the Autohelm 300 and ST7000 through an E22158 SeaTalk 1/NG converter kit and the Quantum radar to the eS78 MFD through a SeaTalk HS cable.

My current working theory is, that the i60 wind transducer at the masthead, and/or the wind transducer cable in the mast picks up an EMP from a nearby lightning, releasing it as an induced over-voltage in the SeaTalk NG network cable - they run 25 feet next to each other in the cable duct to the helm station - and thus killing whatever SeaTalk port is the weakest/unluckiest picking up the surge. (I know, the aluminum mast should act as a Faraday cage for the transducer cable and the cable shield is grounded, but still my best guess...)

So, I'm planning to replace the i60 Wind and i50 TriData at the helm with an i70 multifunction instrument and have the wind/log/depth transducer cables terminate an iTC-5 Transducer Converter at the foot of the mast instead of going to the helm.

But, this is just a theory - any thoughts, ideas or similar experiences are very welcome!

[Derek - Raymarine - Moderator]

Hi Ulf,

Thank you for your enquiry.

This is an unusual scenario and yes - bad luck just does not explain it!

The first issue regarding EMP or local static discharge - this can be very difficult to resolve and this FAQ here will help with ideas to track down the possible causes.

The key to improving protection is to take care with grounding and how equipment, deck fittings, hull fittings and masts are grounded, similarly there needs to be a dedicated RF ground installed and care when grounding the battery negative needs to be taken to ensure this is not compromised during connection to equipment.

It would also be a good idea to check the vhf antenna and AIS antenna to make sure there is no possible leakage for RFI there and we suggest also connecting the AIS through NME0183 and the vhf through NME0183 since this will interpose an opto isolator into the system between the antenna and the equipment and will add an additional layer of resilience to the system onboard.

Regards

Derek

[Ulf]

Hi Derek,
Thank you for the link to the electrostatic FAQ - I didn't find that myself. And I really like the idea with NME0183 converters between the radios and the rest of the network for all the reasons you gave!

Thank you,
:) Ulf

[Derek - Raymarine - Moderator]

Hi Ulf,

You're welcome!
Regards

Derek