My AIS-800 is hiding from me!

Richard Granshaw · Posted: Wed Jul 02, 2025 12:11 am Post subject: My AIS-800 is hiding from me!

I bought a 2020 C-Dory TomCat this spring and I've been learning the mechanical and electronic systems. I've successfully registered the Garmin devices and updated the software, but I am stuck trying to locate the AIS-800 device. It shows up on the chart plotter and appears to work fine, but I would like to change the name of the boat in the AIS data as it is still labeled TOM CAT. It's probably been that way from new.

To change the name, I need physical access to the device to attach a USB cable. Unlike all the other devices, I can't find it. I know it should be located away from metal, wiring and cables, and I'm wondering if it is above the ceiling liner.

Does anyone know where these are normally located? I'm assuming it may have been installed during manufacture, and above the ceiling liner seems like a good place to put it - until one wants to update the data or replace the unit.

Thanks everyone!

Richard

srbaum · Posted: Wed Jul 02, 2025 6:31 am Post subject:

Richard, I’ve got one in my 26 and one in my trimaran. The AIS is relatively small, so it could be almost anywhere. It is connected to an AIS antenna or to a splitter between your VHF radio antenna and your VHF. I would simply follow your antenna and the wire back to the radio.

colbysmith · Posted: Wed Jul 02, 2025 11:00 am Post subject:

Quick question. I'm assuming you purchased the boat used and the MMSI registration was created by the previous owner. Have they transferred that number to you? The AIS-800 is a small box that I think would be mounted near easy access to the antenna and NMEA system. Since it has some indicator lights on it,I would also think it would be somewhere that the indicator lights could be seen. Colby

KevinMc · Posted: Wed Jul 02, 2025 2:18 pm Post subject: Tom Cat

1Ensure that the MMSI number is entered into the VHF radio correctly as it can only be entered once. If the MMSI number is entered incorrectly, the VHF radio will need to be sent into Garmin to have the incorrect MMSI number cleared. Contact Product Support to have an RMA (Return Materials Authorization) issued prior to sending in the device. This will ensure the fastest service in resolving the issue.
The AIS 800, is a splitter in the antenna cable allowing the radio to communicate with the GPS and transmit location. Newer or more expensive radios have their own GPS built in.I don't know if it is possible to reconfigure the AIS 800.When I bought my used boat I upgraded my radio and got a new MMSI number with new boat decription.

thataway · Posted: Wed Jul 02, 2025 5:36 pm Post subject:

It is unlikely to have been installed at the factory. The vast majority of times, all electronics are installed by the local dealer or electronic shop. There will be one NMEA 2000, at least one or two antennas, a GPS antenna, attatched to the unit. You don't need ot change the specifications, but as Colby noted the MMSI number, which changes emergency notification data, as well as ownership. That may be a "factory" reset--ie back to Garmin for reset. There is a USB macro port on the right side of the part of the unit which recieves the Power supply and the NMEA 2000 cable.

ssobol · Posted: Wed Jul 02, 2025 6:31 pm Post subject:

thataway · Posted: Wed Jul 02, 2025 10:49 pm Post subject:

On the A800 AIS:

colbysmith · Posted: Wed Jul 02, 2025 11:45 pm Post subject:

Richard Granshaw · Posted: Thu Jul 03, 2025 2:49 am Post subject: My AIS-800 is hiding from me!

Thanks for all the useful tips and information, especially from colby and thataway!

Colby, the previous owner had not transferred the MMSI to me. I think the dealer handled that for her when she bought it, so she wasn't aware of how to do it.

I did a search and found I could manage an existing MMSI registration at https://www.boatus.com/MMSI/ if the original registration had been entered there. Fortunately, the MMSI number for my TomCat was there. One of the options allows transfers, and I was able to transfer the MMSI to a new owner, that being myself.

Then I filled in my contact info, state registration, etc. for the TomCat. Some of the fields are for much larger vessels and I left those.

I was able to specify a new name, C-CAT, and the form asks for the old name, if known. The old name is TOM CAT, so I put that in.

This does at least update some public data, but I don't yet know how that gets used and distributed, or how much verification there is.

Working on thataway's information that the electronics get installed by the dealer, I'm in the process of contacting the original dealer for the boat.

On the aft roof of the cabin, there is a GARMIN GPS 24xd Receiver and Antenna device. That's in a good location for accurate GPS readings, and maybe the AIS-800 doesn't need to be in a carefully-selected location as a result. It can use the GPS numbers from the 24xd. Following the cables from the antennas leads to the area behind and below the main helm in the cabin. The cables become difficult to follow, so it's probably time to cut some of the zip ties to make the job easier.