Do you want the AIS data on the chartplotter?
Does the plotter or AIS have GPS input?
You can get converters for 183 and 2k........... Edit, looks like this might work- you will possibly need 2, one to get AIS data on your plotter (if it accepts AIS data!) and one to get the GPS data to your VHF. (Depending on your plotter and how the converters work you may get it to share data with the VHF by connecting the VHF to the out of one of the 183 channels on the plotter loom)https://www.quark-elec.com/product/q...ional-gateway/
I have a similar setup but both my plotters are 183 and 2k so I can get round it-
2x garmin plotters, Suzuki outboard, AIS transmitter on 2k.
VHF gets its GPS from the 183 from one of the plotter out channels.
Is it an old poltter you have? If so maybe worth considering getting a 2k and 183 plotter rather than converters as it is money you will never see back.
OR if you can, send the AIS and GPS antenna back and get a 183 AIS transciever with GPS antenna input and plug a normal GPS antenna into AIS (if your chartplotter has GPS input you don't need it on the AIS)
They claim NMEA is a standard system, whilst that is somewhat true it is like USB connectors, the plugs look the same but how the older units and newer units share data is not a certainty to work correctly. As an example my 5 year old garmin plotters do not like a late 2018 AIS transciever on NMEA 2k (there are quite a few revisions of NMEA 2k hence the problem), yes it works but the data isn't 100% correct.....one for another thread if interested later. I'm waiting on garmin confirming what revision of nmea 2k is running before I do anything else..
Would need to know specifics of EXACTLY what kit you have to better advise you but it sounds like you perhaps have a mish mash of kit that isn't ideal but something will be workable with some creativity I'm sure (and money!)