Updated 2021-04-15 !
This assumes that You have Homebridge up and running on a Raspberry Pi
Check this post !! "ANY" temp source can be HomeKit enabled.
I have searched for a solution transmitting the NMEA data, from the
navigation network, via WiFi, to for example iSailor or other Tablet/Phone applications.
Most of these applications just accepts NMEA0183(N1) but many boats are also using SeaTalk 1(ST1) and NMEA2000(N2K).
This post will cover, kept compact, my best findings covering both a DIY
and a commercial approach to handle the different protocols.