Most likely they don't have a VHF marine channel they use.
Many of their COMMS would be mainly via cell phones, as most calls from pleasure boaters came in this way these days.
If anything maybe would start off on channel 16 and switch off to a working channel.
You would have to search during the busy boating season of the VHF marine band. Also it would be good to do this search during the early part of the boating season, since many boats have mechanical issues the first time in the season. Also try late in day or evening with many boats not running after a day spent at anchor.
This time of year they are super slow.