I've always used "Fry" rather than "Ferry".
As for what precedes "Fry", a mixed bag in my systems:
-- if a ferry route is normally served by only one vessel, use the vessel name, such as "GeoBlaFry" in the Yukon for the ferry crossing the Yukon River at Dawson
-- if a ferry route crosses a river, use the river name (in the Northwest Territories, it's used by ferry routes replaced by ice bridges in the winter, but it has less to do with that than with Tim's preference -- if it had been up to me, I could've gone with vessel name)
-- in British Columbia, the ferries connecting the island segments of the Trans-Canada Highway to the mainland go by the
destination terminal:
in Nanaimo on Vancouver Island, it's Hor(seshoe)BayFry
in Horseshoe Bay on the mainland it's Nan(aimo)Fry
in Skidegate on Haide Gwaii it's Pri(nce)Rup(ert)Fry
in Prince Rupert on the mainland it's Ski(degate)Fry.
-- not necessarily true elsewhere in BC, for example the ferry terminals on the route connecting two BC 17 segments (and also other routes) use the departure location rather than the destination
-- in Quebec, the ferry route connecting QC 138 segments (served by two vessels, for faster service) go by the departure terminal; this is how mapcat did it, and I haven't changed that
-- in Alaska, the Alaska Marine Highway System ferry terminals (serving multiple destinations with multiple vessels) are all labeled "AMHSFry", to distinguish them from other ferry services like the Rainforest Islands Ferry. which sporadically serves Mitkof Island (Petersburg) and other places with no numbered state highways