Welcome to 1847!
From the Gazette and Times.
THE PROJECT OF THE LONG ISLAND CANAL--of which we have once or twice already made brief mention--seems to find great favor, notwithstanding the opposition of the Brooklyn Eagle. The proposed line of navigation commences at Gravesend Bay, thence through the neck separating Coney Island from the main land, and so on to Peconic, and when completed will enable vessels to navigate the bays from Coney Island to South Hampton--a distance of 80 miles--with 4 feet water at low tide.
--Brooklyn Daily Eagle, Tuesday, January 26, 1847
I'm not seeing much reference to this canal later; it sounds like it would have made Coney MORE of an island. (At this point there was likely a bridge over Coney Island Creek to bring people to Coney from the mainland. Now, of course, it's not an "island" at all, with much of the creek filled in.)
I can't get Rochester History's page to load but the cached version says a company WAS incorporated in 1848 to build a Long Island canal, and that "no results were achieved by either company toward carrying out the purposes for which they were incorporated."
The page implies the Shinnecock Canal in Long Island--a much more logical place for a canal than an 80-mile canal from Coney Island to South Hampton, IMO--opened in 1892. Wikipedia cites that date too.
There was more talk of a different canal exactly one month later:
QUEENS CO. CANAL.--Application will be made to the legislature of this state at its present session, to incorporate a company to be called the "Jamaica and New York canal company," for the purpose of digging a canal from Beaver pond in the village of Jamaica to Jamaica bay, and also to have power to open and straighten the ditches from Jamaica bay to Coney Island bay.
--Brooklyn Daily Eagle, Friday, February 26, 1847
Again, the only page I can find on this is from history.rochester.edu, which, at time of writing, wouldn't load! The cached page seems to imply nothing was done on this either.
I wonder if the lack of progress on canals came with the increasing importance of railroads, or if everyone just couldn't get their act together? Maybe both.