Mayor Bill de Blasio captured New Yorkers' imaginations last month with his proposal to create a citywide ferry network. But look at a map of the routes and one thing jumps out: The entire West Side of Manhattan is blank.

Yes, existing ferry lines connect to Brookfield Place and Pier 79 at West 39th Street. But points farther north along the Hudson River are unserved and would remain so under the mayor's plan.