The M/V Capetan Yiannis, a freighter, was damaged and put out of service in an accident in the Port of Milwaukee. P brought suit against the charterer (i.e., lessee) of the ship, Afram Lines (D), and also against the City of Milwaukee (D), which owns the port, and the city's insurer (D), seeking damages for the damage to the ship and the loss of revenues from the ship's being out of service because of the accident. P designated the suit as one in admiralty. City (D) counterclaimed for the damage that the accident had caused to the slip in which the ship was berthed at the time of the accident. The district judge granted the city's (D) motion for summary judgment and dismissed P's claims against it. P appealed.