Mark Harmon, who plays Gibbs, had his sign language tested by Abby. In the early 1990's Harmon appeared in a drama series called Reasonable Doubts (1991), in which he was assigned to work with the deaf female lead because his character was one of the few police officers who could speak in sign language.
Kate states that the boat that came ashore, without a captain, was called The Mary Celeste. The fact that there is no one on board, mirrors the historical facts of the real Mary Celeste which was found adrift in 1872 deserted. The Mystery of the Mary Celeste has never been solved.
Ducky's comment about Sgt. Linn learned his crime investigative techniques watching "Kojak" reruns is a bit of an in-joke, since NCIS co-creator Donald P. Bellisario actually wrote an episode of Kojak (1973) early in his career.
Elena Lyons plays reporter Diane Fontaine in this episode; she played Lauren Fontaine on USA High (1997) in the late 90s.