Navy ship and submarine encounters are reports of unidentified objects or signals observed from warships, naval aircraft, or undersea platforms. Maritime operations can combine visual witnesses with radar, infrared, sonar, electronic-support measures, and ship logs. That potential makes naval cases important, but public accounts often expose only a small part of the sensor picture because platform capabilities and operational records are classified.

The 2004 Nimitz carrier-group episode is the best-known modern example. Aviators including David Fravor described an unusual object after radar operators reported tracks near the training area; the Defense Department later released an associated Navy video. The case connects military pilot encounters with shipboard detection, although the public evidence does not reproduce every claimed track or establish the object’s origin.

Claims involving objects entering or leaving water are often grouped with USOs and transmedium. A report of apparent water entry does not by itself prove controlled travel through two media. Horizon geometry, sensor mode, loss of track, waves, birds, balloons, aircraft, and distant surface objects can complicate interpretation. Undersea claims face an additional evidentiary barrier because sonar data are rarely public and acoustic contacts can arise from vessels, marine life, geology, or system behavior.

A strong naval case would align calibrated sensor records, deck or cockpit observations, precise platform positions, environmental data, and a documented analytical chain. FOIA releases such as the Brennan McKernan file can illuminate correspondence and administrative handling without necessarily containing decisive case evidence. The role of the U.S. Navy is therefore both operational and archival: its reporting practices determine which incidents can later be assessed while protecting legitimate defense sensitivities.