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The destroyer escort USS Eldridge underway at sea
USS Eldridge (DE-173) at sea, around 1944. Later versions of the story name this ship. U.S. Navy · Public domain · source · via Wikimedia Commons
IS IT TRUE?

Was the Philadelphia Experiment real?

Verdict · Legend

No record supports it. The story traces to letters sent to a UFO author in 1955 and 1956.

Legend: Comes from myth, literature or tradition, not physical evidence.

The short answer

There is no evidence the Navy made a ship invisible or teleported it in 1943. The story starts with letters from a man calling himself Carlos Allende, the newspaper report he cited has never been found, and the ship named in later versions was somewhere else. The Navy's best guess is that real wartime work, especially degaussing, got garbled into legend.

What the record shows

  1. The story begins after Morris K. Jessup published The Case for the UFO in 1955. A correspondent named Carlos Miguel Allende wrote to him describing a 1943 Navy test in Philadelphia that made a ship invisible and sent it to Norfolk and back. 1
  2. Allende said the event was reported in a Philadelphia newspaper. That newspaper has never been identified. 1
  3. The Office of Naval Research says it has never studied invisibility, in 1943 or at any other time. ONR was not founded until 1946. 1
  4. USS Eldridge was not commissioned until August 27, 1943, and stayed in New York until September. In October, the month of the supposed test, it was on its shakedown cruise in the Bahamas. Its 1943 deck log survives on microfilm. 2
  5. In 1999, veterans who served on the Eldridge told a Philadelphia newspaper the ship never made port in Philadelphia. 2
  6. The Navy points to degaussing, which made ships "invisible" to magnetic mines, and to 1950s generator tests on USS Timmerman that produced corona discharges. No crew were harmed in those tests. 1
  7. The letter writer was later identified as Carl M. Allen. He said years later that he wrote notes in Jessup's book "to scare the hell out of Jessup." 2

Where the claim comes from

Everything traces back to Allende's letters and an annotated copy of Jessup's book mailed to ONR in 1956. Two ONR officers took a personal interest and had about 25 typed copies made, which helped the story spread. 12

What would change our verdict

A dated 1943 document, such as an order, log entry, test report or newspaper story, that places a test like this in Philadelphia.

Go deeper in the archive

Roswell: The Crash of 1947Explorer dossierArea 51: The Secret Base in the DesertExplorer dossierOperation PaperclipExplorer dossier

Sources

Checked 2026-11-02.

  1. PRIMARY SOURCE
    “Philadelphia Experiment: ONR Information Sheet.” Naval History and Heritage Command. https://www.history.navy.mil/research/library/online-reading-room/title-list-alphabetically/p/philadelphia-experiment/philadelphia-experiment-onr-info-sheet.html
  2. REFERENCE WORK
    “Philadelphia Experiment.” Wikipedia. https://en.wikipedia.org/wiki/Philadelphia_Experiment

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