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Phantom reef incident off San Francisco

1947-11-24·approximately 400 miles west of San Francisco, Pacific Ocean·USN·unresolved

On November 24, 1947, the Navy sent the survey ship MAURY to investigate reports of a huge object in the water about 400 miles west of San Francisco. The ship detected an echo 1600 yards away that vanished when they approached to within 400 yards.

“THE PHAN'IOM REEF - On November 24, 1947, the Navy denied that it had found a phantom reef or other obstruction to navigation at a point about 4oO miles west of San Francisco. TM Navay Survey ship MAURY, s ent out there in r esponse to reports of ships that some hugh object had been seen in the water in that neighbo rhood , reported that when in the approximate 1 titude and long:1.tu:ie of the supposed obstruction they picked up an echo from soll8t hing in the wa+.er 16oo yards f rom the ship; but that Tfhen they had steamed to within 4oo yards of thi s, the echo vanished.”

Verbatim from DOW-UAP-D088.pdf · View original on war.gov

Case details

Date
1947-11-24
Date exactness
Known to the day
Location
approximately 400 miles west of San Francisco, Pacific Ocean
Country
United States
Branch
USN
Unit
MAURY (survey ship)
Sensors
radar
Size
Huge object

Resolution

Radar echo detected at 1600 yards vanished when ship approached to 400 yards; no phantom reef found

Source document

Agency: DoW

File: DOW-UAP-D088.pdf

Case ID: 1947-USN-2B1C80

View original on war.gov →

Quote checked against the original file.

This sighting

approximately 400 miles west of San Francisco, Pacific Ocean / 1947

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