USS H-1 (Seawolf)
Submarine · United States · Lost 1920 · Baja California & the Mexican Pacific
A World War I–era U.S. Navy submarine that grounded off Baja California in 1920 and now rests, largely intact, in Magdalena Bay.
The Vessel and Her Loss
The USS H-1, an early American submarine that had patrolled the Atlantic coast during the First World War, ran aground in a storm off Isla Santa Margarita in March 1920 while transiting to the East Coast. Salvage efforts by U.S. Army vessels failed to refloat her, and she was struck from the Navy list weeks later. The wreck went unfound for decades until Mexican archaeologists formally documented it in the 2010s.
Vessel
- 1909
- SS-28
- Union Iron Works
- San Francisco, California
- Steel
- Not established
- Not established
- Not established
- Diesel-electric, single screw
- United States Navy
Loss
- March 12, 1920
- Grounding
- Off Round Point, Isla Santa Margarita, Magdalena Bay, Baja California Sur
- Pacific Ocean
- East Coast of the United States, via the Panama Canal
- Not established
- Not established
- Casualty details from the grounding are not established in the sources reviewed.
- Not established
The Wreck Today
- Not established
- Reported largely intact on the seabed near shore
- Not established
- 2016 (formally registered by INAH after fishermen reported the wreck)
- Registered archaeological site under INAH
Position
- 24.45° N 111.98° W
- Approximate position
- Isla Santa Margarita, Magdalena Bay
Approximated to Round Point, the reported grounding location on the western beach of Isla Santa Margarita.
Evidence
Overall confidence: Partially documented (65/100)
Full details of the grounding, casualties if any, and the wreck's present condition beyond photogrammetric survey are not established in the sources reviewed.
El Universal, "INAH archeologists discover WWI submarine in Mexican coasts"
Vessel identity, build year, grounding date and circumstances, and INAH documentation.
