NBM Dive Site Resource
U-550
Nantucket offshore, Massachusetts offshore, United States
A Type IXC/40 lost after attacking Pan Pennsylvania and rediscovered south of Nantucket in 2012. A documented deep discovery and diving site requiring specialist technical expedition support. Published depths differ; this profile does not promise routine charter access.
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Featured Hero Photograph
Aquatic life at this dive site
What divers may encounter
Three reviewed connections are featured here. Sightings vary by season, conditions, and chance, so they are never guaranteed.
Aquatic life research in progress
NBM is reviewing a likely local species for this position.
Aquatic life research in progress
NBM is reviewing a likely local species for this position.
Aquatic life research in progress
NBM is reviewing a likely local species for this position.
Site media
Photographs
Three views rotate from the published gallery on each visit.
Contributor media
Dive videos
Three featured video positions are reserved on every profile.Regional location and nearby land
Location map
Regional overview includes nearby land for orientation. It does not establish a navigation waypoint or an entry location.Map data © OpenStreetMap contributors
Recent field observations
Diver-reported temperatures
Automatically checked observations from dives during the past 14 days. Three reports are visible at a time; scroll for more.A report that passes the automatic checks will appear here with the dive date, diver’s display name, and temperatures at each depth.
Reports are automatically checked for plausible dates, depths, and temperatures. They are observations, not forecasts; confirm conditions before diving.
Why divers know this place
Highlights
The submarine wreck is connected with the 1944 Pan Pennsylvania convoy action and the 2012 diver discovery.
Shipwreck-only module
The wreck
This section appears only on shipwreck records and brings the vessel, its loss, present condition, access, and responsible wreck-diving considerations into one place.
- Vessel type
- German Type IXC/40 submarine
- Year built
- 1943 (launched)
- Year sunk
- 1944
- Cause of loss
- Sunk on 16 April 1944 after depth-charge and gunfire attacks by U.S. destroyer escorts.
- Present condition
- The submarine wreck is connected with the 1944 Pan Pennsylvania convoy action and the 2012 diver discovery.
- Penetration guidance
- External wreck context only. This record does not authorize penetration or artifact recovery.
Before you arrive
Access notes
A documented deep discovery and diving site requiring specialist technical expedition support. Published depths differ; this profile does not promise routine charter access. Confirm current access, restrictions, weather, tidal windows and support before planning a visit.
Plan within your training
Conditions and hazards
Depth, decompression exposure, currents, sea conditions, fishing gear, damaged metal and fragile wreck structure. Respect any human remains and do not disturb objects.
Independent resource notice
This record is a starting point for independent verification. Access, closures, moorings, weather, currents, depth, visibility, operator availability, and site conditions can change without notice. Confirm current information with the responsible operator, property owner, managing authority, or another qualified local source before planning or attempting a dive.