NBM Dive Site Resource
SS Henry Chisholm
Isle Royale, Michigan, United States
TECHNICAL DIVE REQUIRED FOR THE DEEPER SECTIONS — SS Henry Chisholm shares the Rock of Ages reef site with Cumberland and reaches approximately 155 ft / 47 m. The deepest engine, shaft and wreckage areas exceed recreational limits.
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Historic 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.Published reference location
Location map
The marker shows the public coordinates associated with this profile. Confirm current access, moorings, and departure details before the dive.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.
Seasonal planning reference
Typical monthly conditions
Long-term averages, not a forecast. Actual air and water conditions can change quickly and may vary across the site.Moderate-confidence match — Matched by documented Great Lakes port/area. Air and surface-water values are regional planning averages. No bottom-water line is published because a comparable depth-specific record has not yet been verified.
| Month | Average air | Surface water | Bottom water | Bottom measurement depth |
|---|---|---|---|---|
| Jan | 11.2°F / -11.6°C | 36.3°F / 2.4°C | No reliable record | — |
| Feb | 15.4°F / -9.2°C | 33.2°F / 0.7°C | No reliable record | — |
| Mar | 27.0°F / -2.8°C | 38.5°F / 3.6°C | No reliable record | — |
| Apr | 39.5°F / 4.2°C | 36.6°F / 2.6°C | No reliable record | — |
| May | 52.0°F / 11.1°C | 36.1°F / 2.3°C | No reliable record | — |
| Jun | 61.2°F / 16.2°C | 39.2°F / 4.0°C | No reliable record | — |
| Jul | 67.0°F / 19.4°C | 43.6°F / 6.4°C | No reliable record | — |
| Aug | 65.5°F / 18.6°C | 55.9°F / 13.3°C | No reliable record | — |
| Sep | 57.2°F / 14.0°C | 54.9°F / 12.7°C | No reliable record | — |
| Oct | 44.1°F / 6.7°C | 48.3°F / 9.1°C | No reliable record | — |
| Nov | 29.8°F / -1.2°C | 42.3°F / 5.7°C | No reliable record | — |
| Dec | 17.1°F / -8.3°C | 39.6°F / 4.2°C | No reliable record | — |
NOAA NCEI 1991–2020 U.S. Climate Normals — Duluth, MN
1991–2020 climate normalsReview source ↗NOAA NCEI Coastal Water Temperature Guide — Mid Superior
Historical monthly station averagesReview source ↗Bottom temperature is never inferred from surface temperature. A blank month means no reliable depth-specific average is available. Data reviewed 2026-08-26.
Why divers know this place
Highlights
Large intact steam engine, drive shaft and propeller among scattered wooden hull remains at the Cumberland/Chisholm site.
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
- Wooden bulk freighter
- Cause of loss
- Grounded on Rock of Ages reef
- Wreck orientation
- Scattered hull remains with intact machinery
- Present condition
- Engine, shaft and propeller dominate the site
- Protection or memorial status
- Isle Royale National Park
History and significance
The wooden hull remains overlap the earlier Cumberland site.
Plan the trip
Dive boats that visit this wreck
Superior Trips publishes this wreck in its Isle Royale inventory and describes Heyboy liveaboard trips that dive the island's major wrecks. Actual selection depends on weather, park rules, diver qualifications and trip profile.
Open boat profile →Grand Portage, MinnesotaDiscovery — Isle Royale and North Shore LiveaboardIsle Royale ChartersIsle Royale Charters explicitly publishes this wreck as a possible Discovery liveaboard destination; actual selection depends on weather, permits, diver qualifications and trip type.
Open boat profile →Regional context
Located within
Before you arrive
Access notes
Plan the dive for the intended portion of the combined Cumberland/Chisholm site. NPS notes a buoy attachment at the engine around 125 ft, while wreckage continues deeper. Isle Royale dive registration and current park requirements apply. Published coordinates support regional discovery and are not a substitute for current navigation, active mooring information, operator guidance, permits, weather, or a dive plan.
Plan within your training
Conditions and hazards
Depth variation, decompression risk in deeper sections, cold water, darkness, remote emergency response, entanglement, silt and mixed wreckage from two vessels. Penetration requires separate wreck training.
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.