Mary M – Lake Michigan Steamer Shipwreck (1918)

Shotline Diving Wreck Profile

• Name: Mary M
• Type: Wooden-hulled passenger steamer
• Year Built: 1909
• Builder:
• Dimensions: Length X ft (Y m); Beam; Depth of hold
• Registered Tonnage:
• Location: Chicago harbor, near breakwater

Wreck Location Map

Vessel Type

Wooden Passenger Steamer

Description

A small wooden passenger vessel designed to ferry passengers—likely across Lake Michigan or between Chicago and Michigan ports. Specific dimensions and engineering details are not currently documented in accessible sources.

History

Operated in or near Chicago harbor, carrying passengers and a small crew. On her final voyage, she had 138 passengers plus 8 crew members aboard, all of whom reached shore safely after the wreck.

Significant Incidents

• Date & Location: Evening of July 28, 1918 — struck the Chicago harbor breakwater
• Cause: Navigational collision—likely miscalculation or reduced visibility
• Casualties: None—all 146 persons on board (138 passengers and 8 crew) survived, making their way to shore safely

Final Disposition

• The vessel sank off the city, at or near the breakwater.
• No known salvage, official Notices to Mariners, or subsequent site surveys.
• Given her wooden construction and urban harbor location, it’s likely she was salvaged or cleared soon after sinking.

Current Condition & Accessibility

The wreck site is likely disturbed due to urban harbor activities, and no recent surveys have been documented.

Resources & Links

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The sinking of Mary M in 1918 reflects a fortunate outcome: despite striking the Chicago harbor breakwater, all passengers and crew survived. Though she sank near a major port, details on her construction and subsequent salvage remain sparse. This vessel’s story offers insight into civilian maritime operations on Lake Michigan during WWI-era urban conditions.