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Explore the Monohansett Wreck in Thunder Bay National Marine Sanctuary

In late 1907, the wooden bulk freighter Monohansett sought refuge from Lake Huron’s nasty November weather in the lee of Thunder Bay Island. The crew and vessel were protected from the storm, but not from an engine room fire that quickly spread through the cargo vessel’s old wooden timbers. The Monohansett burned to the waterline and today is one of the most popular sites in the sanctuary. Readily accessible by kayakers, snorkelers, and divers of all abilities, a visit to the Monohansett often provides sanctuary users with their first shipwreck experience.

Wreck History

With 900 tons of coal onboard, the 165-foot Monohansett burned within minutes. The crew of 12 was rescued quickly, likely due to the disaster’s proximity to Thunder Bay Island’s life saving station. The frequency of shipwrecks in the vicinity of Thunder Bay led to the establishment of U.S. Life-Saving Service Stations at Thunder Bay Island in 1876, and at nearby Middle Island in the 1880s. Crews that trained extensively in the use of rescue boats and other lifesaving equipment manned these remote facilities, and they were among the busiest stations on Lake Huron.

For 35 years, the Monohansett thrived off the shipping demands of growing Great Lakes industries. The single-screw steamer hauled bulk cargoes of raw materials, particularly iron ore from Michigan’s Upper Peninsula. The construction of the Monohansett, with the boiler and engine machinery aft, and the technological advancement from sidewheelers to screw propellers, reflects Great Lakes’ freighters answer to demands for more and more cargo space. Even the heavy framing structure of the vessel, with oak keelsons on top of evenly spaced frames, accommodates heavy bulk cargoes of iron ore, coal, and lumber.

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Diving and Snorkeling the Wreck

Just 500 feet west of Thunder Bay lighthouse, and in only 18 feet of water, the Monohansett is exposed to immutable forces of waves and ice. The bow is missing and the remaining wreckage is broken into three large pieces. The 4-foot diameter boiler reaches to within ten feet of the water’s surface with the openings to its steel drums exposed and the once-powerful steel propeller sits upright on the limestone lake bottom.

The Monohansett is one of approximately twenty-five sanctuary shipwrecks with a seasonal mooring buoy. To provide better access to Thunder Bay’s historic shipwrecks, the sanctuary maintains seasonal moorings at many popular shipwreck sites. The moorings make the sites easier to locate and provide a safe means of ascent and descent for divers. The moorings also eliminate anchor damage to these unique and irreplaceable historic sites.

Thunder Bay's shipwrecks are magnificent, yet vulnerable. Natural processes and human impacts threaten the long-term sustainability of our underwater maritime heritage. Through research, education, and community involvement, the sanctuary works to protect the Monohansett for future generations. Protecting Thunder Bay's underwater treasures is a responsibility shared by the sanctuary, its many partners, and the public.

With thanks to NOAA and the team at Thunder Bay National Marine Sanctuary.

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monohansett noaa marine

Monohansett 3D Wreck Tour

The 2D and 3D visualisations are intended as a guide only and does not pretent to be entirely accurate. Always research/plan your dive with care and always dive within your limits. You are not authorised to reproduce/publish any content from this website online or in print without permission. Copyright - Mike Postons/3DeepMedia.

2d shipwreck

2D Map

Monohansett Wreck Specs

Max Depth: 5.4m (18 feet)

Location: Thunder Bay - Lake Huron

Length: 49 metres (160 feet)

Description: In late 1907 the Monohansett burned to the waterline after an engine fire. Today it is one of the most popular sites in the sanctuary. Readily accessible by kayakers, snorklers, and divers of all abilities, a visit to the monohansett often provides sanctuary for users on their first shipwreck experience

Image Gallery

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Monohansett Wreck Video

Monohansett Project Credits

3deep - 3D Shipwreck Mapping, Thunder Bay National Marine Sanctuary

Other Thunder Bay 3D Wrecks

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