Shipwreck Report: Unidentified Thumb Wreck
Identification & Site Information
- Name(s): Unidentified Thumb Wreck
- Registry: Not documented
- Vessel Type: Propeller
- Year Built: Not documented
- Year Sank: Not documented
- Hull Material: Wood
- Engines: Single Expansion Steam Engine
- Dimensions
- Length: Approx. 160 ft (48.77 m)
- Width: Approx. 23 ft (7.01 m)
- Depth: Not documented
Vessel History
The identity of the Unidentified Thumb Wreck remains a mystery, though its design and features suggest it was a wooden propeller-driven Steamship from the mid-19th century. Propeller steamers like this vessel were commonly used on the Great Lakes for transporting cargo and passengers. Based on the intact features and machinery, this wreck likely served as a cargo carrier.
The presence of a haystack boiler and a single-expansion steam engine identical to those on the propeller Indiana (whose machinery was studied by the Smithsonian) suggests this vessel may have been built in a similar era, likely between the 1840s and 1870s. The lack of a propeller and the condition of the wreck indicate it may have been salvaged or suffered mechanical failure before sinking.
Wreck Site Information
- Lake: Lake Huron
- State/Province: Michigan
- Depth: Not documented
- GPS Coordinates: Undisclosed
Site Description:
The wreck lies relatively intact on the lakebed, with notable features and artifacts present:
• The main Deck and Hull are intact, but the fantail (Stern overhang) is broken.
• Disarticulated aft Deck hangs off the Stern, with propeller shaft hanger bearing rods visible.
• Machinery:
• Boiler: Haystack-style boiler with a feedwater pre-heater.
• Engine: Single-expansion steam engine, similar to the propeller Indiana’s machinery.
• Cargo Winches: Two cargo winches with frames are located on the port side near the engine.
• Artifacts:
• Anchor Windlass: Features an elevated rocker arm, likely operated from the Forecastle or spar Deck.
• Anchors: Sitting on the Deck near the bow.
• Mast: Remnants of a mast are visible.
• Capstan and Bit: Located near the Stern.
• Hand Carts: Several scattered around the site, indicating its cargo-handling function.
• Structural Features:
• Sides of the ship remain extant, lying next to the Hull on the bottom.
• Evidence of overhanging sponsons near the Stern.
Diving Notes & Advisories
• Depth Consideration:
The depth of the site is not documented but is presumed to be accessible to recreational or technical divers depending on its location.
• Visibility:
Visibility in Lake Huron is typically good but can vary based on weather and sediment conditions.
• Preservation Status:
The site is protected as part of Michigan’s underwater heritage. Divers are encouraged to observe respectfully and refrain from disturbing artifacts or structural components.
Site Significance
The Unidentified Thumb Wreck offers valuable insights into mid-19th-century Great Lakes shipping and Steamship design. The intact Hull and presence of machinery, including the haystack boiler and single-expansion engine, make it a critical site for understanding the technological advancements of the era. Its similarities to the Indiana suggest the vessel was built during a pivotal period in Great Lakes maritime history, transitioning from sail to steam.
The presence of hand carts and cargo winches indicates its use in freight transport, while features like the anchors and Capstan highlight its operational capabilities. Identifying the wreck could provide a missing link in the narrative of Great Lakes shipping development.
Keywords:
Unidentified Thumb Wreck, Lake Huron shipwrecks, wooden propeller vessels, 19th-century steamships, Great Lakes maritime history, haystack boiler, advanced diving sites.