Shotline Diving Wreck Profile
- Name: Unknown 11
- Type: Dipper dredge
- Year Built:
- Builder: Not known; likely regionally built
- Dimensions: Approximately 72 ft (22 m) long × 28 ft wide
- Registered Tonnage:
- Depth at Wreck Site: 10 m / 33 ft
- Location: Thunder Bay "dumping grounds," Lake Superior
Wreck Location Map
Vessel Type
Dipper dredge (mechanical excavating vessel)
Description
The Unknown 11 dipper dredge is a wooden vessel, approximately 72 feet long and 28 feet wide. It was constructed likely in the 19th or early 20th century, although the exact date remains undetermined.
History
This dredge was part of the 1936 harbor clearance operation in Thunder Bay, where it was intentionally scuttled after being stripped of machinery and superstructure. Its sinking was part of a larger effort to manage derelict vessels in the area.
Significant Incidents
- Intentionally scuttled as part of a harbor clearance operation in 1936.
Final Disposition
The vessel remains largely intact, submerged in the Thunder Bay dumping grounds, with its hull preserved but stripped of machinery. It serves as a significant artifact of industrial maritime heritage.
Current Condition & Accessibility
The wreck is in cold, low-silt conditions, which may help preserve submerged timbers and structural members. The hull is largely intact, exhibiting distinctive features such as a flat barge-like hull and foundations for cranes or booms.
Resources & Links
[shotline_reference_links slug=”unknown-11-dipper-dredge” title=”References & Links”]
The Unknown 11 dipper dredge offers a unique opportunity for researchers to study the evolution of dredging technology and harbor development on Lake Superior, highlighting the importance of documenting such industrial artifacts.
Legacy Notes & Full Historical Record
This section preserves the original unedited Shotline content for this wreck so that no historical detail is lost as we transition to the new logbook format.
Site Identification
- Vessel Type: Dipper dredge (mechanical excavating vessel)
- Derelict ID: #11 in the Thunder Bay Ship Graveyard records
- Construction Date: Not determined (n.d.)
- Material: Wood
- Dimensions: Approximately 72 ft long × 28 ft wide
- Origin: Not known; likely regionally built 19th or early 20th century
Wreck Site & Context
- Location: Thunder Bay “dumping grounds,” Lake Superior (part of the 1936 harbor clearance operation)
- Sinking Mode: Intentionally scuttled—derelict intentionally submerged after stripping
- Depth: Estimated 10–18 m (33–60 ft), consistent with lakebed in the graveyard area
Archaeological Condition
- Hull largely intact but denuded of machinery and superstructure
- Likely exhibits distinctive features: flat barge-like hull, crane or boom foundations, absence of deckhouse, and heavy framing designed to support dredging equipment
- Cold, low-silt conditions may preserve submerged timbers and structural members
Research Value & Next Steps
| Focus | Recommended Actions |
|---|---|
| Construction Analysis | Document hull structure—especially framing and hold reinforcement—to determine dredge load capacity |
| Feature Identification | Look for mounting sockets or wear patterns indicating positions of dipper cranes or winch equipment |
| Timber Study | Extract wood samples for dendrochronological dating and identification of timber species and origin |
| Archival Cross-reference | Review Thunder Bay and Port Arthur harbor logs (pre-1936) for dredge vessel names/dimensions that match hull data |
| 3D Photogrammetry | Conduct underwater photogrammetry to preserve structural details and create a baseline for monitoring |
Historical & Archaeological Significance
The Unknown 11 dipper dredge represents an uncommon artifact of industrial maritime heritage—working vessels adapted for harbor excavation. Its presence in a scuttling graveyard reflects a pragmatic mid-20th-century harbor clean-up, yet offers modern researchers a rare opportunity to study large wooden working craft. Detailed documentation would enrich understanding of dredging technology and harbor evolution on Lake Superior.
unknown-11-dipper-dredge 1936-07-20 23:13:00