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Map of Monohansett Wreck (Thunder Bay National Marine Sanctuary)
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Boat entry

Monohansett Wreck (Thunder Bay National Marine Sanctuary)

Michigan, United States
Open Water suggested3–6 m depthBoat entry

Boat dive — see Entry & access.

Monohansett Wreck (Thunder Bay National Marine Sanctuary) at a glance

Monohansett Wreck (Thunder Bay National Marine Sanctuary) is a boat dive site in Michigan, United States with depths of 3–5.5 m (10–18 ft). Typically most favorable Jul · from 3 years of archive data. Divers commonly see Crayfish, Smallmouth bass, and Round goby. Check the latest conditions and entry details before you go.

Wind model · graded 14h ago
—

Tap a factor for its source and model point

Site hazards: Surface chop and boat/paddle traffic, sharp wreckage in shallow water, cold water

Read the full hazards ↓

Dive windows this week

Best: Thu
Fri8:00–16:00
Sat10:00–12:00
Sun8:00–20:00
Mon8:00–20:00
Tue15:00–20:00
Wed8:00–20:00
Thu8:00–20:00

Favorable windowModerate window— no window

First light 6:37 · Sunrise 7:07 · Sunset 19:51

Source: Open-Meteo wind · graded 14h ago

Forecast only — always assess conditions on site.

Forecast · NOAA tide model

Tide & slack timing

Loading tide predictions

Recent diver reports

Dated firsthand observations from divers — not current conditions.

No diver reports for this site yet. — one dated observation helps every diver after you.

Dived here today — did the forecast match?

What Divers Say

Known for: Crayfish, Smallmouth bass, Round goby
Best time: June-September on calm days; site is exposed to wind from most directions

Based on community reviews and site data. Conditions vary — always verify before diving.

Best months, historically

What conditions have historically been typical at this site, month by month — not a forecast.

  1. Jan12% 21 kn
  2. Feb11% 22 kn
  3. Mar6% 21 kn
  4. Apr14% 20 kn
  5. May32% 15 kn
  6. Jun31% 16 kn
  7. Jul43% 14 kn
  8. Aug29% 16 kn
  9. Sep40% 15 kn
  10. Oct11% 20 kn
  11. Nov2% 23 kn
  12. Dec9% 22 kn

July hastypically had the largest share of favorable days here. Conditions vary year to year — this is historical context, not a forecast.

Based on 3 years of archive data. Bar height shows the share of days each month whose conditions have historically scored favorably.

Marine life seen at this site

Species noted at this site — not a promise of what you’ll encounter.

Species seen here

Fills & rentals nearby

Facts from OpenStreetMap, corrected by the community — listed by distance only. Details change; confirm with the shop.

Shop facts come from OpenStreetMap and community corrections, shown nearest first. PickADive lists facts and contacts only — no listing is sponsored or ranked.

Data updated July 2026

Site details

The Monohansett was a wooden bulk freighter that caught fire and sank in the lee of Thunder Bay Island in November 1907 while sheltering from a Lake Huron storm. The wreckage lies broken into three large sections in only about 18 ft of clear water roughly 500 ft west of the Thunder Bay Island lighthouse, with the boiler reaching to within 10 ft of the surface and the propeller upright on the limestone bottom. Its shallow depth makes it popular with divers, snorkelers, paddlers and the local glass-bottom boat.

boatwreck

Surface chop and boat/paddle traffic, sharp wreckage in shallow water, cold water

Reviews

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