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Map of Mary Alice B Wreck (Sanilac Shores Underwater Preserve)
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Mary Alice B Wreck (Sanilac Shores Underwater Preserve)

Michigan, United States
AOW suggested26–29 m (85–95 ft) depthBoat entry

Boat dive — see Entry & access.

Mary Alice B Wreck (Sanilac Shores Underwater Preserve) at a glance

Mary Alice B Wreck (Sanilac Shores Underwater Preserve) is an advanced boat dive site in Michigan, United States with depths of 25.9–29 m (85–95 ft). Typically most favorable Sep · from 3 years of archive data. Divers commonly see Round goby, Smallmouth bass, and Zebra/quagga mussel. Check the latest conditions and entry details before you go.

Favorable window now· until 10:00, then moderate until 19:00 · sunset 18:29

Wind forecast for this hour · 9:00 · run 19 h ago
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Tap a factor for its source and model point

Site hazards: Depth, dark cold water below thermocline, silt-out risk inside pilothouse, entanglement

Read the full hazards ↓

Dive windows this week

Mon8:00–10:00 favorable, 10:00–19:00 moderate

15 kn wind (15 kn wind)

Tue8:00–19:00 favorable

7 kn wind (7 kn wind)

Wed9:00–19:00 favorable

9 kn wind (9 kn wind)

Thu11:00–18:00 moderate, 18:00–19:00 favorable

14 kn wind (14 kn wind)

Fri9:00–19:00 favorable

12 kn wind (12 kn wind)

Sat9:00–19:00 favorable

4 kn wind (4 kn wind)

SunNot in the forecast yet

Favorable windowModerate window— no window

Every forecast dive window each day, site-local time, from wind forecasts. Numbers under each bar are daylight averages.

First light 7:28 · Sunrise 7:57 · Sunset 18:29 · some windows run past sunset

Source: Open-Meteo wind · updated 25 Oct, 13:24 GMT-4

Forecast only — always assess conditions on site.

Compare this weekend’s windows near Mary Alice B Wreck (Sanilac Shores Underwater Preserve)

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: Round goby, Zebra/quagga mussel, Burbot
Best time: June-September

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. January, 55% of days have historically been favorable, wind has typically been 14 knots
  2. February, 52% of days have historically been favorable, wind has typically been 14 knots
  3. March, 47% of days have historically been favorable, wind has typically been 14 knots
  4. April, 57% of days have historically been favorable, wind has typically been 14 knots
  5. May, 73% of days have historically been favorable, wind has typically been 12 knots
  6. June, 80% of days have historically been favorable, wind has typically been 12 knots
  7. July, 88% of days have historically been favorable, wind has typically been 10 knots
  8. August, 87% of days have historically been favorable, wind has typically been 10 knots
  9. September, 92% of days have historically been favorable, wind has typically been 10 knots, historically most favorable
  10. October, 74% of days have historically been favorable, wind has typically been 12 knots
  11. November, 48% of days have historically been favorable, wind has typically been 14 knots
  12. December, 49% of days have historically been favorable, wind has typically been 14 knots

September has typically 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

Rough labels: “Commonly seen” usually means two or more recorded sightings near this site in public dive logs (GBIF), “Occasionally seen” one; “Seasonal” and “Rarely seen” come from dive-guide research. Not a measured rate.

Fills & rentals nearby

No dive shops mapped within 25 km (16 mi). Know one? Add it to the map.

Data updated June 2026

Site details

The Mary Alice B is a 62-ft steel tug built in 1931 for the Army Corps of Engineers (originally named Quintus) that foundered off Port Sanilac in September 1975 and was located in 1992. She sits upright and remarkably intact in about 92-95 ft of Lake Huron within the Sanilac Shores Underwater Preserve. The pilothouse, with the wheel still in place, offers a swim-through for trained divers, though silt is easily disturbed inside.

boatwreck

Depth, dark cold water below thermocline, silt-out risk inside pilothouse, entanglement

Reviews

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