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Great Isaac

New Jersey, United States
AOW suggested23–27 m (75–90 ft) depthBoat entry7mm or semi-dry + hood typical

Boat dive — see Entry & access.

Great Isaac at a glance

Great Isaac is an advanced boat dive site in New Jersey, United States with depths of 23–27.4 m (75–90 ft). Typically most favorable Jul · from 3 years of archive data. Divers commonly see wreck-associated fish, Lobster, and hydroids and anemones. Recent reports put the water around 17°C (62°F). Check the latest conditions and entry details before you go.

Favorable window now· until 18:00 · sunset 17:01

Forecast for this hour · 15:00 · run 3 h ago
1.0 m (3.3 ft)waves — about a meter expected (waves — about three feet expected)

Tap a factor for its source and model point · Forecast 17°C · seasonal avg 19°C ( · Forecast 62°F · seasonal avg 66°F)

Site hazards: Offshore distance, current, cold bottom temperatures, variable visibility, boat traffic, fishing line/entanglement, sharp wreckage, and possible silt or snag hazards around exposed ribs and plates.

Read the full hazards ↓

Dive windows this week

Lightest wind: Wed
Mon13:00–18:00 favorable

1.0 m waves · 12 kn wind (3.4 ft waves · 12 kn wind)

Tue7:00–9:00 favorable, 9:00–13:00 moderate, 13:00–17:00 favorable

1.2 m waves · 17 kn wind (3.8 ft waves · 17 kn wind)

Wed7:00–17:00 favorable

0.9 m waves · 6 kn wind (2.8 ft waves · 6 kn wind)

Thu7:00–17:00 favorable

0.6 m waves · 8 kn wind (1.9 ft waves · 8 kn wind)

Fri7:00–10:00 moderate, 10:00–17:00 favorable

0.6 m waves · 10 kn wind (2.1 ft waves · 10 kn wind)

Sat7:00–17:00 favorable

0.7 m waves · 11 kn wind (2.1 ft waves · 11 kn wind)

Sun7:00–17:00 favorable

0.7 m waves · 12 kn wind (2.2 ft waves · 12 kn wind)

Favorable windowModerate window— no window

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

First light 5:50 · Sunrise 6:17 · Sunset 17:01 · some windows run past sunset

Source: Open-Meteo marine · model point 5.3 km from site · updated 26 Oct, 12:26 GMT-5

Forecast only — always assess conditions on site.

Compare this weekend’s windows near Great Isaac

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: wreck-associated fish, hydroids and anemones
Best time: Best in settled summer/fall weather windows when offshore seas and current are manageable; verify visibility and current with the charter before departure.

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, 35% of days have historically been favorable, water has typically been 6°C (43°F), waves have typically been 1.5 m (4.9 ft), wind has typically been 21 knots
  2. February, 32% of days have historically been favorable, water has typically been 5°C (42°F), waves have typically been 1.5 m (5.0 ft), wind has typically been 21 knots
  3. March, 28% of days have historically been favorable, water has typically been 6°C (44°F), waves have typically been 1.6 m (5.4 ft), wind has typically been 21 knots
  4. April, 43% of days have historically been favorable, water has typically been 9°C (49°F), waves have typically been 1.4 m (4.7 ft), wind has typically been 20 knots
  5. May, 67% of days have historically been favorable, water has typically been 14°C (57°F), waves have typically been 1.3 m (4.1 ft), wind has typically been 17 knots
  6. June, 71% of days have historically been favorable, water has typically been 18°C (65°F), waves have typically been 1.1 m (3.6 ft), wind has typically been 17 knots
  7. July, 76% of days have historically been favorable, water has typically been 23°C (73°F), waves have typically been 1.0 m (3.3 ft), wind has typically been 16 knots, historically most favorable
  8. August, 65% of days have historically been favorable, water has typically been 22°C (72°F), waves have typically been 1.3 m (4.1 ft), wind has typically been 17 knots
  9. September, 44% of days have historically been favorable, water has typically been 22°C (71°F), waves have typically been 1.6 m (5.1 ft), wind has typically been 18 knots
  10. October, 46% of days have historically been favorable, water has typically been 19°C (66°F), waves have typically been 1.6 m (5.1 ft), wind has typically been 19 knots
  11. November, 44% of days have historically been favorable, water has typically been 14°C (58°F), waves have typically been 1.3 m (4.3 ft), wind has typically been 21 knots
  12. December, 42% of days have historically been favorable, water has typically been 9°C (48°F), waves have typically been 1.5 m (4.9 ft), wind has typically been 21 knots

July 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 July 2026

Site details

Great Isaac is a large V4-M-A1 ocean tug wreck off southern New Jersey. NJScuba describes the wreck in about 90 ft / 27 m, lying on its port side and partly buried, with exposed ribs and structure. This is an offshore wreck dive for experienced divers, not a beginner reef stop.

boatwreck

Offshore distance, current, cold bottom temperatures, variable visibility, boat traffic, fishing line/entanglement, sharp wreckage, and possible silt or snag hazards around exposed ribs and plates.

Reviews

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