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Map of Harbor of Refuge Breakwater (Outer Wall)
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IntermediateBoat entry

Harbor of Refuge Breakwater (Outer Wall)

Delaware, United States
Open Water suggested2–18 m (5–60 ft) depthBoat entry7mm or semi-dry + hood typical

Boat dive — see Entry & access.

Harbor of Refuge Breakwater (Outer Wall) at a glance

Harbor of Refuge Breakwater (Outer Wall) is an intermediate boat dive site in Delaware, United States with depths of 1.5–18.3 m (5–60 ft). Typically most favorable Jul · from 3 years of archive data. Divers commonly see Black drum, Sheepshead, and Blue mussel. Recent reports put the water around 16°C (61°F). Check the latest conditions and entry details before you go.

Next window today· 8:00–19:00 · favorable · sunset 18:08

Forecast for this hour · 7:00 · run 6 h ago
0.8 m (2.6 ft)waves — under a meter expected (waves — about three feet expected)

Tap a factor for its source and model point · Forecast 16°C · seasonal avg 18°C ( · Forecast 61°F · seasonal avg 65°F)

Site hazards: Tidal currents sweeping the wall, boat traffic entering the harbor, swell wrapping the structure, sharp barnacle- and mussel-covered rocks, fishing line

Read the full hazards ↓

Dive windows this week

Sun8:00–19:00 favorable

0.8 m waves · 5 kn wind (2.5 ft waves · 5 kn wind)

Mon8:00–19:00 favorable

0.6 m waves · 4 kn wind (2.0 ft waves · 4 kn wind)

Tue8:00–19:00 favorable

0.7 m waves · 9 kn wind (2.1 ft waves · 9 kn wind)

Wed8:00–19:00 favorable

0.7 m waves · 8 kn wind (2.2 ft waves · 8 kn wind)

Thu8:00–19:00 favorable

0.4 m waves · 5 kn wind (1.3 ft waves · 5 kn wind)

Fri8:00–19:00 favorable

0.3 m waves · 3 kn wind (1.0 ft waves · 3 kn wind)

Sat8:00–19:00 favorable

0.6 m waves · 8 kn wind (1.9 ft waves · 8 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 6:52 · Sunrise 7:20 · Sunset 18:08 · some windows run past sunset

Source: Open-Meteo marine · model point 5.1 km from site · updated 25 Oct, 01:23 GMT-4

Forecast only — always assess conditions on site.

Compare this weekend’s windows near Harbor of Refuge Breakwater (Outer Wall)

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: Blue mussel, Tautog (blackfish)
Best time: Late spring through fall; black drum run is May-June

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, 56% of days have historically been favorable, water has typically been 4°C (39°F), waves have typically been 0.8 m (2.7 ft), wind has typically been 20 knots
  2. February, 58% of days have historically been favorable, water has typically been 5°C (40°F), waves have typically been 0.8 m (2.5 ft), wind has typically been 19 knots
  3. March, 52% of days have historically been favorable, water has typically been 7°C (45°F), waves have typically been 0.9 m (2.8 ft), wind has typically been 20 knots
  4. April, 69% of days have historically been favorable, water has typically been 12°C (54°F), waves have typically been 0.8 m (2.6 ft), wind has typically been 19 knots
  5. May, 88% of days have historically been favorable, water has typically been 18°C (64°F), waves have typically been 0.7 m (2.2 ft), wind has typically been 16 knots
  6. June, 89% of days have historically been favorable, water has typically been 23°C (73°F), waves have typically been 0.6 m (2.0 ft), wind has typically been 16 knots
  7. July, 94% of days have historically been favorable, water has typically been 27°C (81°F), waves have typically been 0.5 m (1.7 ft), wind has typically been 14 knots, historically most favorable
  8. August, 91% of days have historically been favorable, water has typically been 26°C (79°F), waves have typically been 0.6 m (2.1 ft), wind has typically been 15 knots
  9. September, 92% of days have historically been favorable, water has typically been 24°C (74°F), waves have typically been 0.7 m (2.4 ft), wind has typically been 15 knots
  10. October, 73% of days have historically been favorable, water has typically been 18°C (65°F), waves have typically been 0.7 m (2.4 ft), wind has typically been 16 knots
  11. November, 64% of days have historically been favorable, water has typically been 13°C (55°F), waves have typically been 0.8 m (2.5 ft), wind has typically been 18 knots
  12. December, 63% of days have historically been favorable, water has typically been 6°C (43°F), waves have typically been 0.8 m (2.5 ft), wind has typically been 18 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 June 2026

Site details

The mile-and-a-half-long outer breakwater off Cape Henlopen, built of more than a million tons of granite in the early 1900s to shelter the mouth of Delaware Bay. The submerged rock slope is heavily encrusted with mussels and attracts tautog, sheepshead, striped bass and record-class black drum, making it the region's storied freediving and scuba spearfishing site; the Gypsum Prince wreck lies at its seaward end. Depths along the wall run from the surface rocks down to about 40-70 ft on the surrounding bottom, with strong tidal flow around the structure.

boatwall

Tidal currents sweeping the wall, boat traffic entering the harbor, swell wrapping the structure, sharp barnacle- and mussel-covered rocks, fishing line

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