Sønderborg
Sonderborg · Sønderborg Havn · Sønderborg Slot
54°54.5'N 09°47.4'E
Depth
3–5m
Bottom
mud
Alarm Radius
65m
Holding
Good
Recommended Anchor Alarm Radius
65m
65m for Als Sund anchorage in 3–5m. Monitor ferry and recreational boat traffic through the sound — the boat may swing on current as well as wind. In easterly above F4, move into the harbour.
Setting Your Anchor
- 1.Check eelgrass chart (DKSOS app or Navionics) — anchor only on sandy or muddy bottom free of vegetation
- 2.Use 5:1 scope minimum — the Little Belt is almost tideless (0.3–0.5m tidal range); scope is about depth and holding, not tide
- 3.Remember: anchoring is tolerated for 1 night only in unoccupied natural anchorages — it is not a legal right in Denmark
- 4.Set your anchor alarm to 65m before sleeping — tidal currents through the narrows can cause unexpected swinging
About This Anchorage
Sønderborg is the largest city on Als island and the main gateway to South Jutland from the sea. Sønderborg Castle (Sønderborg Slot) is one of Denmark's finest medieval fortresses, built in 1170 and housing the museum of the 1864 war. The Als Sund connects the Baltic with Als Fjord, with moderate shipping and recreational traffic. The harbour is large and well-equipped. The city has full urban services — an excellent base for exploring South Jutland. The Dybbøl battlefield (site of the decisive 1864 battle, 3km west) is a national memorial site.
Protected From
N · NW · W · SW
Exposed To
E · SE · NE
Anchoring Rules
- Anchoring fee
- Free (anchoring in Als Sund); harbour fee approx DKK 160–200/night
- Permit required
- No
Restrictions: Als Sund has ferry traffic — maintain clear passage; no anchoring in the main navigation channel; anchoring tolerated 1 night; speed limit 5kt within 300m of shore; VHF 12.
Hazards
- !Ferry and recreational traffic through Als Sund — anchor clear of the main channel
- !Open to east across Als Sund — uncomfortable in easterly above F4
- !Busy anchorage area in July–August — arrive before 15:00 for best position
- !Eelgrass fringe on shallow areas — anchor in deeper sandy mud
Skipper's Tips
- →Sønderborg Slot museum is Denmark's finest museum of the 1864 war — the 3D panorama of the Dybbøl battle is extraordinary
- →Cycle to Dybbøl (3km west) — the windmill at Dybbøl Mølle is the symbol of Danish resistance; the national memorial is moving
- →Sønderborg waterfront has been comprehensively regenerated — the ALS RESEARCH PARK marina area is excellent for a city stop
- →The Sønderborg–Flensburg water bus runs in summer — day trip to the German city is straightforward
Facilities
Sønderborg has multiple restaurants, cafes, and supermarkets. Excellent harbour-side restaurants. Full chandlery and marine services.
Nearest provisions: Sønderborg town centre (0.5nm)
Best Months & Season
May, June, July, August, September
May–September. Sønderborg is the essential stop for sailors interested in Danish history — the 1864 war shaped modern Denmark and its aftermath created the current border.
Recommended Anchor Types
Nearby Anchorages
Set Your Anchor Alarm to 65m
In the Little Belt, tidal currents and eelgrass proximity require constant vigilance. Safety Anchor Alarm monitors your GPS position continuously.
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