Sailing the Baltic: South Funen Archipelago, Schlei and Kiel Bay

The western Baltic, from Kiel Bay, the Schlei and Flensburg Fjord to the South Funen Archipelago, is an area of short daily legs: harbours are often only 5 to 25 nm apart, tides are negligible and the wind sets the water level. Sailing is May to September, mostly in W to SW winds; plan for bridges, firing ranges and ferries.

Which cruising areas make up the western Baltic?

Six areas line up between Kiel and Copenhagen, each a day's sail from the next. The harbour pages show depth, services and the local weather.

The South Funen Archipelago, known to German sailors as the “Danish South Sea”, is the heart of the area: Ærø, Langeland, Tåsinge and the small islands south of Funen lie so close together that Marstal and Ærøskøbing are less than 5 nm apart as the crow flies. Outside the buoyed channels it quickly gets too shallow for a keelboat. In the Svendborgsund there is often a strong current, spanned by the fixed Svendborgsund bridge with 33 m clearance.

In the Belts things get more serious. The Great Belt is the main route for large ships into the Baltic; the East Bridge of the Great Belt Bridge gives 65 m clearance, the West Bridge only 18 m. In the Little Belt near Middelfart two fixed bridges give 33 and 42 m, and beneath them the current sometimes runs at several knots.

How does the wind blow in the western Baltic?

In summer west to southwest winds predominate, around force 3 to 4 on quiet days, with a sea breeze along the coast on warm days. When lows pass through it freshens to 6 Bft and more and veers northwest behind the front. Easterly situations usually bring settled, dry weather.

Because the water is shallow, a short, steep sea builds quickly. Upwind in Kiel Bay, the Fehmarn Belt and the Great Belt it gets wet and slow from 5 Bft. In high summer thunderstorms with strong gusts are added; more in Gusts and thunderstorms. Plan a reserve day, see Weather window.

Are there tides in the Baltic?

Hardly: in the western Baltic the tide is so small that it does not count next to the wind. The weather sets the water level.

Persistent west to southwest winds push water out of the western Baltic and make the level drop in the fjords and bays. Strong east to northeast winds raise it, in extreme cases to a storm surge as in October 2023. The depths on the chart and in the pilot book apply at mean water level; after a westerly gale, shallow approaches in the islands and the Schlei get tight.

There is current nonetheless. In the Belts and the Øresund the wind and the difference in water level between the Baltic and the Kattegat drive the water, at several knots in strong winds. It sets north or south, but not by the clock as in the North Sea. More in Tides and tidal streams.

When do the bridges on the Schlei and the Alssund open?

Bascule bridges open to a timetable, and fixed bridges limit mast height. The most important in the area:

If you are heading for Schleswig, plan around Lindaunis: the temporary bridge only opens during the day, and in winter the construction site is closed to shipping. Times change with construction work and maintenance. The authoritative sources are the Notices to Mariners (Bekanntmachungen für Seefahrer, BfS) of the WSA Ostsee, Germany's waterways and shipping office for the Baltic, in ELWIS, and for Denmark the Havnelods.

From the North Sea you come through the Kiel Canal and the Kiel-Holtenau lock. Pleasure craft may only transit during daytime hours; in 2026 the transit fee is 12 to 43 euros depending on length, and it will be abolished from 2027. Details in the guide Bridges and locks.

What applies in firing ranges and restricted areas?

The navy exercises off the coast. Some areas are permanently closed, others only during the announced firing times.

• Germany: The Putlos and Todendorf danger areas in Hohwacht Bay are closed during firing times; the WSA Ostsee publishes the times weekly as BfS in ELWIS. In addition there is the danger area of the torpedo range off Eckernförde and small, permanently closed areas in Kiel Fjord, for example off Friedrichsort and Kiel-Wik.
• Denmark: The Danish Maritime Authority (Søfartsstyrelsen) announces the firing times of the Danish firing and exercise areas in its navigational warnings (Niord). On top of that come wildlife reserves (vildtreservater), where navigation or landing is prohibited at certain times; the boundaries are on the chart and in the Havnelods.

Which formalities apply between Germany and Denmark?

No clearance: both countries are in the Schengen area and the EU customs union. If you arrive from a country outside the EU, including Norway, report to customs at the first harbour.

On board you need the boat papers, proof of insurance, the SRC for the radio and a licence: in German waters the Sportbootführerschein See for engines from 15 hp, while in Denmark the rules of your home country apply. In Danish harbours you usually pay the harbour dues (havnepenge) at a machine or via an app, and a green or red sign at the berth shows whether it is free. The emergency number is 112; on VHF channel 16 the DGzRS (MRCC Bremen) listens, and in Denmark JRCC Denmark and Lyngby Radio. Everything else is on the country pages Germany and Denmark.

How does Sailseer help with a Baltic sailing trip?

On the map you plan from harbour to harbour. On entering and leaving harbour the route follows the buoyed channels, factors the opening times of Kappeln, Lindaunis and the Danish bascule bridges into the passage time and takes closures from the BfS into account. If a firing range is active at the time you pass, the route goes around it, at Putlos and Todendorf with a detour of about 4 nm north of Hohwacht Bay. Sailseer also shows the forecast of several weather models, the DWD marine forecast, warnings from DWD and DMI, water levels and wind from Pegelonline, BSH and DMI, currents from the Copernicus Baltic model and anchorages with their shelter for each wind direction.

Sailseer is a planning aid and not for navigation. Official charts, the marine forecast, the warnings from DWD and DMI and the Notices to Mariners always take precedence. How to put a trip together is covered in Passage planning step by step.