The Kiel Canal, the shortcut a Kaiser dug

Denmark's Jutland peninsula sits directly in the way of any ship sailing from the North Sea to the Baltic, forcing a choice between two lengthy detours around it, via the Skagerrak and Kattegat to the north, or the narrow, current-prone straits between the Danish islands, either of which could add the best part of a day to a voyage and expose a ship to open water it might otherwise have avoided. The Kiel Canal solves the problem directly, cutting across the base of the German peninsula of Schleswig-Holstein to link the North Sea at Brunsbüttel with the Baltic at Kiel, a distance of just under a hundred kilometres that removes the need to go around Denmark at all.

Built for a navy, used by everyone else

The canal in its current form was constructed between 1887 and 1895, funded and pushed through by Kaiser Wilhelm II's Imperial German government primarily for naval reasons: a fast, sheltered route between the Baltic and North Sea fleets that avoided both the Danish detour and the risk of a hostile power blockading the straits in wartime. It opened in 1895, was substantially widened in the early twentieth century to accommodate the larger battleships then entering service, and has remained continuously open and in commercial use ever since, surviving two world wars and a change of country's entire political system without ever losing its basic function as Europe's most heavily used artificial waterway, carrying, by most measures, considerably more ship traffic each year than the Panama and Suez canals combined, most of it smaller commercial and leisure vessels rather than the naval giants it was originally dug for.

A passage that takes most of a day

For a cruise passenger, transiting the Kiel Canal is less a single dramatic moment than a slow, absorbing day spent watching an ordinary stretch of northern German countryside pass close by on either side: farmland, small towns, road and rail bridges crossing high overhead, and a steady procession of other shipping moving in both directions along a channel narrow enough that the passing traffic feels considerably closer than it does on open water. The canal has no locks along its main length beyond the sea gates at either end, so the passage itself is gentle rather than technically dramatic, and it is precisely that unhurried, close-up view of inland Germany, normally invisible from a ship's deck, that gives the crossing its appeal.

What the canal replaced

Before 1895, a ship's captain heading for the Baltic had to weigh the shorter but more hazardous strait route against the longer, safer passage north of Denmark, a decision that shipping records suggest was made differently depending on the season, the cargo and, not infrequently, the captain's own nerve. The canal removed the dilemma almost entirely, and Denmark's straits, once a compulsory chokepoint for Baltic-bound traffic, reverted to a route used mainly by vessels too large for the canal's locks or by ships already heading that way for other reasons, a reminder that a single piece of nineteenth-century engineering can quietly redraw shipping patterns that had held for centuries beforehand.

Sailing the canal

Fred. Olsen's Discovering the Baltic with the Kiel Canal, eleven nights from Rosyth, uses the canal as its route into the Baltic, calling at Tallinn and Ventspils on the far side.

Countries & Cultures of Northern Europe, ten nights from Southampton, follows a similar route, transiting the canal en route to Gdańsk and Copenhagen.

A full day on deck is the best way to appreciate the crossing properly; the canal moves too slowly for it to reward a brief look, and rewards a patient one considerably more than most passengers expect.

The canal today is managed by German federal authorities rather than by any naval command, a fairly complete reversal of the institution that first funded it, and it remains free to use for any vessel, naval or civilian, that meets the size restrictions, still roughly the limit set by the locks built during the early twentieth-century widening rather than by anything more recent. It is, in that sense, one of the few pieces of large-scale nineteenth-century military infrastructure anywhere in Europe that has spent considerably longer serving ordinary commerce and passenger traffic than it ever spent serving the fleet it was dug for.