PART ONE THE DANISH STRAITS CHAPTER I. THE TOPOGRAPHY, GEOGRAPHICAL FUNCTION AND POLITICAL HISTORY OF THE STRAITS Section I. The topography of the Straits. By the Danish Straits we mean the three natural passages, which unite the Baltic and the Kattegat (the North Sea). From west to east the passages are the Little Belt, the Great Belt and the Sound (i). THE .LITTLE BELT is the stretch of water between Jutland-Als on the one side and Fyen-Aar6 on the other. It is separated from the Kattegat by a line from Aebelo to B j6rnsknude (9-7 km) and from the Baltic by a line from Pols-Puk on Als to Vejsnaes Nakke on Aero (23.3 km) (2). The width of the Belt varies from about 700 metres to about km at its southern outlet. But various islands, in particular Aaro on the Jutland side and Bogo on the Fyen side, divide it into channels which are considerably narrower. Of these the ones most used for navigation are Aarosund between the coast of Jutland and Aaro (at the narrowest point about 3 km wide) and Bogosund between Bogo and the coast of Fyen (at the narrowest point about 3 km wide). The channels are often still further restricted owing ( i ) The phrase, the Danish Straits, is not quite accurate since the eastern shore of the Sound is Swedish. But it will be used in the following pages as it has acquired a sort of customary meaning and also corresponds to reality since the Danish channels are the most important also in the case of the Sound. (2) The following information is mainly based upon the information given in the "Den danske Lods" 1925 and later supplements 4 to shoals. In many places therefore navigation has often to take place in quite narrow channels as e. g. in Aarosund in a channel only about 3 So metres wide between 6 metre contours. - The current in the Belt is both very strong as much as 3 - metres a second. and very unreliable. A special characteristic is that it does not follow the course of the fairway but owing to bays in the course of the Belt across it from shore to existing zig-zags ' shore ("eddies").. The depth is r 6-r 8 metres in the northern part of the Belt and gradually increases, as the Belt becomes narrower, to as much as 81 metres, again decreasing to I5-I8 metres in its southern and wider portion. Thus, as far as depth is concerned, even the largest vessels can pass through the whole length of the Little Belt( I ). THE GREAT BELT is the stretch of water between Fyen-Lange- land on the one side and Zealand-Lolland on the other. It is separated from the Kattegat by a line Fyens Hoved-Refsnaes (about 22.2 km) and from the Baltic by a line Gulstav Flak on Langeland to the shore of Lolland off Kappel Church (about km). The Belt is separated from the waterway between Zea- land and Lolland ("Smaalandshavet") by a line which com- mencing at Korsor Church crosses the west coast of the island of Egholm and along its western side to the southern point of Onse- vig on Lolland (about 22 km). The area between this line and Langeland is usually called the Langeland Belt. The width of the Belt varies from km to 28.2 km. Between. Knudshoved on the Fyen side and Halskov on the Zealand side, where the Belt is 16 km wide, it is divided by Sprogo into two passages of almost equal width, "Vesterrenden" (between Fyen (Knudshoved) and Sprogo), and "Osterrenden" (between Sprogo and Zealand (Halsskov)). The width in the different channels is restricted, as in the Little Belt, owing to shoals. Thus the navigable channel in the Vesterrenden between Knudshoved and Sprogo is only about 3.3 km wide, in the Osterrenden between Sprogo and Halskov only about 1700 metres and between the reefs outside Agerso and Vengeancegrund only about 1800 metres (between io metre contours). (1) Since the building of the Little Belt Bridge (opened May i 5th, 193 5) ships with masts more high cannot the Belt, see as to this than 3 3 metres pass' through post. .