1960
WHOI

	On July 29,1960 we entered the Baltic Sea
and passed Kronstad, Hamlet's Castle

The sill depth between the Baltic Sea and the North Sea is only 18 meters, so the Baltic is brackish because of the many rivers debouching into it. Its circulation is poor and major salt intrusions occur about once a decade. Pollution problems abound, but fortunately UNEP's "Regional Seas" Programme and other joint efforts are in force. In 1992, the updated Helsinki Convention was signed and the Baltic Sea Joint Comprehensive Action Programme adopted.