Aquatic Research

Öz

Strait of
Istanbul is one of the most difficult waterways in the world. It’s curved
structure, sharp bends which require 12 major course alterations form a unique
marine environment for passing vessels. Currents also form a natural difficulty
for navigation, especially at areas at the North of Kandilli point. There are three
types of currents prevail in the Strait of Istanbul: the first is the surface
currents, which finds it’s dynamics at the difference of sea levels between Sea
of Marmara and Black Sea. Due to this difference in levels, which is around 40
centimeters on average and fed by the rivers flowing into Black Sea, waters run
down to Sea of Marmara and to outer seas. Second, is the counter currents and
eddies inside the bays. Third is the subsurface currents, formed by the
difference of salinity between Marmara and Black Sea, starts from 10 meters to
40 deep and in counter direction with the surface currents. To make this
currents system more complicated, in the case of strong SW winds when lasted
more than 2-3 days, the whole currents system changes when the surface currents
reversed by the wind and above-mentioned difference in sea levels exchange
positions to the favor of Sea of Marmara. 
Due to this unique system of currents, Strait of Istanbul used to have a
unique navigational system, too. Starting from ancient times, ships navigating
in the Strait of Istanbul used to navigate on the Port side, especially when
navigating from Sea of Marmara to Black Sea direction. Thus, ships could get better protection against current. This practice was inked on the
paper in 1933 and by the Istanbul Port Regulation through which it became
compulsory for ships navigating in the Strait of Istanbul. But as the
international regulations on the preventing collision at sea emerged and it
appeared that right-hand navigation was established for narrow channels and
altering the course to Starboard in the head-on situations has become a rule,
the Left-hand side navigation in the Strait of Istanbul started to lead to
confusion. There have been three major accidents in the Strait of Istanbul
which could be attributed to confusion created by this national rule against
the international rule; in 1960, 1966 and 1979, finally Left-hand side
navigation in the Strait of Istanbul was abolished in 1982. This article is
about these long-term proceedings of Left-hand side navigation in the Strait of
Istanbul, concentrating on and analysing three major accidents.