3.1 The Torres Strait, including the Great North
East Channel, is used primarily by large vessels trading between ports
in southern Asia, Australia and New Zealand, South America, Papua
New Guinea and Pacific Island nations although the majority of tanker
traffic bound for the Australian east coast refineries also uses it
to link with the outer route of the Great Barrier Reef. Vessels entering
or leaving the inner route of the Great Barrier Reef also use the
Prince of Wales Channel at the western end of the Torres Strait.
3.2 Parts of the Torres Strait are isolated, remote
and very demanding on the navigator. Passage through these waters
also involves navigation within confined waters for long periods,
with limited depths of water being a constant threat. The average
depth of the Torres Strait is 30-50 metres in the east and 10-15 metres
in the west. Tidal streams can be strong and variable. Most of the
region has a monsoon climate and visibility is frequently adversely
affected by seasonal rain squalls. The area as a whole is subject
to seasonal tropical storms and cyclones.
3.3 There are narrow fairways and areas of converging
traffic that, while not heavy by some standards, represent a wide
range of ship types, carrying a variety of cargoes, including dangerous
goods and potentially polluting materials. Ships navigating the area
may encounter concentrations of fishing vessels, tourist vessels and
recreational craft that, by their very numbers, increase the dangers
of marine incidents.
3.4 A spill occurred in Prince of Wales Channel
in 1970 (Oceanic Grandeur) and numerous other groundings
and near misses have occurred due to the combination of shallow water,
narrow channels, strong tidal streams and strong winds.
3.5 The current recommended maximum draft for
ships passing through Gannet Passage is 12.2 metres which, for a large
percentage of ships, provides an underkeel clearance of one metre
at the higher stages of the tide cycle. Careful calculations are required
by Masters and pilots of deep draft vessels to establish the timing
of "tidal windows" for their passage through the Strait.
3.6 A detailed description of the characteristics
of the maritime traffic, the transport of harmful substances, and
the threats from disasters, including a description of the meteorological,
oceanographical and geographical conditions may be found in paragraphs
4.1 to 4.3 of document MEPC 49/8.