The application of the Zone/Date System (Z/DS) is described under the Arctic Shipping Pollution Prevention Regulations. It divides the Canadian Arctic waters into sixteen Shipping Safety Control Zones, and stipulates the opening and closing dates for each zone in each of nine Arctic Class ships, and five Type ships. These dates form the Dates of Entry Table.
The Z/DS is based on the premise that nature consistently follows a regular pattern year after year. It defines the following:
- Sixteen zones of increasing severity
- Nine Arctic Classes and five Type (Baltic) Ships
- Opening and closing dates for each class of ship
The Z/DS is a fixed system that does not reflect long term trends and inter-annual variability in ice conditions. Due to this constraint, in 1996 Transport Canada introduced the more flexible Arctic Ice Regime System (AIRSS) . Ships may continue to use the Dates of Entry Table for basic passage planning for estimating when certain ice conditions may occur. AIRSS is currently used only when making access decisions outside of the established dates.
Zone/Date System Map and Dates of Entry Table