Suez Canal tonnage. The main purpose of the special measurement system is to establish criteria which determine the owner’s liability to pay Suez Canal tolls.
These were, raised to take effect on 1 January 1991. The tolls are expressed in “Special Drawing Rights” (SDRs) per Suez Canal Nett Ton (SCNT) and vary whether the vessel is laden or in ballast. There are a number of similarities and some significant differences with the British system of tonnage measurement. An example of the latter is the treatment of double bottom tanks. These spaces are not included in the British system but if these spaces are used for cargo or bunkers during a Canal transit, they are added to the SCNT for that transit.