Worldwide Tanker Nominal Freight Scale. Worldscale Association, a shipping industry group, publishes a lengthy schedule of rates for popular tanker voyages. The printed figures, called World scale 100's, reflect application of tanker operating cost assumption to the ports and distance/steaming time on route. These “flat rates” appear in US dollars per ton of cargo. Shipowners and spot charterers usually negotiate the hire price of a tanker as percentage of Worldscale 100 for the voyage involved. They might fix at Worldscale 40 (WS 100 x2.00), or any other number dictated by size and kind of ship, market conditions, and negotiating skill.

An international freight index for tankers. Abbreviation: WS.

the code name for Worldwide Tanker Nomimal Freight Scale; this system brings out bi-annually revised scales of freights based on the cost of operating a standard tanker to and from some known ports