A fuel surcharge clause (Dieselfloater in German) automatically adjusts the freight rate to changes in the diesel price. When diesel rises or falls against an agreed base price, a surcharge on the freight changes.
Structure: base diesel price, reference index (e.g. a published average price), adjustment interval (such as monthly) and the fuel share of freight cost.
Example: if fuel is 30% of the freight and diesel rises by 10%, the freight rate rises by 3%.
Why it matters: fuel is one of the largest cost items. Without a surcharge clause, the carrier bears the price risk alone.