The mathematical modelling of maritime supply is crucial for the understanding of freight rate mechanism and to cope with maritime market cycles. Thus, the recognition of the maritime supply function enables ship operators to forecast freight rates and to optimize their voyage costs by fixing tweaking the vessels speed in order to optimize their maritime operations. However, a suitable maritime supply model emanates beyond economic issues in maritime sector since it also unfolds the relationship between speed and transport capacity in whole logistics sector. Literature review reveals that several approaches from a large number of scholars exist to model supply functions but most of them are based on statistical analysis of empiric data of the maritime markets making it complicated to integrate the supply function into mathematical frameworks as well as to extrapolate the found model. This research follows the analytical approach for modelling the maritime supply function based on the VUT formula well known from queuing theory. After a discussion of the elaborated model the results are empirically validated by data gathered within several EU projects on maritime logistics with a focus on Baltic Sea Region.