43Lastly, as regards proportionality, the VTS system, in that it requires the payment of a VTS tariff by seagoing vessels longer than 41 metres, fulfils that criterion in so far as there is in fact a correlation between the cost of the service from which those vessels benefit and the amount of that tariff. This would not be the case where that amount included cost factors chargeable to categories of ships other than seagoing vessels longer than 41 metres, such as, in particular, inland waterway vessels.