In the case a sea harbor is located in an inland area, seagoing vessels have to sail a part of their journey in inland waterways. On thee approach channels the inland water regulation prescribes specific bridge equipment. Inland vessels fulfill this regulation, the seagoing vessels not, but get dispensation with a pilot on board. The question arises how differences in working strategy (resulting from different ship characteristics and equipment) express in differences in workload. The effect of changes in environmental bank lights (puddle lights) on both inland skippers and pilots is studied in a manoeuvring simulator using physiological workload measurements. Event analysis is based on a combination of analytical indicators (distance between vessels) and cognitive processes like interpreting perceived visual information. Results demonstrated that the effect of change in puddle light is different for skippers and pilots. Differences in vessel and bridge settings are indeed expressed in working strategy and result in differences in workload. Inland skippers give effort to continuous steering corrections and are compared to the pilots, less used to anticipate on future actions. In the absence of puddle light, the skippers mental spare capacity decreases clearly. Although the subjective opinion of the pilots indicate an increase of demand, the objective measures do not show a considerable increase.