This paper discusses the results from extensive wake wash measurements carried out with a model of a ROPAX ship passing a bay. The tests were carried out in SSPA’s sea-keeping and maneuvering basin. This model had been subjected to wash wave measurements in open water in previous tests, which gave possibilities for comparisons between restricted and unrestricted waters. Six wave gauges were placed inside and outside the bay, and a significant drawdown was noticed in addition to amplifications of the Kelvin waves. The drawdown and the Kelvin waves that occurred in the bay are difficult to explain, but this paper makes an attempt to analyze the phenomena that occur. The different wave theories that can be used in this case are presented. The methods that are used for analyzing the measured signals are described. One conclusion that can be made is that drawdown caused by the Bernoulli wave can probably be considered a worse problem than ordinary wash waves (Kelvin waves) in restricted and especially shallow waters when looking at large displacement ships.