This paper presents the research results on declarative ship domains in restricted areas. The research was conducted
for vessels of different sizes and speed relations. In order to determine the declarative ship domain,
data were collected in the form of questionnaires. The influence of ship length and speed on the size and shape
of its domain were analyzed. The detailed processes of data development and further approximation are shown.
Declarative domains for ships of different sizes and speed relations are compared. As a result of the research,
a mathematical model of a declarative ship domain showing the elliptical shape of the domain is presented.
The intermediate and summary research results are presented and conclusions drawn.