The Ship Domain – A Criterion of Navigational Safety Assessment in an Open Sea Area

Abstract

One of the basic tasks in shipping is to ensure safe navigation of vessels. The concept of the ship domain is of major importance in the assessment of a navigational situation and the avoidance of ship collisions. It is difficult to determine a ship domain as its shape and size depend on a number of factors. One question to be answered before the determination of the ship domain is which method to use: statistical, analytic, or expert method using artificial intelligence tools; other questions are connected with domain interpretation. The authors have analyzed the ship domain as a criterion for the assessment of ship navigational safety in an encounter situation in the open sea. The research results are used to answer some of the questions.Part 2 includes definitions of the ship domain and ship fuzzy domain. Part 3, in turn, presents methods of their determination as well as relevant questions. The results of the authors' research, described in Part 4, make up a basis for the determination of the domain and ship fuzzy domain. These have been determined with the so-called dynamic domains as a point of departure. The criteria of ship domain and closest point of approach are compared and discussed. Encounters of various size ships are considered in Part 5. The research and its results are described. Both ship domains and ship fuzzy domains of encountering ships are analyzed. Then, conclusions have been formulated in relation to the effect of the sizes of encountering ships on the shapes and sizes of their domains. Final conclusions are given in Part 6.

Ship Domain as a Safety Criterion in a Precautionary Area of Traffic Separation Scheme

“…There are a number of methods for domain determination (Fuji & Tanaka 1971, Zhao et al 1993, Rutkowski 1998, Smierzchalski & Weintrit 1999, Zhu et al 2001, Pietrzykowski 2008, Pietrzykowski & Uriasz 2009, Wang et al 2009, Wielgosz & Pietrzykowski 2012, Hansen et al 2013, Wang 2013. These are mainly analytical, statistical and artificial intelligence methods.…”

Ship Domain Model for Multi-ship Collision Avoidance Decision-making with COLREGs Based on Artificial Potential Field

“…Since ship domain is a kind of image description of ship collision risk, it is reasonable to be changed with different ship speed and other navigation data. Pietrzykowski (Pietrzykowski and Uriasz 2009) defined a variable ship domain with different levels of safe growth and crewʹs consciousness. For example, the ship domain is smaller where the navigator is familiar with the waters, since it's safer than other scenarios.…”

A Model of Determining the Closest Point of Approach Between Ships on the Open Sea

“…In general, they responded that the domain for ships approaching from the starboard side was 1.8 M, and the action of avoidance would start at 4.3 M distance from another ship. The domain from port side was 1.6 M, and the distance for avoidance 2.6 M. Pietrzykowski, et al [9] presented graphically their research results (Figures 1 and 2) where two ships passed each other on the open sea at a safe distance. The figures show resizing of a domain when two ships of different sizes pass each other in relation to own ship.…”