All ships being assigned class with INSB shall be given a class notation consisting of a construction symbol, a main character of class, service area restriction notations and main ship type notations, and entered into the INSB Register Book.

Assignment of class, classification characters and notations, which denote the degree of confidence that the ship deserves, are assigned following the satisfactory completion of surveys carried out by the society’s surveyors and the completion of verification of compliance with the INSB rules. INSB class notations cover both mandatory and optional requirements.

Class notations may be also assigned with a supplemental symbol. Such a supplemental symbol shall be used to identify special requirements or limitations related to the class notation.

Constructional details and technical features of the ship entering into Class are recorded in the Certificate of Class and other documents issued by the INSB.

Typically, the INSB class notation include the following:

  • Construction marks.
  • Class symbols:

Hull character

Machinery installation character (as applicable)

Division number

Rating letter

Equipment symbol

  • Service notations.
  • Navigation notations.
  • Additional notations
  • A combined service notation, which may be assigned to a ship when requirements for each service notation are met.
  • Special notations which may be assigned upon request from the party applying for classification, indicating that the ship or some of her arrangements and/or installations comply with specific International, National or other regulations that are not necessarily covered by the INSB Rules.
  • Machinery Installations which comply with the Rules of the society for automated and/or remote controlled systems, shall be designated an additional class notation affixed to the Classification character.

INSB Class notations are listed in the society’s Rules for the Construction and Classification of Steel Ships-Part I.