Ice Class Strengthening of Existing Reefer Vessels Trading in the Baltic Sea : - A comparative study of ice classifications 1D and 1C

University essay from KTH/Skolan för teknikvetenskap (SCI)

Author: Dennis Bremberg; Sarah Högdahl; [2016]

Keywords: ;


This bachelor thesis strives to perspicuously answer what an ice strengthening of two different existing reefer vessels might mean for operations in the Baltic Sea and illustrate what factors a shipping company needs to consider when initiating such a project. The main purpose is to provide an information basis facilitating the communication between different parties in the shipping industry.

The existing specialized reefer fleet is old and few new ships are being built or commissioned. At the same time, there is an increasing demand of shipping perishables to St. Petersburg, inciting the strengthening of existing ships to meet market demands. The methodology used in this report is a compilation of selective literature research (primarily providing qualitative, secondary data) and a comparative study in which the secondary data is applied on the reefer classes Crown and Family.

While other classification societies are mentioned, this report focuses on Lloyd’s Register and the ice classes 1D and 1C, suitable for very light and light ice conditions and sailing in convoy with icebreaker assistance. Although ice class 1C is designated for tougher ice conditions than 1D, they share many strengthening requirements. Most substantially, the requirements for 1C concerning the forward region and steering arrangements, stipulated by the Swedish Maritime Administration (Swedish: Sjöfartsverket), are also applicable to 1D. The main differences between these classes originate from the expanse of waterline and structural strengthening in the ice belt, propeller and screw shaft requirements and lastly, the requirements concerning machinery layout and engine output.

The results comprise of estimations regarding minimum engine output, ice belt cost, thickness and spread, bow strengthening and a commentary on the remaining requirements that have been omitted in the analysis. Conclusively, depending on the shipping company’s predefined operational and financial goals, the initial choice of class notation should be evident based on the information presented in this report. If, for example, the Crown class is intended for shipping perishable goods to St. Petersburg all year round, the incentives for converting the ship to ice class 1C are strong, due to a higher reliability in ETA. The effects of added weight and higher expenses could however advocate ice class 1D. Similarly, should the Family class only sail sporadically to St. Petersburg, it could be more financially sensible to convert the ship to ice class 1D.

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