Vol.25, No.1, 2025, pp. 19–26
https://doi.org/10.69644/ivk-2025-01-0019

This paper assesses the structural integrity of atypical superstructures mounted on the decks of two sister sea-going tankers under extreme load conditions. Namely, each tanker features a pair of deckhouses which are welded onto the existing deck structure girders, exposing them directly to harsh environmental loads. These deckhouses, designed as ‘ad hoc’ solutions resembling land-based structures with similar applications, serve as storage for ballast water treatment systems, added due to insufficient internal technical space within the existing ship structure. Given the lack of fully developed regulations for assessing the structural integrity of novel and atypical ship structures, classification rules typically require a direct structural assessment to ensure their structural integrity. Therefore, this study uses the finite element method to analyse extreme design load scenarios faced by these structures, including seawater loads from waves, wind loads, accelerations due to ship motions, and static loads from the structures’ and internal equipment weights. Besides identifying critical areas, the findings reveal that the initially proposed deckhouse structures failed to meet the criteria for certain scantling arrangements and demonstrate how variations in scantlings affect the overall structural response. Based on these insights, general recommendations for modifying the deckhouse structure are proposed.

Keywords: • thin-walled superstructure • finite element analysis (FEA) • deckhouse • tanker • extreme conditions • environmental loads