## 1 Introduction
\begin{table}
\begin{tabular}{c c} \hline
**Criterion** & **Requirement** \\ \hline Area (A) under the righting arm curve & A\({}_{0-30^{\circ}}\geq 0.055\) m\(\cdot\)rad \\  & A\({}_{0-40^{\circ}}\geq 0.090\) m\(\cdot\)rad \\  & A\({}_{30-40^{\circ}}\geq 0.030\) m\(\cdot\)rad \\ \hline Righting arm (GZ) & GZ\({}_{\varphi\geq 30^{\circ}}\geq 0.20\) m \\ \hline Angle corresponding to the maximum of the righting arms & \(\varphi_{\text{GZmax}}\geq 25^{\circ}\) \\ \hline Initial metacentric height (GM) & GM \(\geq 0.15\) m \\ \hline The weather criterion, where a and b are surface areas in the figure below, is based on: [17] \\ \hline \end{tabular}
\end{table} 
Table 1: Summary of mandatory stability requirements. Authors’ work is based on [17]. increase sufficiently rapidly (the vessel must be sufficiently 'tough'--it must 'hold' sufficiently firmly its equilibrium position). The greatest value of the righting arm (the greatest ability of the ship to return to the equilibrium position) will not occur if the heel angle is too small [17; 20]. * The criterion of initial metacentric height--metacentric height is a measure of the ship's initial stability at small angles of the heel. When its value is high, the ship is considered stiff and will come rapidly to the equilibrium. If the value is low, the rolling will be gentler, but in the event of failure, the ship may lose stability and capsize [21]. * The weather criterion, taking into account the effect of wind and ship motions. According to the weather criterion, the ship's stability is considered to be sufficient when the conventional wind, under conventional conditions, including wave rolling, does not cause exceeding of the heeling angle of \(50^{\circ}\) immersion of openings considered to be open, and ship capsizing. These requirements are deemed to be met when the ship's heeling angle does not exceed \(50^{\circ}\), the angle of flooding, or the angle of capsizing. Detailed requirements for this criterion are contained in the Rules for the Classification and Construction of Sea-going Ships, Part IV, Chapter 2 \"Stability--Basic Requirements and Criteria\" (point 2.1.2) [17; 20]. In practice, ship-specific stability information is contained in the \"Information on Stability for the Master\" or \"Stability calculation aids\". Meeting all the requirements does not guarantee the total safety of the ship. Therefore, it is very important to avoid unfavourable weather conditions that could cause flooding of the deck, shifting of cargo, or increased roll, and lead to serious accidents such as [PERSON]'s fire due to the stack's collapse [22], heavy weather damage of Svendborg Maersk [23], or CMA CGM G. Washington's and MSC Zoe's container loss [24; 25]. The initial loading plan for a container ship is currently created by the shipowner's representative asshore--a planner, who uses a stability program. A version of the loading plan is sent to the ship and checked by the chief officer, commonly responsible for loading. Since 1 July 2016, according to the amended SOLAS Convention, each container must have its weight verified before loading. The freight forwarder is responsible for the verification. The SOLAS amendments indicate two methods that can be used to determine the weight of a container at the end of its process. One method requires the container to be weighed with its cargo after it has been packed and secured [26; 27]. The other method involves adding the weight of the container and the individual items loaded into it [26; 27]. Weight estimation is not permitted. In both methods, the weighing equipment must fulfil national certification and calibration requirements [26; 27]. Data obtained from [28] show, that despite the mandatory weight measurement regulations introduced by the IMO, containers still weigh more than indicated in the documentation. This leads to an erroneous assessment of stability and weakening of the ship's structure due to significant stresses [17].