## 5 Conclusions  
The changed SOLAS Convention, forcing shippers to weigh containers before loading seems to be just the beginning of forming new rules applying to container vessels, as there are still many problems to be solved:  
* In the case under consideration, the weight of 4% of the loaded containers was changed by 0.5 t, which was sufficient for one of the most important parameters, the metacentric height, not to meet the requirement. For this reason, it would be advisable to improve and standardize the process of weighing containers before loading. It is also evident that an attempt should be made to minimize the measurement error since even a slight change in the weight of a container can affect stability. * The container weight verification process should be independent of third parties. In addition, to avoid inaccuracies, it should take place just before the container is loaded onto the ship. One way of doing this would be to use a flat scale that first weighs the container with the truck carrying it and then, after the container has been lifted by crane, the truck itself. The resulting container weight seems to be the most reliable, and weighing alone would not affect the loading rate. Figure 3: Probable causes of damage to the hull structure of MSC Napoli. Authors’ elaboration. An update to the loading plan after routine container weighing--the terminals start to weigh containers again on their own, but these data are not always compared to the ones declared. Although the IMO, MCA, and WCS guidance are clear about it, the importance of this practice must be highlighted. No information is available about the distribution of cargo in the container space, which necessitates the estimated center of gravity to be assumed through mathematical calculations. Containers loaded onto a ship are not always placed in the positions specified in the loading plan, and plans are often updated after the ship's departure. Cargo Securing Manuals are in many cases impractical, as the capacity, number of rows, bays, possible stowing configuration, and loading conditions cannot be inserted in a single paper document. The hashing calculations are now often done using a computer. However, there are no general mandatory requirements or performance criteria. Decision support tools in bad weather conditions should be spread onboard ships, making the crew more aware of parametric rolling and whipping effects. Bureau International des Containers, appointed by the IMO, formed two databases, containing technical details for individual containers. Both databases are incomplete, hence, it is not possible to assess all the containers before loading. Such databases should be developed as stack collapses are also connected with structural failures of containers. [PERSON]'s analysis can easily contribute to estimating the effect of individual causes, as well as the elements contributing to these causes, and can rank the importance of their effect on the damage to the ship (in the case in question, human error in loading containers on the MSC Napoli). Despite the implementation of further restrictions and preventive measures, container ships are still prone to accidents. This is why further work needs to be carried out into this matter. This will be the topic of the authors' further works. The aim of the article was to gather all unsolved problems regarding container weight declaration in an attempt to raise awareness and contribute to the implementation of further changes. It also introduces the general methods that can be developed to solve the problems mentioned. The article investigated the problem of the verified gross mass of containers in light of the last IMO amendment, measuring the performance and effectiveness of the regulation. The main conclusions of the research are that there is still space to improve the law and that there is a need to help all concerned parties in terms of adapting to the existing changes. Conceptualization, M.K. ; Methodology, D.L. ; Investigation, W.S. ; Resources, K.B. ; Writing--original draft, M.K.