# Statistical Analysis of the Weight and Center-of-Gravity Position of an Empty Container Ship
## 2 Materials and Method  
### Materials  
In accordance with the assumed research goal to develop regression formulas for the weight and center of gravity of light container ships ranging from 270 _TEU_ to 3100 _TEU_, data were collected for modern container ships. This data was divided into two sets due to the number of available parameters for individual container ships:  
* one set contains technical and operational parameters and weight light ship for 96 container ships, (the range of technical parameters is provided in Table 2), built in the years 2000-2024; technical parameters and weights light of individual container ships were collected from the Sea-web Ships database [33];
* the other set contains, in addition to technical and operational parameters, accurate weight data for all classes (Table 1), weight light ship and coordinates of the center of gravity position for 13 container ships--the data come from shipyard documentation, calculated during the design and construction of these ships, (the range of technical parameters is provided in Table 3)--Sea-web Ships database does not contain this type of data.  
The number of the first group (Table 2) is not large, but these are all container ships of the same type (functional and structural and with the same equipment for a given range of transported containers) built in the years 2000-2024, the parameters of which are included in the database [33]. The research did not include older container ships, because the models were supposed to be for the newest ones. The number of the second group (Table 3) is a small population, but these are reliable and representative data, because they contain detailed weight parameters developed during the design and construction of these container ships in the shipyard.  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline
**Parameter** & \(L_{oa}\) **[m]** & \(L\) **[m]** & \(B\) **[m]** & \(H\) **[m]** & \(T\) **[m]** & _DWT_ **[t]** & _TEU_ **[-]** & \(V\) **[kn]** \\ \hline Max. & 207.4 & 195.4 & 30.60 & 16.75 & 11.95 & 41,583 & 2506 & 23.7 \\ \hline Min. & 93.5 & 85.0 & 15.85 & 6.40 & 4.90 & 3950 & 270 & 13.5 \\ \hline \end{tabular}
\end{table}
Table 2: Range of basic technical parameters of container ships for the first set (96 container ships).  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline
**Parameter** & \(L_{oa}\) **[m]** & \(L\) **[m]** & \(B\) **[m]** & \(H\) **[m]** & \(T\) **[m]** & _DWT_ **[t]** & _TEU_ **[-]** & \(V\) **[kn]** \\ \hline Max. & 220.0 & 210.2 & 32.25 & 18.7 & 12.1 & 45,000 & 3100 & 22.3 \\ \hline Min. & 123.0 & 113.7 & 15.50 & 9.0 & 6.4 & 6300 & 420 & 13.0 \\ \hline \end{tabular}
\end{table}
Table 3: Range of basic technical parameters of container ships for the second set (13 container ships).  
For two container ships, the results of measurements (after construction and sea trials) of the weight and position of the center of gravity are also available--these data were used to verify the obtained test results.  
The container ships selected for the study were of the same functional and structural type, and each container ship had:  
* a single propeller, one rudder located behind the propeller and one bow tunnel thruster, the hull with a bulbous bow and transom stern,
* an engine room and superstructure at the stern,
* hatch covers on which the containers are stacked,
* unloading cranes (2 or 3 depending on the ship size),
* however, the container ships differed mainly in size: main dimensions, displacement and container capacity.  
A general plan of an example container ship is shown in Figure 3.