## 4 Results
### Investigating the Causes of Delays in the Context of Port Regulations  
As demonstrated by statistical analysis, traffic intensity is not the only factor impacting the delays of ships on the studied fairway. There is also not too high correlation between intensity and the occurrence or duration of delays. Subsequent research has focused on determining the extent to which Port Regulations [36] contribute to ship delays. In the study, the total delay time of ships during one observation period (12 h) was collected, as well as the number of ships that were delayed during that period of time. Then, it was determined which of the regulations had a direct impact on the delay of a given vessel. For the purpose of the research on Port Regulations, seven main causes of ship delays were identified:  
1. [wide=0.5 cm]
2. [wide=0.5 cm]
3. [wide  
Ships with a draft exceeding 9.0 m, south of the northern tip of Mielin Island, are allowed to move with visibility of not less than 2.0 Mm, and from the Brama Torowa No 1 only during the daytime. The movement of tankers with dangerous cargo can be carried out with visibility of not less than 1 Mm. In addition, another factor that determines safe passage of the ship and can generate delays is the water level in the port. With the water level below the established average water levels, the allowable ship draft at the berth decreases by a correction factor equal to the current difference in water level expressed in centimeters. The established average water level for the port of Szczecin is currently 515 cm and for Police, 507 cm [36]. 4. Ferries at Swinoujscie. In this study, a separate category of delays caused by ferries calling at the port of Swinoujscie has been identified. The exceeding of the technical parameters between ferries and ships from the ports of Szczecin and Police (i.e., total length and/or width or permissible drafts) has been treated as an identical cause of delays, referred to as \"ferries\" in the study. This approach was necessary due to the inability to conduct research in the port of Swinoujscie and the impossibility of detailed analyses of the vessels operating there. 5. Due to exceeded L--length overall. In accordance with Article 52(2) of the Port Regulations [36], from the pair of buoys '15-16' of the approach channel to Swinoujscie to the Orli Przesmyk (63.0 km of the channel), two-way traffic of vessels with a draft of up to 7.40 m is allowed, provided that the sum of the overall lengths of the passing vessels does not exceed 320 m. However, on the stretch from the pair of buoys '15-16' to buoy 'D', there is a limitation on the sum of the lengths of passing vessels (Article 52(3)). On this section of the channel, vessels with a draft of up to 9.50 m may be passed by vessels with a draft of up to 6.10 m, provided that the sum of the overall lengths of the passing vessels does not exceed 280 m.  
On the stretch from the northern cape of the Kosa Peninsula (3.7 km) to the Karsibor bend (10.5 km), vessels with a draft above 7.40 m, provided their overall length does not exceed 160 m, may be passed by vessels with an overall length of up to 120 m and a draft of up to 6.10 m. Vessels with a draft above 7.40 m and an overall length exceeding 160 m may be passed by vessels with an overall length of up to 120 m and a draft of up to 4.0 m. In both cases, the total length of the passing vessels cannot exceed 280 m.  
From the Karsibor bend (10.5 km) to the northern cape of the Chelminek Island (35.0 km), from the Zukawy ponds to the Krepa Dolna pond, and from the Radun Gorna pond to the Infski Nurt, vessels with a draft of up to 9.15 m may be passed by vessels with a draft of up to 7.40 m, provided that the sum of the overall lengths of the passing vessels does not exceed 320 m.  
The Port Regulations [36] significantly limit the allowable overall length of vessels in the Mielno Canal.