Impact of Port Shallowness (Clearance under the Ship’s Keel) on Shipping Safety, Energy Consumption and Sustainability of Green Ports

Abstract

In a majority of ports, a ship’s speed is limited for reasons of navigational safety. At the same time, captains and port pilots choose the speed of the ship, but it cannot be higher than the speed allowed in the port. Therefore, the speed of the ship also depends on the experience of the masters and harbor pilots and the sailing conditions in specific situations. Choosing the optimal speed of the ship in the port, considering the hydrodynamic effect of shallow water and the controllability of the ship, can help reduce fuel consumption and ship emissions, which is important for the development of a sustainable port. In all cases, the safety of the shipping is the highest priority. The main objectives of this article are determining the optimal speed of ships in ports with low clearance under a ship’s hull, ensuring navigational safety, reducing fuel consumption and emissions, and creating a sustainable port. This article presents the methodology for calculating the optimal ship speed as the minimum controllable speed, fuel consumption and emission reduction, as well as its implications for sustainable and green maritime transport and port development. The methodology presented has been tested on real ships and using a calibrated simulator, navigating through port channels and port water’s restricted conditions.

Dependence of Ships Turning at Port Turning Basins on Clearance under the Ship’s Keel

“…In order to evaluate the controllability of the ship using tugboats or ship steering devices (thrusters), the methods of calculating the turning elements and the trajectory of the ship in shallow depth were used [35,48]. When calculating the ship's energy (fuel) consumption, the power of the tugboat engines or the ship's propulsion mechanisms was calculated, depending on the traction force created by the tugboats or ship's propulsion devices, and the number of emissions, according to the amount and quality of the fuel used (diesel or LNG), the actual ship's propulsion or the power and working time of the tugboat engine when turning the ship [39,49]. To evaluate the accuracy of the calculations and experimental results, the Based on the presented principal methodology (Figure 3), a theoretical model of ship turning with the help of ship pushers or tugboats was created, and experiments were carried out with real ships and with the help of a calibrated simulator; finally, the theoretical model was improved on the basis of real ships and calibrated simulator experiment results [42,43].…”

“…The has been insufficient study of such operations, not only from the point of view of energy (fuel) consumption and generated emissions but also from the point of view of the total cost of the ship itself. If only the main ship control devices (ship rudders and propellers) and additional ship control devices such as thrusters are used with the port tugboats [39,40], it does not allow optimizing the process of turning ships in ports.…”

“…where X in , Y in and M in are the inertia forces and the moment; X k , Y k and M k are the forces and moment created by the ship's hull, which can be calculated by using the methodology stated in [40]; X β , Y β and M β are the ship's hull as the acting "wing"-related forces and the moment, which can be calculated using the methodology stated in [27]; X P , Y P and M P are the forces and the moment created by the ship's rudder or other steering equipment [40]; X N , Y N and M N are forces and the moments created by thrusters [40]; X a , Y a and M a are aerodynamic forces and the moment, which can be calculated using the methodology stated in [40]; X c , Y c and M c are forces and the moment created by the current, which can be calculated using the methodology stated in [40]; X b , Y b and M b are the forces and the moment created by waves, which can be calculated using the methodology stated in [40] (in port conditions this parameter is insignificant and often not applicable); X sh , Y sh and M sh are the forces and the moment created by the shallow water effect [39,40] (in port conditions, this parameter is very important, especially when the ratio of the ship's draft to the depth of the turning basin is greater than 0.9); X T , Y T and M T are the forces and the moment created by ship's propeller (propellers), which can be calculated using the methodology stated in [38,40] and X tug , Y tug and M tug are the forces and moment created by tugs. Additional forces and moments can be created by anchor or mooring ropes or other factors.…”