This study quantitatively investigated the increase of ballasting time through simulations when installing UV type BWMS to existing vessels. The actual pressure loss resulting from installing flow control valves at the front of the BWMS was not taken into account quantitatively in this study due to the lack of relevant information and documents. It was found that the increased ballasting time was about 20.8% based on the calculation results.
As a result of the shipboard test, the increase of ballasting time before and after UV BWMS installation on board was about 22.2% which is almost similar to the above calculation result.
In addition, as a result of the land-based test and the shipboard test, the average flow loss of land-based test due to the installation of UV BWMS and the filter was 18.56% and the average flow loss of shipboard test due to the installation of the filter was 13.9%.
The simulation of ballasting time as per the different pipe material roughness was undertaken for 55K LPG Carrier, 325K VLOC and 23,000 TEU Container vessel. As a result of this simulation, it was found that the ballasting time of 55K LPG Carrier was decreased at about 1.9% in case where plastic pipes were used instead of steel pipes.
It was also found that the ballasting time of 325K VLOC and 23,000 TEU container vessel was decreased 0.73% and 11.13% respectively by using plastic pipes instead of steel pipes. The decrease rate of ballasting time in the case of 23,000 TEU Container vessel was remarkably increased due to the large increase of pipe length compared to 55K LPG Carrier in spite of the small increase of pipe size from 300A to 350A.
Therefore, it is advisable for concerned parties to minimize ships’ operation losses from the increase of ballasting time by considering the plenty capacity of the actual ballast pumps on board and the actual pressure loss of the UV BWMS when selecting a UV BWMS. Additionally, larger capacity of BWMS, larger size of pipes and inside coating of pipe are recommended to minimize the increase of ballasting time after installation of BWMS.