## 3 Results
### Bow-Tie Risk Analysis  
We used the highly representative risk factors of ship collision incidents selected by RST and the decision-making group to analyze and discuss the preventive measures, possible consequences, and mitigation measures for each risk factor of ship collision incidents. Finally, the results were applied to BowTieXP to construct a complete bow-tie risk analysis chart for ship collision incidents. The result shows preventive management against ship collision incidents, as well as the mitigation measures after incidents to avoid more severe consequences (Figure 2). Figure 2: Bow-tie risk analysis diagram of ship collision incidents. Seven factors of ship collisions were included, i.e., carelessness, improper operation, unfamiliarity with local navigation regulations, unfamiliarity with ship characteristics, mechanical malfunction, poor sea conditions, and traffic density. Moreover, the preventive measures were as follows:  
* Carelessness  
The preventive measures for carelessness included the elimination of unsuitable crew members and the establishment of basic techniques for preventing collisions and for safety awareness. * Personal improper operation  
The preventive measures for the improper operation of equipment included professional training, pre-employment education, training for crew members, and the set-up of a remote monitoring system. * Unfamiliarity with local navigation regulations  
The preventive measures for unfamiliarity with local navigation regulations included pre-employment education and training, communication with the local country, and establishment of a crew's self-learning attitude. * Unfamiliarity with ship characteristics  
The preventive measures for unfamiliarity with a ship's characteristics included the deployment of experienced crew members, pre-employment education and training, competency assessment, and the establishment of safety awareness. * Mechanical malfunction  
The preventive measures for mechanical malfunction, such as for an abnormality of the main engine, reducer, and steering gear, included regular maintenance, pre-inspection, replacement of old equipment, and the set-up of a remote monitoring system or intelligent navigation warning system. * Poor sea conditions  
The preventive measures for poor sea conditions included the verification of weather forecast data in the sailing plan and the use of intelligent navigation warning systems to adjust the speed and routes in time. * Traffic density  
The preventive measures for traffic density included assigning experienced crew to assist in operating the ship, increasing the crew for a sharp lookout, and setting-up a remote monitoring system or intelligent navigation warning system. The consequences of ship collision, including crew casualties, marine pollution, damage or sinking of the ship and operating losses, etc. The relevant mitigation measures are described as follows:  
* Injured, missing, or dead  
Crews working on the outer deck on duty should wear buoys equipped with signal transmitters, and medical emergency technicians should be on board to rescue injured persons immediately. Moreover, the crew should immediately report to the relevant department for assistance when a person falls into the sea or disappears [6; 7]. * Marine pollution  
The condition of the ship should be checked at once when it collides. If there is a risk of oil pollution, the relevant local department should be notified immediately. The ship or rescue ship should carry out the residual oil extraction procedure, install oil pollution diffusion equipment, and execute leak plugging operations. Furthermore, they should take interception, diffusion, and neutralization measures to avoid serious marine pollution and ecological catastrophes [8]. The coast guard authority shall perform interdiction, collection of evidence, or enforcement referral tasks implemented pursuant to Marine Pollution Control Act in Taiwan, rather than the related procedures according to international convention.