## 7 Conclusions  
This research improved the method to develop the regulatory frame on the competence of RO, focusing on watchkeeping on the navigation bridge under the recognition that remote control and RO are the critical elements for future MASS. It adopted the extended SA model and constructed GBGA model as a tool for developing the regulatory frame. The goal of GBGA model is set as 'keep the same quality of SA for RO as OOW'. Then GBGA model was demonstrated by a case study in which experts were made mini focus group discussions with interviews. The results expressed the trend of ship sense on required information for each Level SA for watchkeeping, and the lack of ship sense and the failure of required information for RO, then additional competence and possible change of regulatory requirements compared to current provisions in the STCW Convention.  
There are some limitations to this research. At first, this research applies one typical case on a remote control system based on the previously conducted projects. It could recognise the trend of the failure of ship sense and required information and additional requirements. Nevertheless, deferent or more detailed outputs can be found if GBGA could be applied to various MASS situations by changing assumptions, including autonomy level and operation area. Second, the case study was made by three experts. All of them are professional officers and veteran instructors, and sufficient and constructive output could be made based on the interview and active discussions. Notwithstanding, the participation of more experts will bring out additional useful comments and suggestions. Third, the measure to retain safety for MASS should take a comprehensive approach. An expert commented that the addition of competence is not enough, and it is necessary to consider the combination of RO's competence and other factors such as bridge manning and technological innovation. He stressed, in particular, the style of watchkeeping might change according to future technology. Lastly, the competence for dealing with an emergency situation, including a fire, pirate, and cyber-attack, is also vital for safety and security. Future research should consider this matter.  
Despite the above limitation, the output of this paper has useful implications. At first, the case study supports that the proposed GBGA method is a valuable tool to develop regulatory requirements for seafarers' competence based on ship awareness. Thus, the method can be utilised as a tool not only for establishing international or national rules of RO in MASS but also for assessing whether regulatory requirements for RO are sufficient for newly introduced MASS. Second, the points that were suggested in the discussion show the whole trend of RO as described in the last paragraph.  
Therefore, future research on the requirements of RO can consider these points. Lastly, the results can be a basement for introducing the combination of competence requirements, the training for officials and innovative technology for MASS.  
Future research on detailed consideration of competence requirements for RO under various cases is expected based on this research.  
Conceptualisation, M.Y., E.S. and M.S.; formal analysis, M.Y. and A.U.; investigation, M.Y.; methodology, M.Y. and M.S.; supervision, M.Y. and E.S.; visualisation, M.Y.; writing--original draft, M.Y.; writing--review and editing, M.Y., E.S., A.U. and M.S. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
The authors declare no conflict of interest.