Demonstrations and local tests of several maritime autonomous surface ships (MASS) have recently been carried out. From a technological standpoint, MASS are becoming able to handle actual operations in certain sea areas. Since 2017, the MSC (Maritime Safety Committee) of the IMO (International Maritime Organization) has been discussing legal problems with the Regulations for Preventing Collisions at Sea (COLREGs) with regard to MASS operation. The purpose of this paper is to clarify the rules from the perspective of seafarers, who need to interpret COLREGs when dealing with MASS in ship handling situations on the sea, and also to discuss possible required amendments to COLREGs. This paper attempts to clarify the extent of current interpretations while also taking into account the answers to questionnaires received from 130 pilots, ship captains and navigation officers concerning COLREGs for MASS operation. Given the four common principles of COLREGs, it is considered whether the principles need to be changed with the introduction of MASS from the viewpoint of seafarers.

As fundamental research of the operation of autonomous ships on the monitoring screen on shore, this paper focused on the differences in collision avoidance judgments based on various information sources, specifically via radar and via visual confirmation. Experiments were carried out using a ship-handling simulator with 14 seafarer trainees who had acquired the same level of maritime knowledge but had no actual experience at sea. Two experiments were carried out: a simple situation with one target ship appearing, and a complex situation where several targets appeared. The judgments in the complex situation showed that radar decision timing was quicker than visual decision timing. On the other hand, the simple situation showed no difference in course alteration and timing. Further results indicated that evaluation of the involved ships in the situation and the back ground of judgments varied depending on information sources. It is suggested that evaluation of the involved ships and the back ground of judgments may lead to differences in collision avoidance judgments. 本研究では，画面上に表示された情報による遠隔操船を考えるための基礎的研究として，操船シミュレー タを用い，目視情報のみを使用し衝突回避判断を行う実験と，計器情報(レーダー)のみを使用し衝突回避 判断を行う実験を，出現する隻数の異なる2種類の交通流で実施し，情報源の違いによる衝突回避判断に関 して検討を行った．実験参加者は，知識はあるが実航海での経験がない14名であった．衝突回避判断および 衝突回避判断に関わる事項を調査分析した．その結果，他船が一隻の状況では衝突回避判断に差がないが， 他船が複数隻存在する状況では，計器情報の方が早めに衝突回避を行うことが示された．このことは，衝突 回避判断に関わる事項( 「関心を抱く船」 ， 「衝突回避判断の背景」 )において，情報源間で差異が生じている ためと考えられた． (キーワード：情報源，衝突回避，レーダー，判断，遠隔操船)1 受付：2016年7月18日 受理：2017年10月24日

No abstract

Campaigns for preventing marine casualty in restricted visibility are carried out every year, but these type of accidents to continue occur. Awareness campaigns suggest using radar suitably, observing the conduct of vessels in restricted visibility, among other precautions. However, other studies have pointed out that some navigators improperly understood how to apply rule in restricted visibility and how to use vector modes on the radar screen.When taking these situations into account, this study investigates how navigators are applying rule in restricted visibility and their understanding of vector mode. The study was conducted by questionnaires, and the results suggest the following: (1) Many navigators confuse conduct of vessels in sight of one another and conduct of vessels in restricted visibility.(2) Some navigators understanding of vector mode is dubious. In the final part of paper, measures for preventing marine casualties are discussed.