London, August 19. The master of the Japanese-registered fishing vessel Musashi Maru (4.3 gt) suffered serious injury when his vessel was in collision with the chemical tanker Ryoka Maru (689 gt). Japanese Coast Guard officials are questioning crewmen from both vessels on suspicion of negligence. On July 14 Ryoka Maru had collided with the dredger Horai Maru, resulting in the dredger sinking.