singapore five crew members dominican-registered dredger miss collision indonesian-registered tanker singapore territorial water wednesday singapore marine port authority mpa say miss include four chinese nationals one malaysian mpa say seven chinese nationals rescue say dredger capsize currently partially submerge tanker report damage starboard mpa say singapore authorities conduct search rescue operations singapore navy deploy three patrol craft singapore air force also deploy helicopter conduct aerial search mpa say say disruption ship traffic singapore strait five crew miss dredger collide tanker singapore