Multiple U.S. and Japanese investigations are under way into how the guided missile destroyer USS Fitzgerald and the much larger ACX Crystal container ship collided in clear weather south of Tokyo Bay in the early hours of June 17.
The service was held at Fleet Activities Yokosuka, the naval base where the USS Fitzgerald is based.
The sailors, aged 19 to 37, were found by divers in flooded sleeping berths a day after the collision tore a huge gash in the side of the Fitzgerald.
The honored U.S. sailors were (top row, left to right): Fire Controlman 2nd Class Carlos Victor Ganzon Sibayan, 23, from Chula Vista, CA; Gunner's Mate Seaman Dakota Kyle Rigsby, 19, from Palmyra, VA; Sonar Technician 3rd Class Ngoc T Truong Huynh, 25, from Oakville, CT; and Yeoman 3rd Class Shingo Alexander Douglass, 25, from San Diego, CA.
Two local men were among the seven Navy sailors killed when the USS Fitzgerald crashed with the Philippine merchant ship ACX Crystal off the coast of Japan. "There was no understanding of what had happened at the moment of impact but there was complete understanding of what needed to be done".
The destroyer has left the Yokosuka base, where it was being investigated by Japanese authorities, for repairs of its damaged bow at an unspecified shipyard in Japan, its owner, Dainichi-Invest Corp., said.
Adm. Scott Swift, commander of the U.S. Pacific Fleet, surveyed the ship's damage and praised its crew for saving it from sinking, the 7th Fleet said.
There have been around 30 ship collisions over the past decade in the area, including a 2013 incident in which six Japanese crew died, according to the Japan Coast Guard.
Rear Admiral Brian Fort has been appointed to lead the U.S. investigation, the navy has said.
Both U.S. and Japanese Coast Guard as well as the U.S. Navy, Philippine government, and the Japan Transport Safety Board are investigating the crash and have refused media requests for comments.