USS Fitzgerald Collision: NTSB Investigation Report Highlights Navy Failures,

Ok, I finished reading this and am underwhelmed but there is one thing that really bothers me that I was really hoping to see in this report.

According to the Navy investigation report “ A sailor had to call Destroyer Squadron 15 on a personal cell phone at about 2:15 a.m. to notify them of the catastrophe, according to the report.”

Nobody has answered the question as to why all communication, backup communication, and emergency communication gear failed on the USS Fitzgerald after the collision?? Why did they have to wait till they hobbled close to shore to call in the mayday via cell phone?

Or am I missing something?