The bad news is the sailors must still unlock the doors to heads in the first place. At home, we take for granted that if we need to use a toilet, we simply open the door and take care of business. When you have to unlock a door, even with only three digits, you must anticipate and prepare.
The worse news is the head to my son's berthing has been out of order more than 24 hours. He and his shipmates must continue their daily search for a john they can use. If you have ever needed to "go" while in public and every store or restaurant had signs posted that declared Restrooms for employees only or Restrooms are for our paying customers only then, you know the indignity and frustration our sailors at sea must endure.
Better news is a reporter from The Virginian Times has started interviewing him for a possible story.
Please visit the website that's not yet a Google trend, but is fast growing in popularity among searches and is being linked to other sites. There I have more details about the logic behind the locks.