Here is a link to a post which describes what's in the Navy's deck logs, where they're located, and how to access them:
I found my dad's naval deck logs at Fold3. Our local library subscribes so I could get them through the library. Otherwise you have to be a paid subscriber. They were a great find! They gave a latitude and longitude at three different times of the day. You can plot those on Google Earth and follow where the ship was.