The Hammerhead has 6 turrets, all manned. The confusion on the turrets came from a fairly last minute change to convert two of them from unmanned to all of them being manned hence how there were combinations of 6 and 6+2 kicking around. Development is a very real-time process, and here you get to see it - warts and all. We talk amongst ourselves and tweak the designs a lot even during the design process - as you've seen from our other features, a great deal of iteration occurs even in the concept phase and continues beyond! The mass value given was from the original design brief for the ship and wasn't updated in time for the release with the new calculations as detailed in the recent Shipyard posts. We will be updating the dimensions and mass values on the ship stats page soon, but as the ship is in active production it may change in the future.