Fallout 3 (intelligence bobble head) Rivet City ??? (Xbox 360)?

Iv heard you can get to Rivet City Lab for the Intelligence bobble head before the main quest actually takes you there ?? Im at the rusty old ship which i believe IS Rivet City but cant find a way on as the gang plank isnt extended.. how do i get onto the ship and to the lab without waiting for my Dad to take me there ??