Unnecessary weight makes the boat go slow
Her presence held him back so he couldn’t fully shine.
Also refers to the relation-SHIP from Em’s verse. This girl is the one ruining the relationship, so he is going break up with her (throw her off the boat), and move ahead faster.
To help improve the meaning of these lyrics, visit "Where I'm At" by Lloyd Banks (Ft. Eminem) Lyrics and leave a comment on the lyrics box