He impressed the Iron manager Brian Laws enough to be taken on as a non-contract player in September 2004. He was 19 at the time, and more commonly known by his nickname Shabba (after the singer Shabba Ranks).
Things started well for the youngster when he came off the bench with 14 minutes to go for his first appearance in claret and blue during a League Two game at Bury.
Rankine, a substitute for Paul Hayes, tapped in from close range in the final minute of normal time after United's skipper Andy Crosby had headed on a free-kick by Peter Beagrie to seal a 1-0 win.
It was a fairytale debut for Rankine, but that was as good as it got at Iron for him. He did not find the net again that season, and despite 23 further appearances - mostly off the bench - his only other meaningful statistic was a booking in a game against Notts County.
United finished that season second in League Two to seal automatic promotion to League One, but it was a bittersweet success for Rankine who was released that summer. He went on to join Alfreton then Rushen and Diamonds.