Doesn't seem likely. He'd have to;
-know where the mecanism controlling the Gate of Justice is located
-access it while he's standing on an isolated bridge in the middle of the seaWhatever he does, I hope it's more of a stealth mission than anything overly physical, him saving the day by kicking the bad guys asses all by himself wouldn't feel right at all.
He could simply deduce that in order for the escort ship to leave Enis Lobby through the Gates of Justice there would have to be away to open the Gates from the Bridge of Hesitation. So the mechanism could be inside one of the towers that that they are fighting on.
The whirling currents may not end up being the only downfall of the BC, Ussop's Kabuto could take out all of the ships sails and masts. Thus leaving the ships completely helpless to the currents.