Is this a real combo, or a "nombo"? In general, Scheme lets you keep your Durations in play for four turns instead of two, making it even more likely that you'll find another Scheme to keep the duration going.
In this game, with just a single Scheme and Merchant Ship, I get a Merchant Ship in play on Turn 5, and with the exception of Turn 13, the MS would have never gone out of play until Turn 17 at the earliest. The Scheme picks itself up until the Duration is ready to leave play, whereupon the Duration goes back in for two more turns, allowing you two chances to draw back your Scheme.
It seems like with Wharf this chain would be even easier to continue, since you are cycling your deck more quickly.