We're looking at several routings from ORD-STT, and need to connect to a Tortola-bound ferry.

The best price (using AA) arrives STT via CLT at 3:15.

My best interpretation of the ferry schedules (www.roadtownfastferry.com) shows the last departure CA to RT at 4:15

Is there a later ferry, or is there good confidence of making the connection?

There is a routing through MIA which arrives earlier, but it's a few $100's more.