Am I paddling a canoe or a kayak?
The right questions are: Are you canoeing or kayaking? How many blades does your paddle have?
Canoeing uses a single-bladed paddle. Kayaking uses a double-bladed paddle. Tongue-in-cheek, some paddlers will tell you, "If you're paddling a canoe with a double blade, then it's not a canoe, it's a kayak."
Where does my boat fit?
Each of the boat specifications for USCA racing classes is distinct. The following three links are works in progress. They each provide a guide by manufacturer and boat model indicating which class the model's specs appears to fit (or which boat you may need to buy, beg, or borrow to fit a particular USCA racing class).
A Guide to USCA Canoe Specs
A Guide to USCA Kayak Specs
A Guide to USCA Paddleboard Specs
There is a bewildering array of canoe, kayak, (and paddleboard) designs. These guides make it easier to understand where your boat fits into the USCA racing class scheme. These guides are under construction. They answer some but not all questions at this point. They will expand over the next months.