In Assassin's Creed 3, you have the option of sending out convoys loaded with goods for sale.
I'm lead to believe that this should be your primary means of income as you roam the frontier and kill defenseless animals for the sake of profit. I've seen this question about what to do when a convoy is under attack, but it doesn't indicate what to do after the fact.
Unfortunately, I was unable to make it to my convoy in time to prevent the attack, and now my convoy is completely lost. A look at my ledger shows that I currently have no convoys available. This has put me in a bit of a financial bind.
How can I get more convoys if, and when, I lose the one(s) I currently have?