And give up on the brig

They're relatively fast, sure, but not very maneuverable, not very sturdy, and not very well armed (for its size). They're transports and prison ships, not fighting ships, which you should know if you've ever fought any. They're easy pickings

You'd be better off with a Shnyava...it's fast enough and well-armed enough to let you pick off whatever you can, and run from whatever you can't

And with a couple prize ships captured (especially loaded Spanish merchants), you really start to rake in the cash and can forget about bothering with mere trade.
------------------
-Mekhazzio Sssth'rhee, Magedragon at large