Great find! Thanks for this. But after reading I wonder how many of these subs can be out there crossing waters of the USA while the whole coast on both sides are monitored full time on irregularities by the US military?
I don't suppose it will be long, if it hasn't happened already, before unmanned drones will be delivering most of the illicit cross-border shipments. You could cheaply build a fleet of them and overwhelm most coastal defenses.