Navicert

A Navicert, also spelled navi-cert, was a document issued by the British government during both World War I and World War II to neutral shipping, primarily American, to permit the carriage of non-contraband goods through the Allied blockade of enemy-controlled or occupied territory.

The Navicert system was introduced as a means to exert economic pressure on enemy powers without completely severing trade relations with neutral countries. Ship owners could apply for a Navicert before loading cargo destined for a neutral port. If the cargo and its ultimate destination were deemed acceptable by British authorities (i.e., not ultimately bound for the enemy), a Navicert would be issued. Ships carrying a Navicert were less likely to be delayed or seized by the Allied navies.

This system helped streamline the blockade and reduce conflicts with neutral nations, as it provided a mechanism for pre-approval and minimized the need for extensive searches and seizures at sea. Refusal to participate in the Navicert system, however, significantly increased the risk of a vessel being intercepted and its cargo confiscated. Therefore, it effectively incentivized neutral shippers to comply with Allied regulations.