Art. 10. If the operations of the blockading power, or of the naval authorities acting in its name, do not tally with the particulars, which, in accordance with Article 9 (1) and (2), must be inserted in the declaration of blockade, the declaration is void, and a new declaration is necessary in order to make the blockade operative.
Art. 11. A declaration of blockade is notified: (1) to neutral powers, by the blockading power by means of a communication addressed to the governments direct, or to their representatives accredited to it; (2) to the local authorities, by the officer commanding the blockading force. The local authorities will, in turn, inform the foreign consular officers at the port or on the coastline under blockade as soon as possible.
Art. 12. The rules as to declaration and notification of blockade apply to cases where the limits of a blockade are extended, or where a blockade is re-established after having been raised.
Art. 13. The voluntary raising of a blockade, as also any restriction in the limits of a blockade, must be notified in the manner prescribed by Article 11.
Art. 14. The liability of a neutral vessel to capture for breach of blockade is contingent on her knowledge, actual or presumptive, of the blockade.
Art. 15. Failing proof to the contrary, knowledge of the blockade is presumed if the vessel left a neutral port subsequently to the notification of the blockade to the power to which such port belongs, provided that such notification was made in sufficient time.
Art. 16. If a vessel approaching a blockaded port has no knowledge, actual or presumptive, of the blockade, the notification must be made to the vessel itself by an officer of one of the ships of the blockading force. This notification should be entered in the vessel’s logbook, and must state the day and hour, and the geographical position of the vessel at the time. If through the negligence of the officer commanding the blockading force no declaration of blockade has been notified to the local authorities, or if in the declaration, as notified, no period has been mentioned within which neutral vessels may come out, a neutral vessel coming out of the blockaded port must be allowed to pass free.
Art. 17. Neutral vessels may not be captured for breach of blockade except within the area of operations of the warships detailed to render the blockade effective.
Art. 18. The blockading forces must not bar access to neutral ports or coasts.