The Gaza flotilla and the maritime blockade of Gaza. Documentation
A maritime blockade is in effect off the coast of Gaza. It has been imposed, as Israel is currently in a state of armed conflict with the Hamas regime that controls Gaza. (1)
Helsinki Principles on the Law of Maritime Neutrality
3. Hostilities on the High Seas (2)
3.1 The Conduct of Hostilities
In conducting hostilities on the high seas, the parties to the conflict must have due regard to the exercise of the freedoms of the high seas by neutral States. In particular, neutral shipping and fishing activities may be limited pursuant to these Principles, but in no case completely excluded.
3.2 Areas of naval hostilities
Neutral ships should be aware of the risk and peril of operating in areas where active naval hostilities take place. Belligerents engaged in naval hostilities must, however, take reasonable precautions including appropriate warnings, if circumstances permit, to avoid damage to neutral ships.
3.3 Special Zones
Subject to Principle 5.2.9 and without prejudice to the rights of commanders in the zone of immediate naval operations, the establishment by a belligerent of special zones does not confer upon that belligerent rights in relation to neutral shipping which it would not otherwise possess. In particular, the establishment of a special zone cannot confer upon a belligerent the right to attack neutral shipping merely on account of its presence in the zone. However, a belligerent may, as an exceptional measure, declare zones where neutral shipping would be particularly exposed to risks caused by the hostilities. The extent, location and duration must be made public and may not go beyond what is required by military necessity, regard being paid to the principle of proportionality. Due regard shall also be given to the rights of all States to legitimate uses of the seas. Where such a zone significantly impedes free and safe access to the ports of a neutral State and the use of normal navigation routes, measures to facilitate safe passage shall be taken. ...
5.2 Belligerent control over neutral shipping
5.2.1 Visit and search
As an exception to Principle 5.1.2. paragraph 1 and in accordance with Principle 1.3 (2nd sentence), belligerent warships have a right to visit and search vis-├á-vis neutral commercial ships in order to ascertain the character and destination of their cargo. If a ship tries to evade this control or offers resistance, measures of coercion necessary to exercise this right are permissible. This includes the right to divert a ship where visit and search at the place where the ship is encountered are not practical.
5.2.2 Seizure and condemnation
Cargo constituting contraband and a ship carrying such cargo may be seized by a belligerent, brought before a prize court and condemned. Confiscation without a prize court decision is prohibited.
Contraband are goods ultimately destined to the enemy of a belligerent which are designed for the use of war fighting and other goods useful for the war effort of the enemy. ...
Blockade, i.e. the interdiction of all or certain maritime traffic coming from or going to a port or coast of a belligerent, is a legitimate method of naval warfare. In order to be valid, the blockade must be declared, notified to belligerent and neutral States, effective and applied impartially to ships of all States. A blockade may not bar access to neutral ports or coasts. Neutral vessels believed on reasonable and probable grounds to be breaching a blockade may be stopped and captured. If they, after prior warning, clearly resist capture, they may be attacked.
Is Israel´s Blockade of Gaza Legal?
Pro-Israel front group Reuters (ahem) asks the timely question: Q&A: Is Israel´s naval blockade of Gaza legal? (3)
The short answers:
Yes, Israel´s blockade is legal under international law.
Yes, Israel has the legal right to stop ships in international waters.
Yes, Israel has the legal right to use force when stopping ships.
And no, this was not "piracy" by any legal definition.
The applicable legally recognized document is titled: San Remo Manual on International Law Applicable to Armed Conflicts at Sea
10. Konvention von Havanna ├╝ber maritime Neutralit├Ąt vom 20.02.1928
SECTION I. FREEDOM OF COMMERCE IN TIME OF WAR (4)
Article 1. The following rules shall govern commerce of war:
 Warships of the belligerents have the right to stop and visit on the high seas and in territorial waters that are not neutral any merchant ship with the object of ascertaining its character and nationality and of verifying whether it conveys cargo prohibited by international law or has committed any violation of blockade. If the merchant ship does not heed the signal to stop, it may be pursued by the warship and stopped by force; outside of such a case the ship cannot be attacked unless, after being hailed, it fails to observe the instructions given it. The ship shall not be rendered incapable of navigation before the crew and passengers have been placed in safety. ..
Art. 2. Both the detention of the vessel and its crew for violation of neutrality shall be made in accordance with the procedure which best suits the state effecting it and at the expense of the transgressing ship. Said state, except in the case of grave fault on its Part, is not responsible for damages which the vessel may suffer.
June 1 / June 8, 2010
(1) The Gaza flotilla and the maritime blockade of Gaza. Israel Ministry of Foreign Affairs, May 31, 2010
(2) Helsinki Principles on the Law of Maritime Neutrality. Viadrina International Law Project. Ein Projekt des Lehrstuhls f├╝r ├ľffentliches Recht insb. V├Âlkerrecht, Europarecht sowie ausl├Ąndisches Verfassungsrecht. Europa-Universit├Ąt Viadrina, Frankfurt (Oder), 2002
Europa-Universit├Ąt Viadrina, Frankfurt (Oder)
(3) San Remo Manual on International Law Applicable to Armed Conflicts at Sea,
International Humanitarian Law - Treaties & Documents, ICRC, 12 June 1994
Is Israel´s Blockade of Gaza Legal? Little Green Footballs, June 8, 2010
(4) Konvention von Havanna ├╝ber maritime Neutralit├Ąt vom 20.02.1928. Convention on Maritime Neutrality. Havana, 20 February 1928. Archiv des humanit├Ąren V├Âlkerrechts in bewaffneten Konflikten. Hrsg. Dr. Norbert B. Wagner,
2. Auflage Br├╝hl/Wesseling, S. 66 ff.