§ 180. Whereas in land warfare all sorts of violence against enemy individuals are the chief means, in sea warfare attack and seizure of enemy vessels are the most important means. For together with enemy vessels, a belligerent takes possession of the enemy individuals and enemy goods thereon, so that he can appropriate vessels and goods, as well as detain those enemy individuals who belong to the enemy armed forces as prisoners of war. For this reason, and compared with attack and seizure of enemy vessels, violence against enemy persons and the other means of sea warfare play only a secondary part, although such means are certainly not unimportant. For a weak naval Power can even restrict the operations of her fleet to mere coast defence, and thus totally refrain from directly attacking and seizing enemy vessels.
Attack when legitimate.
§ 181. All enemy men-of-war and other public vessels, which are met by a belligerent's men-of-war on the High Seas or within the territorial waters of either belligerent,[357] may at once be attacked, and the attacked vessel may, of course, defend herself by a counter-attack. Enemy merchantmen may be attacked only if they refuse to submit to visit after having been duly signalled to do so. And no duty exists for an enemy merchantman to submit to visit; on the contrary, she may refuse it, and defend herself against an attack. But only a man-of-war is competent to attack men-of-war as well as merchantmen, provided the war takes place between parties to the Declaration of Paris, so that privateering is prohibited. Any merchantman of a belligerent attacking a public or private vessel of the enemy would be considered and treated as a pirate, and the members of the crew would be liable to be treated as war criminals[358] to the same extent as private individuals committing hostilities in land warfare. However, if attacked by an enemy vessel, a merchantman is competent to deliver a counter-attack and need not discontinue her attack because the vessel which opened hostilities takes to flight, but may pursue and seize her.
[357] But not, of course, in territorial waters of neutral States; see the De Fortuyn (1760), Burrell 175.
[358] See above, § [85], and below, § [254]. Should a merchantman, legitimately—after having been herself attacked—or illegitimately, attack an enemy vessel, and succeed in capturing her, the prize, on condemnation, becomes droits of Admiralty and, therefore, the property of the British Government; see article 39 of the Naval Prize Act, 1864, and article 44 of the Naval Prize Bill introduced in 1911.
It must be specially mentioned that an attack upon enemy vessels on the sea may be made by forces on the shore. For instance, this is done when coast batteries fire upon an enemy man-of-war within reach of their guns. Enemy merchantmen, however, may not be attacked in this way, for they may only be attacked by men-of-war after having been signalled in vain to submit to visit.
Attack how effected.
§ 182. One mode of attack which was in use at the time of sailing ships, namely, boarding and fighting the crew, which can be described as a parallel to assault in land warfare, is no longer used, but if an instance occurred, it would be perfectly lawful. Attack is nowadays effected by cannonade, torpedoes, and, if opportunity arises, by ramming; and nothing forbids an attack on enemy vessels by launching projectiles and explosives from air-vessels, provided the belligerents are not parties to the Declaration—see above, § [114]—which prohibits such attacks. As a rule attacks on merchantmen will be made by cannonade only, as the attacking vessel aims at seizing her on account of her value. But, in case the attacked vessel not only takes to flight, but defends herself by a counter-attack, all modes of attack are lawful against her, just as she herself is justified in applying all modes of attack by way of defence.
As regards attack by torpedoes, article 1 No. 3 of Convention VIII. of the Second Peace Conference enacts that it is forbidden to use torpedoes which do not become harmless if they miss their mark.
Submarine Contact Mines.