[Sidenote: Lawful and Unlawful Practices of Sea Warfare.] § 174. As regards means of sea warfare, just as regards means of land warfare, it must be emphasised that not every practice capable of injuring the enemy in offence and defence is lawful. Although no regulations regarding the laws of war on sea have as yet been enacted by a general law-making treaty as a pendant to the Hague Regulations, there are treaties concerning special points--such as submarine mines, bombardment by naval forces, and others--and customary rules of International Law in existence which regulate the matter. Be that as it may, the rules concerning sea warfare are in many points identical with, but in many respects differ from, the rules in force regarding warfare on land. Therefore, the means of sea warfare must be discussed separately in the following sections. But blockade and capture of vessels carrying contraband and rendering unneutral service to the enemy, although they are means of warfare against an enemy, are of such importance as regards neutral trade that they will be discussed below in Part III. §§ 368-413. [Sidenote: Objects of the Means of Sea Warfare.] § 175. Whereas the objects against which means of land warfare may be directed are innumerable, the number of the objects against which means of sea warfare are directed is very limited, comprising six objects only. The chief object is enemy vessels, whether public or private; the next, enemy individuals, with distinction between those taking part in fighting and others; the third, enemy goods on enemy vessels; the fourth, the enemy coast; the fifth and sixth, neutral vessels attempting to break blockade, carrying contraband, or rendering unneutral service to the enemy. [Sidenote: Development of International Law regarding Private Property on Sea.]