(_d_) =Navy.= As a vessel of war can without inconvenience to a foreign state pass through or remain within its maritime jurisdiction, it is customary to accord to the vessel and crew immunity from local jurisdiction and freedom of passage unless withheld for special reason. "Their immunity from local jurisdiction has come to be more absolute than that of the official residence of ambassadors, and probably for the reason that they have the efficient means of resistance which an ambassador has not."[183]
In general the exemption from local jurisdiction which a vessel of war enjoys in a foreign state extends: (1) to acts beginning and ending on board the vessel;[184] (2) to all boats, etc., of the vessel of war in charge of the crew of the vessel and upon its service; (3) to freedom from customs and all such regulations as are not necessary for the safety of the port (it was held in case of the United States frigate _Constitution_, in 1879, that she was not liable to salvage charges;[185] the vessel is therefore liable to quarantine, anchorage, etc., rules which imply no derogation of sovereignty); (4) to all persons on board the vessel whether members of the crew or others. This exemption should not be taken as warranting a general exercise of the right of asylum on board vessels of war. Asylum can be granted as an act of hospitality to a political refugee, who cannot use the vessel as a base for political intrigue. Asylum to common criminals cannot be granted without offense to the foreign state. Such criminals are usually surrendered on request of the local authorities.
A commander cannot pursue deserters on shore or exercise external authority.
Hall sums up the general principle as follows, "The immunities of a vessel of war belong to her as a complete instrument, made up of vessel and crew, and intended to be used by the state for specific purposes; the elements of which she is composed are not capable of separate use for those purposes; they consequently are not exempted from the local jurisdiction."[186]
In case of abuse of exemptions the state in whose waters the foreign ship of war is, can request it to depart; and if its request is not complied with, can use force, though the customary method is to resort to diplomatic channels.