Under regulations prescribed by the Secretary, an enlisted member may be detained in the Coast Guard beyond the term of his enlistment:

((1)) until the first arrival of the vessel on which he is serving at its permanent station, or at a port in a State of the United States or in the District of Columbia; or

((2)) if attached to a shore station beyond the continental limits of the United States or in Alaska, until his first arrival at a port in any State of the United States or in the District of Columbia where his reenlistment or discharge may be effected, or until he can be discharged or reenlisted at his station beyond the continental limits of the United States or in Alaska, whichever is earlier, but in no event to exceed three months; or

((3)) during a period of war or national emergency as proclaimed by the President, and, in the interest of national defense, for a period not to exceed six months after the end of the war or the termination of the emergency; or

((4)) for a period of not exceeding thirty days in other cases whether or not specifically covered by this section, when essential to the public interests, and the determination that such detention is essential to the public interests, made in accordance with regulations prescribed by the Secretary, shall be final and conclusive.