ANTOI, Viet Nam — On a remote island off the tip of southern Viet Nam, a Navy lieutenant from Rockland, Me, lives an almost squalid life among Vietnamese who man junks in patrols along the swampy, treacherous delta coastline of the Ca Mau peninsula.

The junks stop and search craft that might be secretly bringing arms and supplies to Communist guerrillas in the area.

In his sea-sprayed New England twang, Lt. Wesley Hoch, barefoot and dressed in a baggy black tunic that is the uniform of the junkmen, sounds peculiarly out of place standing at the door of the structure that is his district headquarters. Before him, out in the harbor beyond the barbed wire, is part of his fleet — a motley collection of junks.