Our crew had maintained a good training record so we were cleared for a cross-country trip to Montgomery, Alabama on a day when the weather was questionable. We were contacted in route and ordered to return to base, (Gulfport) immediately as the weather was deteriorating rapidly. The landing approach from the north brought us in east of New Orleans over the Bay of St. Louis. From there we would follow the Gulf coastline east to the base at Gulfport. The broken layer of clouds were very low but the water and ground were still visible. Our navigator and I closed shop and moved to the radio room for landing. However, the landing did not take place. After a period of time I went to the flight deck to find out what was going on. By this time darkness had set in. The pilot had tried a radio beam let down but the beam split and it didn't work. Our two pilots had argued about the procedure and were not talking to each other. It didn't take me long to break the silence. We were lost and had been for about an hour. Our navigator and I returned to the nose and he proceeded to get a fix on our position which was northwest of New Orleans. We took a heading for New Orleans and the city lights piercing the solid lower cloud layer was a welcome site. We let down and flew the coast light line to the base and made a routine landing. The B-17 had just stopped rolling on the runway when a jeep pulled up and took the pilot and navigator to operation headquarters for a briefing. I guess they caught hell. A three state search alert for a possible downed military aircraft had been initiated.