According to http://www.shipbuildinghistory.com/history/shipyards/4emergency/wwtwo/kcalifornia.htm, the SS JERICHO VICTORY was built by the California Shipbuilding Corporation in Los Angeles. Her keel was laid 15 October 1944, she was launched 6 December 1944, and she was completed and delivered for service on 13 January 1945, 52 days after keel-laying. Apparently your father was part of her first crew.
From all indications she had a rather uneventful wartime and post-war career and probably was laid up (mothballed) for a time in the reserve fleet. She was owned by the U.S. War Shipping Administration until 1961, when she was sold to Terrace Navigation Company of New York and renamed THUNDERBIRD. Then she was sold again in 1970 to Service Shipping S.A. of Panama and sailed briefly under the Panamanian flag with the name NORTH RIVER. She was scrapped in Taiwan in 1971. See http://www.mariners-l.co.uk/vicshipsH.html and scroll down.
We don't know, of course, what event was related to the "lost at sea" incident that your uncle related to your brother. One guess is that it involved a shipwreck or other catastrophe but there is nothing in the sketchy history of the ship above to suggest anything out of the ordinary happened to the JERICHO VICTORY during her career. Or perhaps more likely, "lost at sea" may refer to being swept overboard which would certainly be a catastrophe for a sailor, but such an incident would probably not be part of the broad history of the ship.
Here is a suggestion for you to explore. Apparently you already have your father's complete service record, since you have the dates during which he sailed in the JERICHO VICTORY. You may be able to obtain additional information about his voyages by contacting the National Archives. The Archives has custody of a wide range of records relating to warships, merchant ships on which Armed Guard units served, and other Navy units for the period from World War II through Vietnam, with a heavy concentration in World War II records. These records include Armed Guard logbooks and reports, action reports, vessel movement report cards, and records of individual convoys. You would probably be particularly interested in the Armed Guard logbooks and reports, which would list the Armed Guard crew on the ship in question, and detail any significant events during a voyage. Certainly losing a man overboard would be a significant event, if that's what happened.
To learn more about the scope of these materials and to request records for a given ship, write to the following address:
Modern Military Records Unit (NWCTM)
National Archives and Records Administration
8601 Adelphi Road
College Park, MD 20740-6001
In your letter, include the names of the ship, the date/time period of interest; your full name, address, and telephone number; and as much other detail as possible about the information you would like to obtain. Due to the volume of requests received and the time needed to identify all appropriate records, Archives staff requests that you limit your request to five items per each letter. Allow approximately 10 – 12 weeks from the initial inquiry to receipt of the records.
A charge will be imposed for reproduction/mailing of the records, however do not send any cash/check/charge card information with your initial inquiry. Archives staff will review your request and mail to you an estimate of the cost and payment information. Follow the directions contained in that letter to order the desired records.
I hope this information is useful.
Ron Carlson, Webmaster
Armed Guard website www.armed-guard.com