Dear Mr. Mathis,
Thank you for posting your request on History Hub!
We searched the National Archives Catalog and located Central Correspondence Files, 1936 - 1950 in the Records of the U.S. Maritime Commission (Record Group 178) which includes 901-10954 William Thornton (SS) (MCE #1102).
Additionally, we located Official Logbooks of Merchant Vessels, Port of Philadelphia, 1920 - 1980 in the Records of the U.S. Coast Guard (Record Group 26) which includes the file Official Logbook of Merchant Vessel William Thornton; Official Logbooks of Merchant Vessels, 1942 - 1989 in Record Group 26 which includes 4 files for the William Thorton; and Official Merchant Vessel Logbooks, 1942 - 1978 in Record Group 26 which includes logs for the William Thornton in Box 240.
We also located Secret Logs for United States Merchant Vessels, 1942 - 1946 in the Records of Naval Districts and Shore Establishments (Record Group 181) which includes the file William Thornton.
We did not locate any comparable records for any vessel by the name of SS Matsonia during World War II. For more information about these records, please email the reference unit listed in the various Catalog descriptions.
Due to the COVID-19 pandemic and pursuant to guidance received from the Office of Management and Budget (OMB), NARA has adjusted its normal operations to balance the need of completing its mission-critical work while also adhering to the recommended social distancing for the safety of NARA staff. As a result of this re-prioritization of activities, you may experience a delay in receiving an initial acknowledgement as well as a substantive response to your reference request from various NARA units. We apologize for this inconvenience and appreciate your understanding and patience.
We hope this is helpful. Best of luck with your research!