Vice Admiral William S. Sims, Commander, United States Naval Forces Operating in European Waters, to the Office of the Chief of Naval Operations
Operation orders of Force Movements, etc Secret Routes for Vessels.
25 December 1917. ROC
Opnav. Washington 2368
BAL NCT 19ADR
2368. Your 1754. Most of delay occasioned by waiting escort. Regular schedule delayed by special arrangements in connection with U.S. SAN DIEGO and MOUNT VERNON. Similar delays should not occur in future. I urge that General Pershing be instructed to make no reports of ship movements. Five of the last six convoys leaving France have been attacked by submarines. The suspicion is very strong that the submarines obtained advance information of these sailings. The convoy mentioned in your 1764 was not attacked. 00524.
Source Note: Cy, DNA, RG 45, Entry 517B.