Vice Admiral William S. Sims, Commander, United States Naval Forces Operating in European Waters, to Secretary of the Navy Josephus Daniels
CABLEGRAM SENT: September 10, 1917.
To: Secretary of the Navy. Serial No. 504
From: Commander Naval Forces European Waters.
504. Refer Opnav 354. Commander-in-Chief requests me to reply. Admiralty opinion is as follows. On September 7 there was no reply sign of German Naval operations. On three September three German submarines entered the Gulf of Riga and shelled retreating Russian troops. All shipping got clear of Riga and reached Moon Island Sound. Commander-in-Chief Baltic Fleet thinks moral shock caused by quick fall of Riga may prove improve morale of his fleet. Report on 8th September indicated no change in conditions Gulf of Riga. Gulf of Finland extensively mined and naval operations there would involve elaborate sweeping operations on extensive scale. Russians very expert and thorough in mining work. Lack of tides Gulf of Finland facilitate mine laying and increase efficiency of fields. No knowledge of plans of Russians for destroying their fleet. Not considered desirable at present to inquire concerning such plans owing probability of discouraging the officers now doing their best to render Fleet effective. Considered very improbable that enemy will attempt advance on Petrograd owing to advanced season. Expect them to organize Riga as winter quarters and base for possible spring offensive. Critical period for naval operations will occur in spring on breaking up of ice which will necessitate renewal of mine fields which are destroyed every spring by ice packs. Admiralty considers no immediate cause of anxiety as to enemy operations particularly naval before critical period in spring. 16310.
Source Note: Cy, DNA, RG 45, Entry 517B.