Vice Admiral William S. Sims, Commander, United States Naval Forces Operating in European Waters, to Admiral William S. Benson, Chief of Naval Operations
<6 October 1917>
#773 Referring Departments 13202 to Naval Attache and Opnav 592 and my 745 concerning enemy submarines destined for American waters period Similar information also repeated from Paris period Similar information obtained by Admiralty representatives Norway and Denmark but latter reports that investigation indicates source unreliable and strong suspicions that information of this character is being transmitted by enemy broadcast and particularly through their agents in neutral countries possibly with int
nent of influencing US government plans period Admiralty has no reliable evidence to corroborate this information period During the last three years much unreliable information of this character received particularly from Copenhagen period. The Admiralty considers it has been work of enemy to influence disposition of allied forces period Information in hand at present indicates 24 sea-going submarines at sea of which 13 have been located in Atlantic within 300 miles Irish coast within last ten days period Admiralty opinion that there is no reliable evidence at present to indicate any extensive over-sea sea-going submarine operations and that even if such attempts were made it would according to all past experiences be by small numbers of sea-going submarines for principal purpose of influencing disposition of forces period The Admiralty information concerning war experience of sea-going submarines both Allied and enemy indicates they can not remain long in service without docking period Average length of cruise so far about 28 days period New sea-going submarines particularly experience material difficulties similar to US and British sea-going submarines period Admiralty information indicates no more than two large sea-going submarines Deutschland type completed of which one apparently now at sea vicinity Azores.11106.
Source Note: Cy, DNA, RG 45, Entry 517B. Document Reference: “Op 19 Op 28 ONI.” The date is handwritten and seems to have been added later.