Naval History and Heritage Command

Vice Admiral William S. Sims, Commander, United States Naval Forces Operating in European Waters, to the Office of the Chief of Naval Operations

CABLEGRAM SENT 7 April 1918   RES1

To Opnav Washington                     Ser. No. 6151

Prep. by CS    NCT2

          25 D

VERY SECRET

6151.     Your 4487 and 4570.3    Upon preliminary consideration of plan opinion of Admiralty in which I concur is that submarines based as suggested would probably have the effect of denying the adjacent waters to cruising submarines. Admiralty experience is that hostile submarines have almost invariably moved their hunting ground when they have discovered the presence of allied submarines. It is not thought that vessels of “P” type would be useful for operating with submarines, but vessels of “Q” type probably would be.4 Thorough examination of charts of available harbors will be made to determine possibility of using them as bases. Admiralty will at once take up with British Government the matter of obtaining permission to establish bases in Portuguese Islands. 6151.

Sims.