Naval History and Heritage Command

Vice Admiral William S. Sims, Commander, United States Naval Forces Operating in European Waters, to Vice Admiral Sir Roger Keyes, Commander, Dover Patrol

April 23rd 1918.        

My dear Admiral,

          Referring to your letter of April 10th,1 the members of my Planning Section have now returned from Queenstown and the following are the only suggestions they have to make concerning possible operations in the Dover Straits:-

1.  A sound barrage established somewhere between Dover and Ostend. This is by means of what is known as the K tube, the object of which is to notify the approach of submarines through these appliances. They have worked out rather successfully on the other side and I believe they have been considerably improved since then. We are also going to install them in the Otranto Straits.

2.  It is thought a surface barrage would of course be very useful, providing a mine can be devised that will ensure that it will stay at a constant depth below the surface during all states of the tide and current. The problem of developing such a mine and gear was suggested for solution byour own Bureau of Ordnance, but I do not know what progress has been made. I realize of course, that this is a difficult proposition; that any appliance that is supposed to work automatically month after month under water must be a very good one indeed.

          Needless to say we are all rejoicinger [i.e., rejoicing over] the success of the gallant operation that was carried out last night against Zeebrugge and Ostend.2 This should have a very marked deterrent effect upon the small submarines and will surely have a very great moral effect upon all of the Allies.

Very sincerely yours,