Vice Admiral William S. Sims, Commander, United States Naval Forces Operating in European Waters, to Department of the Navy
ADMIRAL SIMS’ CABLE OF JUNE 28, 1917.
“Referring to Department’s opinion reported in last two cables to the effect that adequate armament and trained crews constitute one of the most effective defensive anti submarine measures, I again submit with all possible stress the followin[g] based on extended British war experience. The measures demanded if enemy defeat in time is to be assured are not defensive but offensive defensive. The merchantmen’s inherent weakness is lack of speed and protection. Guns are no defense against torpedo attack without warning which is necessarily the enemy method of attack against armed ships. In this area alone during the last six weeks thirty armed ships were sunk by torpedoes without submarine being seen although three of these were escorted each by a single destroyer. The result would of course been the same no matter how many guns these ships carried or what their calibre. Three mystery ships heavily manned by expert naval crews with much previous experience with submarine attack have recently been torpedoed without warning. Another case within the month of mystery ship engaging submarine with gun fire at six thousand yards but submarine submerged and approached unseen and torpedoed ship at close range. The ineffectiveness of heaviest batteries against submarine attack is conclusively shown by Admiralty’s practice always sending shown by Admiralty’s practice always sending destroyers to escort their men-of-war. The comparative immunity of the relatively small number American ships especially liners is believed here to be due to the enemy’s hopes that the pacifist movement will succeed. Cases are on record of submarines making successful gun attacks from advantageous sun position against armed ships without ship being able to see submarine. I submit that if submarine campaign is to be defeated it must be by offensive measures. The enemy submarine mission must be destruction of shipping and avoidance of anti-submarine craft. Enemy submarines are now using for their final approach an auxiliary periscope less than two inches in diameter. This information just acquired. All of the experience in this submarine campaign to date demonstrates that it would be a seriously dangerous misapprehension to base our action on the assumption that any armament on merchantmen is any protection against submarines which are willing to use their torpedoes. The British have now definitely decided the adoption to the maximum practicable extent convoys from sixteen to twenty ships. This is an offensive measure against submarines as the latter will be subject to the attack of our antisubmarine craft whenever they come within torpedoeing distance of convoyed merchantmen. Moreover it permits of concentrated attack by our forc[e]s and obliges the enemy to disperse his forces to cover the various route of approach.
Concerning Departments reference to a scheme for protection of merchant shipping which will not interfere with present escort duties, I submit that the time element alone prevents utilization of any new anti submarine invention. The campaign may easily be lost before any such schemes can come into effective operation. The enemy is certainly counting on maximum effort being exerted before long nights and bad weather of autumn. that is, in next three months. Heaviest effort may be anticipated in July and August. I again submit that protection of our coast lines and of allied shipping must necessarily be carried out in field of enemy activity if it is to be effective. The mission of the allies must be to force submarines to give battle. Hence no operations in home waters should take precedence over or be allowed to diminish the maximum effort we can exert in area in which enemy is operating, and must continue to operate in order to succeed.
Source Note: Cy, DLC-MSS, William Sims Papers, Box 22.