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Vice Admiral William S. Sims, Commander, United States Naval Forces Operating in European Waters, to Rear Admiral Henry B. Wilson, Commander, Patrol Forces in France

November 25, 1917.

From:     Force Commander.

To:       Commander Patrol Squadrons operating on French Coast.

Subject:       Speed as a protection against Submarines.

               The Force Commander wishes to make it clear that speed alone does not guarantee immunity from submarine attack. Speed merely makes it more difficult for the submarine to get in position to deliver a favorable attack, and more difficult to make a hit with a torpedo. A fast ship crosses the zone in a shorter time and hence can take advantage of darkness in passing the most dangerous areas, and is exposed for a shorter time to submarine activities.

               It is quite likely however that a faster ship may zigzag directly toward a waiting submarine. The MINNEHAHA, speed 14 ½, was sunk a few weeks ago by relying entirely on her speed and zigzagging.1 She declined an offer of an escort be cause the escort would have delayed her 24 hours. In the past few weeks, the American Line speed 18 knots,2 have been attacked three times by submarines while not under escort. Once the torpedo crossed the stern, once the submarine appeared a few hundred yards on the bow and was driven under by the steamer heading directly for him; and once a submarine, having apparently failed to get into position to deliver an attack came to the surface and engaged the ST. LOUIS with gunfire for twenty minutes or more, shells straddling the3 ship.

               There is a further advantage in escorting all classes of ships in that if a submarine does <e>lect to make an attack the escorting destroyers may have an opportunity to engage him with depth charges or gunfire.

               There is always the likelihood that a fast vessel may have to slow due to machinery defects, and so lost the partial protection given by her speed.

          It is the policy of the Force Commander to provide escort for all ships regardless of their speed. It is adviseable to group vessels of the same type and similar speed together as far as it can be done. Where a single vessel is of a speed considerably greater than others of a group that vessel should be escorted separatley [i.e., separately] by two destroyers, one on each bow.


Source Note: Cy, DNA, RG 45, Entry 517B. Identifying numbers at the top of the first page. In the left-hand corner: “C/ 3106.” In the right-hand corner: “11-2-3” and in columnar fashion: “3/C/H/1.”

Footnote 1: S.S. Minnehaha was a 13,443-ton ocean liner. It was sunk off Fastnet, the most southerly point of Ireland, on 7 September 1917. It sank in four minutes and forty-three fatalities., Accessed on 13 November 2017,

Footnote 2: The American Line was a steamship company.

Footnote 3: S.S. ST. LOUIS was a passenger liner of the American Line. It avoided the torpedo attack on 30 May and engaged the submarine on 25 July. In 1918 it was taken over by the Navy and served as a troop transport and renamed Louisville because there was already an armed cruiser ST. LOUIS. DANFS.