UMNER-CLASS
DESTROYERS
By A. D. Jensen
The first units of the Allen M. Sumner-class (DD-692) were featured in
the July-August-September 1998 newsletter. We continue their histories,
beginning with this segment on the genesis, specifications, and general
arrangement of the class.
The origins of the DD-692-class can be traced to a meeting of the U.S. Navy's
General Board on 28 October 1941. A group of senior naval officers, the Board
represented the Office of the Chief of Naval Operations and the various navy
bureaus. Its primary purpose was to establish the mission requirements and
characteristics for U.S. Naval vessels. In October 1941, the Board met to
consider improvements in the 2, 100-ton Fletcher-class destroyers. The
meetings primary goals were to improve the Fletchers antiaircraft
battery and reduce their silhouette. Board members considered seven designs,
and when the Secretary of the Navy approved the final one on 11 May 1942, it
bore little resemblance to the Fletchers except in hull and machinery.
As originally designed, the Allen M. Sumner-class had the following
characteristics:
Measurements
Length overall: 376'-6"
Extreme beam: 40'- 10"
Displacement: 2,200 tons Standard
Machinery
Four boilers
Two sets geared turbines
Two shafts/screws
Shaft horsepower: 60,000
Speed: 35 knots
Armament
Three, twin 5-inch/38 cal. gun mounts
Two, quadruple 40-mm and two, twin 40-mm gun mounts
Ten, single 20-mm gun mounts
Two, quintuple 21-inch torpedo tubes
Two depth charge release tracks (for 600 pound-charges)
Six, single K-Gun depth charge throwers (for 300 pound-charges)
Manning
Officers: 20
Enlisted: 325
The Sumner-class hulls were nearly identical to their Fletcher-class
predecessors having only about a foot wider beam and twin rudders. Topside,
however, the Sumners' arrangement differed widely, having a larger
bridge area, three, twin 5-inch/38 cal. gun mounts, and a heavier anti-aircraft
battery. These improvements made the Sumners 150 tons heavier than the Fletchers.
Their machinery was also nearly identical to that of the Fletcher-class
and the additional displacement reduced their speed by about three knots.
Furthermore, the two large twin gun mounts forward caused them to be heavy by
the head and more prone to damage in the forecastle area by boarding seas.
The twin 5-inch gun mounts and increased anti-aircraft battery also required a
larger electrical output than in the Fletchers, and the capacity of the
two ships' service generators was increased from 250 kw to 400 kw. An
additional 100-kw emergency diesel generator was added for a total of two. A
second evaporator was also added to meet the needs of the additional crew.
Three, twin 5-inch gun mounts, instead of the five single gun mounts in the Fletchers,
considerably reduced topside clutter and allowed greater arcs of fire for they
40-mm and 20-mm guns. Several internal topside features were introduced in the
new ships. They were the first U.S. Navy destroyers designed with a Combat
Information Center (CIC) and their enlarged bridge area easily accommodated
this feature, as well as the radio room, the crypto room, and an open bridge. A
longitudinal passageway on the port side, with a midships passageway to the
starboard side, afforded the crew sheltered access fore and aft to all of the
essential spaces below the main deck.
Nearly all of the Sumners surrendered their aft torpedo tubes to an
additional quadruple 40-mm gun mount soon after becoming operational, and this
change became standard for those units still under construction.
By late 1944, as the speed and power of aircraft greatly increased, the 40-mm
and 20-mm mounts were less effective, and the Bureau of Ordnance (BuOrd) began
developing a 3-inch automatic weapon as a replacement for the 40-mm guns. When
World War II ended, work on the 3-inch gun slowed. The first installations in
the fleet were not made until 1949. With the beginning of the Korean War in
1950, the 3-inch replacement and conversion program was well under way. The new
guns did not really change the Sumners' familiar silhouette. More
noticeable was a new tripod mast for the postwar SPS-6C air search radar.
After World War II, the emerging Soviet submarine threat was a major concern.
New Soviet submarines began to appear, engineered and built from the technology
of the German-type XXI U-boats. In response, the U.S. Navy began developing new
anti-submarine warfare (ASW) weapons and sonar systems, drawing upon experience
with the German submarine 'wolf packs' during the Battle of the Atlantic. The Gearings,
a fourteen-foot stretch version of the Sumners, offered an ideal
platform for obtaining vital operational testing of the new systems at sea.
Together, the Sumner-Gearings played a crucial role in developing
weapons and tactics to combat the Soviet submarine threat. During the 1950s,
this resulted in two major stand-off weapons, the Drone Anti-Submarine
Helicopter (DASH) and the Anti-Submarine Rocket (ASROC).
By 1960, both the Sumner and Gearing classes were aging and in
need of major overhaul and reconstruction to accommodate the new weapons
systems. After careful analysis of the situation, the Secretary of the Navy
ordered the beginning of the Fleet Rehabilitation and Modernization (FRAM)
program. This amounted to a complete refurbishment of the ships' hulls and
machinery and the addition of new superstructure.
The FRAM program consisted of two levels of modernization; the more extensive
FRAM I reconstruction and the somewhat less extensive FRAM II modernization.
The FRAM I program involved installation of both the ASROC and DASH systems.
The FRAM II program was developed primarily for the Sumners, which had
insufficient hull length amidships to accommodate the ASROC system. In the FRAM
I reconstructions, one of the twin 5-inch gun mounts was removed as weight
compensation for the ASROC system, but the FRAM II modernizations kept all
three of their 5-inch gun mounts. They also had a variable-depth, towed-array
sonar system fitted on the stem. The FRAM program completely changed the
silhouettes of the Sumners and Gearings into a more boxy but
modern appearance. Twenty Sumners serving as Naval Reserve training
ships were not scheduled for FRAM II modernization.
By the mid-1970s, all of the Sumners and Gearings had been
retired from U.S. Naval service, however, a number of them remained active in
foreign naval service. Two survive today as memorials in the historic fleet and
are supported by grants from Tin Can Sailors, Inc. The USS Laffey
(DD-724), a Sumner, is at Patriots Point Naval Museum, Mount Pleasant,
South Carolina. The USS Joseph P. Kennedy, Jr. (DD-850), a Gearing,
is at the Battleship Cove, Fall River, MA.
From The Tin Can Sailor, January 2000
