USS Sea Devil
SS 400

The "4-Oh Boat"
SS400 Emblem

Sea Devil; Manta birostria, the largest of all rays, noted for power and endurance.


Displacement: 1,526 tons (surfaced), 2,321 tons (submerged)
Length: 311 feet, 6 inches
Beam: 27 feet, 3 inches
Diameter: 15 feet, 3 inches
Speed: 20 knots (surface), 9 knots (submerged)
Crew: 66
Armament: One 5-inch gun; one 40mm gun; one 20mm gun; ten 21-inch torpedo tubes
Class: Balao



The Sea Devil (SS-400) was laid down on November 18, 1943 at the Portsmouth (NH) Navy Yard and launched February 28, 1944, sponsored by Mrs. Sherman K. Kennedy. The Sea Devil was commissioned May 24, 1944, Commander Ralph E. Styles commanding.

Completing shakedown training at New London (CT), Sea Devil departed that port on July 11, 1944 and arrived at her home port, Pearl Harbor (HI), on August 9 to join Submarine Division (SubDiv) 281 and prepare for her first patrol.


On September 3, she sailed west from Pearl Harbor. By the 15th, she was 500 miles off Honshu, and during the early morning darkness, made contact with her first enemy ships -- two sampan-type patrol vessels. Rough seas, however, precluded an attack and she continued on to patrol in the shipping lanes to Japan's major ports: Yokohama, Kobe and Osaka.

On September 16, 1944, at 0432, Sea Devil made her second contact. She submerged and commenced closing the target. At 0538, the enemy, a Japanese submarine, was sighted. At 0545, Sea Devil made her first attack. Four torpedoes were fired. Two exploded against the target. The submarine lost depth control. A minute later, periscope depth was regained. Brown smoke marked the enemy's previous location. Seven underwater explosions followed. By 0553, a large oil slick covered the site where I-374 had gone down.

Sea Devil reloaded and continued to move closer to Japan. On September 17 and 18, mountainous seas inhibited hunting. On the 21st, the submarine commenced running along the 100-fathom curve, but the strong Kuroshio Current there caused her to lose ground and forced her to shift course.

On the morning of September 22, 1944, Sea Devil made several contacts, but all were too small. During the early afternoon, she sighted a small convoy and fired on a freighter. The target turned toward the submarine and she went deep. An hour later, the surface ships had gone, and the hunted submarine again became a hunter.

During her remaining 22 days on station, Sea Devil attacked several targets, but scored on none. In mid-October, she headed for Majuro for refit.


On November 19, 1944, Sea Devil got underway for the waters west of the Nansei Shoto. At the end of November, she entered the East China Sea and turned toward the Kyshu coast. On December 1,1944, just prior to midnight, she made radar contact with a distant convoy and commenced running with the "state-5" sea on four engines to gain position. At 0239, on December 2, she changed course to close the convoy. A minute later, she took a wave over the bridge which knocked the starboard lookout onto the bridge deck; flooded the main induction and both engine rooms to the lower deck plates; and sent water through the supply line into the after battery compartment, crews mess, and the radio shack. A solid stream came into the control room via the conning tower. But, other than numerous electrical grounds, no damage was sustained.

By 0320, Sea Devil was 1,200 yards ahead and 3,000 yards off the port track of the convoy. The radar showed eleven definite targets and indicated the presence of others. Weather and visibility, however, worked against a night surface attack.

At 0322, a floating mine was sighted less than 100 yards off the port bow. Sea Devil swung full right with full rudder. Ten minutes later, she submerged and commenced her approach, heading for the port flank of the convoy.

By 0400, the moon had clouded over. Periscope observations became progressively more difficult. At 0413, an escort vessel, sonar pinging, passed Sea Devil close aboard. Sound conditions were (fortunately) also poor.

At 0414, Sea Devil commenced firing. four Mark 18 torpedoes headed for a medium-sized freighter, but all missed. At 024, she fired No. 5 and No. 6 tubes at a large ship 600 yards away. Forty seconds later, the torpedoes hit, throwing a huge column of debris into the air. At 0425, Sea Devil swung right to avoid an escort ahead of the ships in the center column.

By 0427, water was over the deck of the stricken merchant ship. At 0428, another escort passed Sea Devil. A minute later, the submarine fired four torpedoes from her stern tubes at a large passenger/cargo maru 1,300 yards away. A look around through the periscope then revealed a larger freighter in the center column less than 150 yards away and headed directly for the submarine.

Sea Devil went deep. At 0430, she was jolted by a tremendous explosion. Her torpedoes had hit and, from the concussion, it appeared that the targeted ship had been carrying ammunition. "Breaking up" noises quickly followed the explosion.

Sea Devil leveled off at 500 feet and rigged for depth charging. Twelve were counted; none was close. Escorts milled about overhead for the next 40 minutes; then the sound of screws faded out. Pinging was heard for a while longer, and distant depth charges were heard for several hours.

After sinking Akigawa Maru and Hawaii Maru, the Sea Devil continued to patrol the sea lanes to Kyushu. On December 4, 1944, she received a positive ship contact report from a China-based B-29, but the position was too distant. On December 5, she sighted only two small fishing trawlers. Then, on the evening of December 8, she made radar contact with four distant targets zigging on various courses toward Nagasaki.

Sea Devil went to flank speed and began gaining slowly. At 16,000 yards, the radar pips were estimated to be one battleship (BB) or aircraft carrier (CV), two light cruisers (CL), and four destroyers (DD). Darkness and intermittent rain squalls interfered with visibility.

By midnight (0000), December 9, Sea Devil had gained a good position 10,000 yards ahead of the nearest escort and 3,000 yards off the port track of the largest radar pip. At 0005, she began a submerged radar approach. At 0017, she began tracking by sound and, ten minutes later, she fired four Mark 23 torpedoes at the target. Two hit. Poor visibility precluded a damage assessment.

Sea Devil went deep and rigged for depth charging but, by 0050, the sounds of searching surface ships faded out. At 0107, the submarine surfaced and headed up the target's track. An hour later, she reversed her course and headed back to her patrol area. That evening, Plaice (SS-390) confirmed Sea Devil's hits, but was unable to provide a damage estimate. Later reports identified the damaged warship as the aircraft carrier Junyo, which was subsequently damaged further by Redfish (SS-395). Junyo remained in the repair yard through the end of the war.

In mid-December, Sea Devil moved farther south to patrol off Okinawa; and, on December 29, she headed for Midway enroute to Pearl Harbor.


On February 7, 1945, Sea Devil departed Pear Harbor and arrived, February 19, at Saipan for training in wolfpack tactics. On February 27, Sea Devil sailed for the Yellow Sea in company with Tench (SS-417), Guardfish (SS-217) and Balao (SS-285). At the end of February, Sea Devil was diverted to search for downed aviators and, on March 3, continued on to her patrol area to further decrease the declining traffic between China and Manchuria, and the Japanese home islands.

For over a week, fishing junks, sailing junks and floating mines provided the only contacts. On March 24, Sea Devil sighted a large tanker with four escorts but lost the convoy. The next day, she sighted and evaded a Japanese hunter-killer group. On March 29, she sank or exploded four mines and attempted to do the same to two others.

Fog shrouded Sea Devil's patrol area during the lst days of March, 1945. On April 2, visibility was still poor, less than 1,000 yards. At 0710, she made radar contact with an enemy convoy -- four merchantmen and three escorts. At 0915, she commenced firing at the lead merchant ship. Forty seconds later, she fired at the next ship. Then, swinging around to bring her stern tubes to bear on a third merchant ship, found herself well-inside the escort on the convoy's starboard quarter. Sea Devil continued swinging around and fired three stern shots at the escort. Between 0819 and 0822, seven hits were heard and felt.

Sea Devil then left the formation and opened range to reload. The radar screen now showed only three small pips. The third torpedo of the first salvo had apparently missed its target and run on th hit the third maru (merchant ship).

After reloading, the submarine tracked the remaining units of the convoy. Shortly after 1000, she fired on, and damaged, one of the escorts. Forty minutes later, she fired on the remaining merchantman and observed it suddenly disappear from the radar screen. After 1100, she made her way through the wreckage to pick up survivors. Only four allowed themselves to be picked up and, of these, one died of his wounds.

Of the seven ships, Sea Devil had sunk three -- Taijo Maru, Edogawa Maru and Misshan Maru, and had damaged the fourth maru and at least one of the escorts.

Sea Devil remained in her Yellow Sea patrol area for another three days, then headed for Midway. On April 6, however, she received orders to patrol south of Kyushu and, on April 8, was ordered closer to Okinawa in search of four downed Marine Corps pilots.

The pilots, from the Essex, had been covering the movements of the battleship Yamato and, on running low on fuel, had ditched in a location they thought to be near Okinawa.

Prior to midnight, April 8, Sea Devil located three of the pilots 200 miles northeast of Okinawa. The search for the fourth continued through the night. With dawn on April 9, friendly planes joined in the search. But they, too, were unsuccessful and, in the late afternoon, the submarine continued south-eastward.

On April 13, 1945, Sea Devil arrived at Saipan. On April 20, she completed her third patrol, for which she was awarded the Navy Unit Commendation, at Midway.


May 28, 1945, Sea Devil arrived back at Saipan and, on May 30, Sea Devil, together with Ronquil (SS-396) and Paddle (SS-263), got underway for the East China and Yellow Seas. On June 6, Sea Devil entered the East China Sea via Tokara Kaikyo and headed northward to the Yellow Sea. On June 7, she made her way through the islands of southwestern Korea and, on April 8, commenced patrolling between the Shantung peninsula and Korea.

On the afternoon of June 14, a cargo ship, with an escort on either side, was sighted through the high periscope. Sea Devil submerged; maneuvered into position; fired four torpedoes "down the throat;" then changed course radically to avoid collision with the target. Twenty-three seconds after firing, two of the torpedoes hit the target. Wakamiyasan Maru went under. Her escorts dropped depth charges. Five were fairly close. Sea Devil dropped beneath a 20-degree temperature gradient and worked her way out.

On the morning of June 21, Sea Devil sighted three armed trawlers, one under tow, headed from Shantung toward Korea. At 0943, she surfaced and, three minutes later, commenced firing with her 5-inch, 40-millimeter and 20-millimeter guns. The 40mm soon jammed, but fire from the 5-inch and 20mm guns sank the trawler being towed and left a second burning and settling. The third (the towing vessel) cast loose and headed west under full steam. Sea Devil picked up three survivors and moved south to patrol in another area.

Poor weather impaired hunting during the next six days. On June 27, however, Sea Devil was able to take photographs of Saishu To and Chiri To and, on June 29, was diverted to search and rescue operations.

Assisted by a Coronado and a PBM, Sea Devil picked up a PBM crew from Rescue Squadron 4, Kerama Retto, on the evening of June 30; then located the pilot of an Army P-47 based at Ie Shima. Another man, who had become separated, was located by accompanying aircraft the following morning and was picked up before noon.

Sea Devil remained on life guard duty in the northern Ryukus and southern Kyushu area until July 10, then headed east to Guam for refit and installation of LORAN equipment and a radio direction finder (RDF).


On August 9, 1945, Sea Devil headed back to the Yellow Sea. On August 14, she transited the Nansei Shoto, passing south of Akuseki Shima. On August 15, after entering her patrol area, she received word of Japan's acceptance of Allied surrender terms.

For another two weeks, Sea Devil remained in the area, looking for and sinking mines. On August 27, she sighted a fishing vessel near a mine. Closer inspection showed that the fisherman was using the mine as a bouy and had secured his net to the mine horns! On August 28, the submarine was ordered to Guam; then diverted to Subic Bay, where she arrived on September 3, 1945.

Sea Devil earned five battle stars for her service in World War II.


Within a few weeks, Sea Devil was joined by seven other submarines of the new, post-war Submarine Squadron (SubRon) 5. Through the Fall of 1945, she operated out of Subic Bay, conducting intensive training operations necessitated by a heavy turnover in personnel. On December 1, Sea Devil sailed for San Francisco for overhaul and, on April 23, 1946, she returned to her home port, Pear Harbor.

Three days later, Sea Devil again headed west. On May 16, she returned to Subic Bay and, May 23, she continued on to Tsingtao where she provided antisubmarine warfare training services to TF 71 into July. On July 5, she sailed for Shanghai and, from there, returned to Pearl Harbor. From July 26, 1946 to May 5, 1947, she conducted operations in the Hawaiian area. Sea Devil returned to Mare Island for overhaul during the summer. In early October, she returned to Hawaii. On October 27, 1947, she sailed westward for another tour in the Far East.

A simulated war patrol and the provision of ASW training services occupied Sea Devil during her deployment and, on January 8, 1948, she returned to Pearl Harbor where she operated until ordered to Mare Island for inactivation.

Sea Devil was de-commissioned September 10, 1948 and remained in the inactive reserve (mothball fleet) through the end of the decade. Two months after the outbreak of hostilities in Korea, however, she was ordered activated. On March 2, 1951, Sea Devil was re-commissioned, assigned to Submarine Division (SubDiv) 71, SubRon 7, and based at Pearl Harbor.

Through the summer of 1951, Sea Devil operated in Hawaiian waters. In September, she returned to the west coast (California) to provide ASW training services for Fleet Air Wing 4 in the Puget Sound area. In mid-November, she returned to Hawaii, where she conducted local operations through the winter. From mid-April to mid-June, 1952, she underwent overhaul at the Pearl Harbor Naval Shipyard; then resumed local operations. In late September, she sailed west for her first deployment to the western Pacific since re-commissioning.

Sea Devil arrived at Yokosuka on October 7, 1952, and commenced providing services to TF 96, which conducted ASW training exercises and maintained preparedness for hunter/killer operations in support of the United Nations effort. In late January, 1953, she was detached for patrol purposes. Toward the end of January, she returned to Yokosuka and, on March 3, she sailed for Pearl Harbor.

On June 30, 1953, Sea Devil again got underway for Puget Sound where she, again, provided services to Fleet Air Wing 4 before heading for San Francisco on August 20 to begin inactivation. On August 28, she was placed in commission, in reserve and, February 19, 1954, was de-commissioned.

Three years later, Sea Devil was again activated. August 17, 1957, she was re-commissioned and assigned to SubRon 5 at San Diego. For the next year, she conducted training operations off southern California and in the Puget Sound area, then prepared for deployment to the western Pacific. From November 1958 to April 1959, she provided services to Seventh Fleet surface units and to Fleet Marine Force -- Pacific. In May, she returned to San Diego. On July1, 1960, she was re-designated AGSS-400 and, from that time through 1963, she was engaged, primarily, in training operations off the west coast. Only two deployments to the western Pacific, February-August, 1961 and June-December 1963, interrupted that schedule. With the year 1964, however, Sea Devil commenced inactivation for the last time. On February 17, 1964, she was de-commissioned. Her name was struck from the Navy list the following July (1965) and she was subsequently sunk as a target.

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