Blockade of Wonsan The Blockade of Wonsan , or the Siege of Wonsan , from February 16 , 1951 to July 27 , 1953 , during the Korean War , was the longest naval blockade in modern history , lasting 861 days . UN naval forces , primarily from the United States , successfully kept the strategically important city of Wonsan from being used by the North Korean Navy . The blockade also served to divert communist troops from the front line . North Korean resistance used artillery to oppose the American fleet , although this was mostly ineffective , and the city was heavily damaged by UN naval aircraft and warships . Background . Operation Wonsan . Wonsan was a strategic point during the war , located on North Korea ' s southeastern coast with a large harbor , an airfield , a petroleum refinery , 75 , 000 people , and as many as 80 , 000 troops , including several artillery batteries . After the Battle of Inchon , in which General Douglas MacArthur landed on the northwestern shores of the Korean peninsula , he ordered X Corps to make a landing at Wonsan where they would proceed west , link up with the Eighth Army and then advance towards Pyongyang , the capital of North Korea . North Korean naval forces had been well supplied by the Soviet Union and China with all sorts of sea mines and they were used as much as possible to defend Wonsan . Soviet military advisors were also employed to create more effective mine fields . One of the first objectives of the blockade was to begin plotting the locations of mines and then destroy them . Because of this , the use of minesweeper s became a necessity and eventually dozens would serve in the blockade . Operation Wonsan , or the Clearance of Wonsan , began on October 10 of 1950 , ten days before the landing was scheduled to take place . Rear Admiral James H . Doyle commanded Task Force 90 , a fleet of dozens of American warships which were used in the clearance . Two days later on October 12 , mines sank the sweepers USS " Pledge " and USS " Pirate " , killing twelve men and wounding dozens of others , all while under accurate fire from North Korean shore batteries . The United States Navy Pacific Fleet responded by starting the production of new minesweepers in the largest shipbuilding program since World War II . Other vessels were damaged by mines and battery fire as well but the loss of the " Pirate " and " Pledge " proved to be the major engagement during the operation . Operation Tailboard . Operation Tailboard was the codename for the United States Army landing at Wonsan , and it was found to have been unnecessary . Preparations began over 800 miles away at Inchon where on October 15 , thousands of marines and soldiers , 30 , 184 in total , embarked transports to participate in the landing . When they arrived off Wonsan on October 20 , the clearance of the mine fields was still taking place so for five days X Corps and the 1st Marine Division were forced to remain on ship to wait for a clear path to the beaches . When it came time to land on October 15 , the North Koreans had already withdrawn and the British and South Koreans were securing the area . Ultimately the landing was not needed and MacArthur was criticized for not using the X Corps in the pursuit of the retreating North Korean Army on the Inchon front . On October 19 , the South Korean Army captured Pyongyang so instead of heading there the American army went north along the coast to occupy Hungnam and the Chosin Reservoir areas while the 3rd Infantry Division landed at Wonsan in November as reinforcements . Evacuation of Wonsan . UN forces would not hold Wonsan for long : after the massive Chinese intervention in the war , Allied forces were ordered to evacuate Wonsan on December 9 , 1950 , taking 7 , 009 refugees , 3 , 384 military personnel , 1 , 146 vehicles and 10 , 013 tons of cargo in the process . General MacArthur ' s plan was to regroup in Japan before launching another offensive , while holding Pusan Perimeter . When the North Koreans and Chinese recaptured the city , defenses were rebuilt in a more formidable way , additional sea mines were deployed and new artillery batteries were erected . Blockade . Opening Engagements . The blockade began on February 16 , 1951 and would last 861 days until the armistice in July 1953 . During nearly three years of blockading United States Navy ships and aircraft engaged shore batteries repeatedly . Several American vessels were damaged by land based artillery fire though none were destroyed . UN Tast Group 95 . 2 was assigned to the blockade and they first bombarded Wonsan on February 17 , 1951 , targeting everything used by the communists and causing heavy damage . On February 19 , the destroyer USS " Ozbourn " , under Commander Ross E . Freeman , was fired on by shore batteries in the Wonsan area . She received two direct hits and several near misses and successfully rescued a downed pilot from the " Valley Forge " with a motor boat , while he was adrift in a mine field . The coxswain of the boat received a Bronze Star for the rescue . " Ozbourn " eventually returned to San Diego in April 1951 for repairs and later sailed back to North Korea . On February 24 , the undefended island of Sindo - ri , in Wonsan Harbor , was captured by South Korean marines supported by two American destroyers and two frigate s . Wonsan shore batteries also dueled with UN warships on March 3 , but there were no recorded hits . The battleship USS " New Jersey " participated in her first shore bombardment mission of the war on May 20 , 1951 . While patrolling off Wonsan , North Korean batteries opened fire and she was struck by one shell . Slightly damaged , she sustained one man killed and two wounded , her only casualties during the war . Another shot was a near miss and passed over the " New Jersey " from aft to port . She then responded by bombarding the enemy position until they were silenced . The type of warfare experienced at Wonsan would last throughout the war . Operation Fireball . Operation Fireball was the code name for a bombardment of the Wonsan area from May through September . It involved the cooperation of naval vessels and aircraft from the 5th Air Force which caused heavy damage to the North Koreans . On the night of May 21 and May 22 , during the height of the fighting , two American LSMR s , supported by light cruiser s and destroyers , fired 4 , 903 rocket s in thirty - five minutes , further damaging the defenses of the city . UN carrier aircraft were used to fire flares while the warships focused on gunnery . It was the first time LSMRs would be deployed in the siege of Wonsan and over time would cause heavy casualties to the North Korean garrison . Between June and September the LSMRs would discharge a total of 12 , 924 5 - inch rockets . During the operation , destroyer USS " Brinkley Bass " was slightly damaged while engaging a battery , she sustained eight casualties in the action . Action off Rei - To . On May 24 , the UN station ship at Wonsan detected several small craft southeast of Rei - To Island . In a one sided night engagement , the light cruiser USS " Manchester " and the " Brinkley Bass " used radar to direct their fire and broke the enemy formation . Four sampans were recovered the following day along with the bodies of eleven enemies , one other wounded North Korean was taken prisoner and the sampans were found to have been converted to minelayer s , with four M - 26 mine s each . USS Walke Incident . USS " Walke " was a destroyer , under Captain Marshall Thompson , of Task Force 77 which was by now assigned to naval operations in the Wonsan area . On June 12 of 1951 , the " Walke " was about sixty miles off the coast of North Korea , at position 38 - 52 N , 129 - 25 E , when she was struck either by a torpedo or a floating sea mine which had separated from a field . The resulting explosion severely damaged the " Walke " s hull on her port side and twenty - six men were killed and forty others wounded . Many of the casualties were blown over the side and into the water when the explosion occurred and it took a long time before all of them could be recovered . Shortly thereafter , sailors on the nearby destroyers USS " Hubbard " and USS " Bradford " spotted an oil slick off of " Walke " s starboard side so they began dropping depth charge s on what they reported as being two submarines . The chase was eventually discontinued and the damage to the " Walke " was temporarily repaired and she made for Japan . A later investigation of the incident recovered a small metal disk from the damaged ship and when analyzed it was concluded to have been part of a torpedo detonator . The " Walke " was later repaired and returned to hostile Korean waters the following year . Battle of the Buzz Saw . The Battle of the Buzz Saw , as United States Navy personnel called it , was a response to the UN ' s attacks on Wonsan . After causing heavy damage to North Korean forces within the previous months , the situation escalated as the communists started utilizing new weapons to lift the blockade . On July 6 , 1951 , the United States launched another naval bombardment of the area , causing high casualties and tempting the North Koreans to retaliate with an especially heavy bombardment on July 17 , 1951 . For four and a half hours the destroyers USS " O ' Brien " , USS " Blue " and USS Alfred A . " Cunningham " engaged the batteries at Wonsan , firing 2 , 336 rounds of 5 - inch shells . the North Koreans offered heavy resistance and over 500 splashes were counted but there was no serious damage to the American vessels . The next day USS " Evans " engaged the batteries and received four near misses , wounding four men aboard the ship . Operation Kickoff . Between late June through August 1951 , North Korean attacks on American ships seemed to increase so the United States began concentrating on destroying enemy batteries . On June 28 , destroyer USS " Henry W . Tucker " received counter - battery fire while conducting a bombardment of Wonsan Harbor . She was struck by one round , causing light superficial damage and one man was injured . A few days later on July 3 , frigate USS " Everett " was attacked by the batteries and took hits , killing one man and wounding seven others . The Americans responded with an attack by the Fast Carrier Task Force . In one day 247 bombing sorties were carried out against Wonsan and 600 South Korean marines raided the mainland from the island of Cho - do . On July 6 , destroyer USS " Evans " landed men on the island of Hwangto - do and then with two other destroyers , bombarded buildings and a torpedo station . USS " Blue " captured Kukto Island the following day and established an observation point to keep watch on North Korean positions . On July 11 , in the vicinity of Yo - do island , USS " Blue " and the " Evans " were attacked , approximately fifty splashes were counted near the ships but none of them were hit . Due to the attacks , particularly the Battle of the Buzz Saw , American naval commanders decided on launching Operation Kickoff which referred to maneuvers within Wonsan Harbor , aimed at reducing the batteries . Every day on from July 17 , 1951 , elements of the allied fleet , assigned to bombardment groups , would sail at five knots to bombard known enemy positions and continue doing so from 3 : 00 pm until dark . On the first day of the maneuvers , the LSMRs USS " LSMR - 409 " and USS " LSMR - 525 " received heavy accurate fire from enemy batteries on the islands of Kalmagak , Umi - do and Ho - do Pan - do . Both of the vessels were struck by shells and damaged but not seriously . Over 500 shells splashed in the water around USS " O ' Brien " and she sustained at least a couple of hits . One man was injured although the damage was light . USS " New Jersey " and heavy cruiser USS " Helena " also participated in the bombardment . On July 31 , the " Helena " engaged in a gunnery duel , she was hit one time before delivering counter battery fire which destroyed seven gun emplacements and an ammunition dump . There were no casualties caused by the shell striking the ship but near misses wounded two men . On August 4 , British Royal Marines installed mortar s on Hwangto - do for use in countering the North Korean shore batteries and on August 11 , USS " Hopewell " , using SFCP , fired direct and indirect fire missions against enemy troop concentrations and transportation targets in Wonsan area . Minesweepers USS " Dextrous " , USS " Heron " and USS " Redstart " also came under fire by shore batteries that same day while conducting check sweep operations in the vicinity of Hodo - pando . " Dextrous " suffered two direct hits ; killing one man , three wounded and moderate damage . With the exception of an attack on USS " Uhlmann " on August 20 , while off Hodo - pando , Operation Kickoff proved to be a success as the number of attacks on blockading ships decreased for a while until new batteries were constructed . Seven enemy guns opened fire on the " Uhlmann " that day and after a long engagement , five of the guns were destroyed and 117 splashes were counted by the sailors but there were no hits . The " Uhlmann " had to break off the attack without silencing the remaining two artillery pieces because allied patrols entered the area . Renewed Minesweeping Operations . Because the communists were still mining the approaches of Wonsan and Hungnam , the commander of CTF - 95 ordered on September 5 , the minesweeping group CTG - 95 . 6 to sweep the coastline so as to allow UN ships to remain within gunfire range of the shore at all times while blockading . Upon completion , allied warships nolonger had to withdraw out of range each night . While supporting the minesweepers involved in the mission , destroyer USS " William Seiverling " was hit three times on September 8 by ground based artillery , her fire room flooded but there were no casualties . On September 10 , the minesweepers " Redstart " and " Heron " were again damaged by shell fire from Wonsan , this time while rechecking pre - swept waters and on September 20 , USS " Orleck " bombarded enemy troops and mortar positions , scoring five hits which destroyed an ammunition dump . " Orleck " also attacked a large sampan , suspected of minelaying , and struck her four times with gunfire . On September 24 , the ROKN " PF - 62 " was also damaged by shore battery fire . After three hits , the frigate was moderately damaged and caught on fire . Three South Korean sailors were wounded but they were able to save their ship from complete destruction . Minesweeping operations would continue for months , the UN ships constantly swept various areas to ensure that no new mine fields were laid . Incidents of shore batteries scoring hits on allied warships also became less common and for weeks no vessels were damaged until October 29 when the USS " Osprey " was engaged . The " Osprey " s engine room flooded after being hit three times and communications went out , one man was seriously wounded though the ship was saved from sinking . By November 9 , the minesweeping mission was eighty percent complete , accurate shore battery fire delayed the UN ships from completing the operation for a few more weeks . Escalation of the Naval War . In late 1951 and 1952 intelligence from captured or surrendered North Koreans became more frequent and reliable . The information told the United States that the enemy was building sampans for minelaying and preparing offensives against the islands around Wonsan . MIG aircraft were also being reported in larger numbers and would begin to threaten UN aircraft and the blockading force . North Korean Army troops , well supplied by the Soviets and the Chinese , were also conducting large artillery bombardments that demonstrated their supply of ammunition . Shore batteries increased their effectiveness as well , now that fire control was being equipped , air burst rounds were also starting to be used . With the minesweeping operation mostly completed , American bombardment groups began shelling the city again . The USS " New Jersey " carried out a series of attacks at Wonsan and other nearby coastal targets from November 1 to November 6 , 1951 , during which she targeted the petroleum refinery at Wonsan , trains , bridges , tunnels , railroads , troop concentrations and shore batteries . From November 22 to 24 , LSR Division 31 , including the LSMRs , " 401 " , " 403 " and " 404 " , conducted fire missions and on November 24 and 25 , naval gunfire supported a guerrilla raid on the island of Ka - do where several North Korean prisoners were taken . On November 28 and 29 , the North Koreans launched a small offensive operation , in it , armed sampans attacked the island settlement on Hwangto - do , killing one civilian and taking five civilians prisoner . Most of the homes on the island were destroyed in the attack and the North Koreans suffered no casualties . Another large scale bombardment of Wonsan took place on December 20 , with the battleship USS " Wisconsin " participating . Six days later the ROKN " PC - 740 " was lost , presumably due to striking a mine off of To - do in Wonsan Harbor . On January 11 , 1952 , the next significant gunnery duel began when the " Redstart " and " Dextrous " received accurate battery fire from Ho - do Pan - do while they were sailing without an escort . The fire was concentrated on the " Dextrous " and she sustained considerable superficial damage and a loss of one man killed and two wounded . Later on , the USS " Gregory " and USS " George K . MacKenzie " engaged in a one hour duel with four 76 - millimeter batteries . " MacKenzie " was closely straddled with thirty - six rounds but there was no damage or casualties . She also made three direct hits on the North Korean command post . The " George K . MacKenzie " was engaged again on January 24 from Han - do Pan - do , along with the USS " Marshall " . Neither ship was damaged and there were no casualties , two 76 - millimeter mortar rounds splashed 1 , 000 yards away from the " Marshall " . TF - 77 rescued survivors from a helicopter crash on February 8 , twenty - five miles outside of Wonsan . Reports from RESCAP indicate that personnel involved were apparently in enemy hands . Heavy flak in the area was the probable cause . The grounded helicopter was also destroyed by TF - 77 aircraft . By the one - year anniversary of the blockade , bombing Wonsan occurred on a daily basis though occasionally the UN fleet would combine their firepower for larger engagements . On February 16 , exactly one year after the blockade began , USS " Gregory " , USS " Twining " and USS " Rowan " attacked in the usual bombardments that would last until the end of the war . Enemy shore batteries were active on March 13 , at Kalmagak , Wonsan against UN siege forces . Counter battery engagements by USS " Manchester " , USS " James E . Kyes " , USS " McGinty " and USS " Douglas H . Fox " , plus the help of Fast Carrier Task Force planes silenced the enemy guns . Shore battery fire was most accurate to date indicating the possible use of fire control equipment . USS " Wiltsie " and " Brinkley Bass " engaged shore batteries at Wonsan on March 20 , utilizing SFCP spotting . " Brinkley Bass " scored seven direct hits on one of the batteries located near the city of Wonsan . Neither ship was struck , but the " Bass " received some shrapnel . March 20 marked the beginning of a four - day attack on the blockade by North Korean artillery , on May 21 USS " Osprey " was taken under fire by enemy shore batteries while searching for mines . Utilizing SFCP spot , Osprey silenced three batteries and suffered no damage . " Brinkley Bass " and USS " Stickell " silenced a battery at Kalmagak on March 22 . USS " Wiltsie " received fire from the batteries east of Kalmagak on March 23 and , together with " Brinkley Bass " , responded with counter - battery fire to silence the enemy guns . During the following day the " Bass " was struck again with one round from Ho - do Pan - do , wounding five men , one seriously , and causing damage to the ship ' s radio and electronics . On March 28 USS " Burlington " was fired on from Ho - do Pan - do , shots straddled the ship but evasive maneuvers prevented probable hits . The " Burlington " responded with 123 rounds of her own and caused a small forest fire . April 1952 . USS " Leonard F . Mason " experienced an explosion in the depth charge starboard detonator locker on April 1 , while bombarding Ho - do Pan - do , no casualties were reported . The " Wiltsie " , USS " McGinty " , and USS " Condor " were also engaged in the action . USS " Symbol " , USS " Murrelet " and USS " Edmonds " received enemy fire near Wonsan on April 2 and again no damage or casualties were experienced . The same day USS " Wiltsie " received ten near misses from shore batteries east of Kalmagak while providing fire support for the " Condor " . " Wiltsie " was attacked a few more times within the next several days and they were all inconclusive contacts . In the Wonsan area on April 10 , TF - 77 carried out a coordinated strike using the guns of USS " Saint Paul " and USS " Hanson " . USS " Silverstein " , to the north of Ho - do Pan - do , received 30 rounds of enemy fire at a range of 12 , 400 yards with fall of shot fifty to 300 yards from the ship but without damaging her . The incident was taken as evidence that the North Koreans were beginning to use fire control more regularly . On April 11 , the " Wiltsie " and the " McGinty " were taken under fire by Wonsan shore batteries . Both ships conducted maneuvers in separate areas and delivered counter battery fire . " Silverstein " , USS " Cabildo " and USS " Apache " fired suppression fire against the batteries on Ho - do Pan - do . The " McGinty " was straddled by enemy shore batteries as she moved near Wonsan on April 17 . " McGinty " and the USS " Maddox " replied with counter fire and the enemy guns ceased . USS " Cabildo " was attacked again from shore batteries on April 29 from Ho - do Pan - do . Three near misses straddled ship and one direct hit amidships caused minor damage to structure and electrical wiring , two were wounded . On the same day , USS " Silverstein " and USS " Maddox " , in a swept area south of Yo - do , were covering the withdrawal of two friendly sampans from Umi - do , when suddenly enemy batteries opened fire . The sampans received the first salvos , around 30 total so the " Silverstein " and the " Maddox " returned the fire and suppressed the batteries . Aircraft from USS " Valley Forge " were also called in to provide close air support . " Silverstein " received 110 rounds of estimated 105 millimeter batteries though she was not damaged , " Maddox " received two rounds . There were no allied casualties in the action . USS " Waxbill " attacked a shore battery the following day and on April 28 the " Silverstein " , and USS " Conserver " received fire from Ho - do Pan - do . With South Korean small craft , the allied ships bombarded the opposing battery and laid a smokescreen while other nearby ships withdrew . The " Conserver " received ten rounds of estimated 122 - millimeter fire . On May 7 , USS " Waxbill " was fired on by twelve rounds but apparently did not return fire and on May 10 , while sweeping Wonsan Harbor , USS " Merganser " and USS " Redhead " received ten rounds of enemy fire from Kalmagak . Also that day , the " Maddox " and USS " Laffey " attacked North Korean railroad targets , scoring many hits , two railroad cars were damaged along with two buildings . Batteries on Kalmagak fired ten rounds of 76 - millimeter fire at the sweepers , the nearest one landing 100 yards from the ship . Counter fire by " Maddox " scored two more hits . On the next day , the " Maddox " , the " Laffey " , the " Herbert J . Thomas " and the USS " Evansville " , received 206 rounds of seventy - five and 155 - millimeter fire and an hour long engagement . North Koreans were using hidden guns which were difficult to locate but were believed to have been fired from Han - do Pan - do , Hapchin - ni and Kalamagak . Return fire destroyed three enemy gun positions and the " Thomas " was hit once , causing little damage and no casualties . On May 17 , TG - 95 . 2 reported that an interrogation of seven prisoners , captured off Ho - do Pan - do the day before , revealed that the enemy were planning an attack on Yodo in the near future . Troops are being concentrated in two locations on He - do Pan - do and are going to use about eighty fishing sampans for transport . Ten days later on May 27 , shore batteries at Wonsan fought against the USS Cabildo and " Ozbourn " . In a typical duel the American ships bombarded the coast and were not damaged , the day after USS " Ozbourn " accepted the surrender of two North Koreans soldiers . USS " O ' Bannon " suppressed enemy batteries on May 29 after the North Koreans opened fire on friendly islands . The USS " Ozbourn " , USS " Radford " , and USS " Heron " also engaged on May 29 and May 30 . " Ozbourn " received six rounds of 155 - millimeter fire and , the " Radford " , ten rounds of estimated 75 - millimeter gunfire with the nearest one landing fifty yards from the ship . The " Heron " was hit by machine gun fire that hit aft section of the vessel . There were no friendly casualties in any of the actions and in all cases the ships returned fire with naval gun s . On June 5 , the " O ' Bannon " , " Radford " and the " Lofberg " attacked and silenced a battery of 75 - millimeter guns south of Ho - do Pan - do . The artillery opened fire on some American minesweepers but quickly quieted by the escorts . North Koreans artillery in Wonsan bombarded Hwangto - do on June 7 , no casualties were reported but twenty - one shot holes were found to have passed through the flag over the island . USS " Albuquerque " was straddled by enemy fire on June 12 , wounding one man and on June 19 the North Koreans staged another artillery bombardment against friendly held Hwangto - do . USS " Parks " caught 300 enemy troops repairing a railroad , south of Wonsan on the same day , and fired twenty - eight rounds . She reported inflicting seventy - four casualties and scoring hits on a railroad bridge and tracks . When it became dark , " Parks " also fired star shells at the location for bombing runs by allied aircraft . The next exchange in the siege of Wonsan occurred a month later on August 10 , 1952 . Enemy gun positions on He - do Pan - do , fired upon USS " Barton " and USS " Jarvis " with approximately 250 75 - millimeter to 155 - millimeter guns . The " Barton " suffered superficial damage , one man killed , and one wounded . " Jarvis " was not damaged and counter battery fire destroyed two gun emplacements . Two days after , the USS " Grapple " was the target for about thirty rounds of 105 - millimeter artillery . The ship was hit once below the waterline causing slight damage . " USS Barton " fired eighty - nine shots in response and scored three hits on two North Korean batteries . The ROKN " FS - 905 " , was also attacked on May 12 . While anchored off Yo - do Island , with a cargo of gasoline and ammunition for motor torpedo boat s , ROKN " FS - 905 " was taken under fire by enemy shore guns and received one hit in the starboard machine gun battery . The damage was light and there were no casualties . Hwangto - do was bombarded again on August 16 by the North Koreans with four 155 - millimeter artillery pieces and large mortars from Kalmagak . The guns could not be located so none of the allied warships could respond . Typhoon Karen . Typhoon Karen swept through Korean waters over the next few days so also blockading activities were suspended . Several UN warships were damaged during the height of the storm . The communists used the chance to attack Hwangto - do again . After the typhoon passed USS " Lewis " fired seven rounds of 5 - inch shells at an enemy battery on Kalmagak , which was firing on friendly islands in the Wonsan area . The enemy artillery was silenced although they killed one person and wounded and two others . On September 11 , 1952 , batteries on Umi - do fired eighteen 105 - millimeter rounds at the USS " Lewis " , no damage or casualties . On September 13 , aircraft from the USS " Bon Homme Richard " attacked a 130 foot naval like vessel near Wonsan and sank it with rockets and 20 millimeter strafing . The enemy ship was one of the few sunk by UN forces during the war . Two days later , the " Barton " hit was suspected of being a floating mine while sailing 100 miles due east of Wonsan Harbor . Five enlisted men were counted missing and later presumed dead , six other men were wounded . The fire room flooded and there was other less severe damage . Flooding was brought under control and she set a course for Sasebo under her own power . USS " Cunningham " received five hits on September 19 . Guns from Wonsan , estimated to be 105 to 155 - millimeters , at a distance of 3 , 500 yards away , hit the " Cunningham " with their first shot , four more followed along with seven nearby air bursts . Eight Americans were wounded but none of them fatal and the ship was moderately damaged though she was capable of firing 159 rounds of return fire with 5 - inch and 3 - inch guns . USS " Jenkins " and USS " Taylor " came under fire from accurate shore batteries in the vicinity of Hwangto - do , the two vessels received an estimated twenty - one rounds of 90 - millimeter and three rounds of 105 - millimeter , there was no damage . North Korean forces also bombarded Hwangto - do though their batteries were silenced by thirty - nine rounds from the " Jenkins " . The North Koreans attacked Yo - do Island with artillery a few days later and on September 23 the was attacked but her 16 - inch guns quickly silenced the perpetrators . USS " Taylor " also silenced a battery on September 25 and the " Heron " received 105 - millimeter fire but was not damaged . Three splashes were counted near the ship . North Korean air attack . The first and only naval air battle at Wonsan and Hungnam occurred on October 7 . MIG - 15s attacked TF - 77 aircraft three times , one MIG made a firing pass on two American AD planes so they returned fire . There were no damage or casualties on either side and the MIGs retired to the west . Later on four MIG - 15s attacked a flight of F4Us while two others attacked eight ADs near Hungnam . In these engagements there were no casualties but in a final attack later on that day , a single MIG - 15 destroyed one of four F4Us in another action near Hungnam . On October 16 , USS " Toledo " was shot at with four rounds from estimated 75 - millimeter and 122 - millimeter guns . No damage was reported as all of the shells landed splashed in the water around 1 , 000 yards short of the ship , USS " Mansfield " was also attacked with about forty 75 - millimeter rounds . For over a month no artillery was exchanged until November 20 when the USS " Kite " and USS " Thompson " received fire from 120 - millimeter guns . The " Thompson " was hit by one round of the many which straddled her , one man suffered wounds and minor material damaged resulted . USS " Kite " fought another duel on the following day . She received fifty - five 75 - millimeter rounds but again sustained no casualties . On November 25 , the " Thomson " found herself in action , this time against enemy aircraft . Jets dropped six to eight explosives over the American ship , the closest landing 300 yards away . The aircraft were heard by the " Thompson " s lookout but radar showed nothing . USS " Merganser " was fired upon by guns at the mouth of the Namchongang River on December 6 , the " Seiverling " replied with 101 rounds , and was herself taken under fire by guns on Kalmagak . Fifty - six additional shells were then sent in that direction . On the following day , " Merganser " received thirty more rounds of 75 - millimeter fire from Kalmagak but she was not damaged . USS " Shields " , USS " Seiverling " and UN minesweepers were fired upon by approximately seventy - five rounds on December 11 . The small minesweepers were forced to slip their gear and use smoke pots to help cover themselves . That same day , USS " Waxbill " and USS " Marshall " collided west of Yo - do , " Waxbill " sustained topside damage to hull fittings but was still operational and otherwise unharmed . On December 12 the " Marshall " was attacked again , twenty rounds were fired her way but as usual the communists could not hit their target . USS " Grasp " and the " Seiverling " were also attacked and they too escaped harm . About forty rounds of North Korean artillery targeted the " Waxbill " and the " Marshall " on December 13 , while they were patrolling near the Namchongang ' s mouth . Though the fire was accurate , no hits were made . The closest shot splashed in the water ten feet from the " Waxbill " which caused shrapnel damage . Twelve shots were fired by the Americans in return . " Waxbill " came under fire again on December 19 , three rounds were fired her way but none struck the ship . A few days later , USS " Toledo " received the same treatment while bombarding the city but was not damaged either . On December 23 , while providing gunfire support for the minesweepers in Wonsan Harbor , USS " Marshall " , USS " McGowan " received approximately thirty rounds of estimated 75 - millimeter shells . During the firing , four to nine airbursts fell near the " McGowan " , sixty to seventy near " Marshall " , and several rounds between the minesweepers . Throughout the engagements the North Koreans failed to cause any damage . The " McGowan " engaged in another shore battery action two days later . Height of the Fighting . January 2 , 1953 marked the first day in a large scale North Korean bombardment of the UN held islands in Wonsan Harbor . Over the course of the next few months , enemy shore batteries in and around Wonsan fired hundreds of rounds primarily against Hwangto - do and Yo - do . The operation lasted until May and less sporadically thereafter . It was also a failure , UN intelligence estimated that ninety percent of the North Korean shore batteries were active against friendly islands rather than the blockading fleet , though throughout the bombardments , which occurred almost on a daily basis , only four friendlies were killed and fifteen wounded . During the operation , UN ships constantly responded with counter battery fire . On February 9 and February 10 , a maximum effort strike by American naval aircraft was conducted against supply concentrations and transport targets from Wonsan through Songjin to Chongjin and Hoeryong . USS " Philippine Sea " , USS " Oriskany " and USS " Kearsarge " participated in the operations which caused extensive damage to the communists logistics system . As part of the communist bombardment in the Wonsan area , enemy shells killed two men on February 14 , including an American marine , and wounded nine others in the most successful North Korean artillery attack against UN land forces . A command post on Yo - do was also damaged , one DUKN was destroyed and two other sustained damaged to their hulls . An aid station , two tents and communication wires were also damaged . Two bunkers caved in on Hwangto - do . USS " De Haven " and USS " Moore " responded with a bombardment of their own and they received fire with the nearest shells splashing 400 yards away . February 16 , was the second anniversary of the blockade . Despite that Wonsan was mostly ruins it remained a key transportation hub for communists forced , which gave UN forces the incentive for continuing blockade duties . Because of the constant threat of amphibious assault , approximately 30 , 000 North Korean soldiers and 6 , 000 civilians were pinned down and therefore could not be used at the frontline . On March 5 , during a heavy UN bombardment in Wonsan Harbor , USS " Missouri " was challenged by five rounds of 105 - millimeter shore battery fire . " Missouri " was not hit and she hastily silenced the battery . Five days later the " Missouri " received fifteen more rounds of 75 - millimeter to 155 - millimeter cannon fire while bombarding the city . The American ship escaped damage again , the nearest shot landing 500 yards off . USS " Merganser " was also engaged with the nearest shot splashing harmlessly 200 yards from her . On March 18 , 1953 , USS " Los Angeles " was carrying out bombardment duties at Wonsan when two air bursts and one surface round landed near the ship . On March 22 , during another heavy bombardment , two 90 - millimeter air bursts and two 105 - millimeter rounds landed near the " Missouri " but she was undamaged . USS " Prichett " and the " Waxbill " also received fire but no damage resulted in any of the attacks . The " Prichett " was attacked again on March 25 but no damage was sustained , USS " Shelton " , USS " Eversole " , ROKN " AMS - 502 " and " AMS - 515 " engaged in a similar action the following day . USS " Los Angeles " was hit by one enemy round on March 27 but the damage was light and no one was injured . A day later two air bursts landed 200 yards from the " Prichett " and on March 30 and March 31 , the " Prichett " evaded thirty - five more enemy shots without damage . Eight days of combined naval and air operations then started against the defenses of Wonsan . TF - 77 aircraft pounded the city but the results were negligible . On April 2 , USS " Los Angeles " received another hit by Wonsan shore batteries . This time there was only minor structural damage to the mainmast though thirteen men were injured . Fourteen others , who were wearing body armor , were also hit but not wounded . The North Korean batteries targeted naval vessels on April 5 , USS " Maddox " received six rounds of 75 - millimeter while ROKN " AMS - 515 " avoided fifty shots of 105 - millimeter fire , neither of the ships were struck . Two days later on April 7 , the communists again targeted the blockading ships but without results . USS " Los Angeles " and USS " McCord " evaded two rounds , the enemy also continued their bombardment of friendly islands off Wonsan . On April 8 , at least sixty - four shots were fired at the fleet and a couple days after , USS " Eversole " and the " Los Angeles " engaged in a duel with shore batteries . On April 16 , the " Maddox " was hit with one shot out of 156 fired at her during a forty - minute action against a ten - gun battery . The shot , a 76 - millimeter , hit port side on the main deck , tearing a sixteen inch hole and wounding three men . " Maddox " responded with counter fire but failed to silence the hostile guns . USS " Shelton " was fired at three times on April 17 . April 19 was a lively day during the Blockade of Wonsan . Twenty - five rounds from 105 - millimeter guns were fired at the " Eversole " but as was typical , the North Koreans did not strike the ship . USS " Curlew " also received three shots and another forty - one at the " New Jersey " and USS " Renshaw " . The only ship damaged in action that day was the USS " James E . Kyes " . One 155 - millimeter round , out of sixty , tore a three foot hole through the " Kyes " , wounding four men in the process , one seriously . North Korean bombardment of UN held islands . On April 22 , the North Korean bombardment of UN held islands continued , with dozens of rounds being fired each day , USS " Manchester " also sustained slight superficial damage from a battery . Between 2 : 30 and 4 : 00 pm on April 23 , the island of Tee - do was under intense enemy fire from gun positions on Kalma Pan - do . Five marines were wounded , including one American . USS " Henderson " provided counter fire while USS " Owen " took aboard the casualties . During the mission , " Henderson " and " Owen " were fired on so they withdrew and TF - 77 aircraft took over by bombing the area . On the next day , Wonsan guns fired around 100 rounds of 76 - millimeter to 105 - millimeter rounds at the USS " James C . Owens " and USS " Henderson " , no damage or casualties were reported . The " James C . Owens " was attacked on April 25 though again there was no damage sustained . On April 29 , as the bombardment of UN held island continued , a HU - 1 helicopter received fourteen rounds of VT fuze d enemy shells while on a mine reconnaissance flight over Wonsan Harbor . The aircraft was not damaged but the encounter told the Americans that another new type of weapon was being used by North Korean forces . USS " Gurke " also avoided six enemy shells that day . April 1953 was reported by the United States Navy as being the height of the three - year battle with enemy forces firing over 2 , 000 artillery rounds in defiance of the blockade alone , and over 1 , 000 more at the friendly guerrilla held islands . Usually the was average was about 500 rounds a month . North Koreans troops also constructed hidden batteries on Ho - do Pan - do , the Americans bombarded them with 5 - inch guns without effect . Because of this , UN naval forces were ordered to stay out of the area in daylight until the weapons could be destroyed by cruisers and battleships or naval aircraft . Mine warfare also increased during the month of April , after months of finding nothing , thirty - two new mines were found in Wonsan Harbor . On May 2 the hidden guns made two hits and two near misses each on the USS " Maddox " and USS " Owen " , both ships received slight damage and there were no casualties . Over two hundred shells were fired by the enemy . The " Gurke " came under fire on the following day , along with the friendly islands of Wonsan Harbor . USS " Bremerton " engaged in a heavy gun strike against enemy batteries eighteen rounds of 76 - millimeter to 105 - millimeter shells flew by . One near miss minorly wounded two men and the ship received superficial damage topside . USS " Samuel N . Moore " was hit by a 90 - millimeter shell on May 8 but it did no significant damage . The round starboard side just above the waterline . The same battery fired at USS " Brush " , sixty - four total . Allied air strike against Yo - do island . On May 15 , TF - 77 aircraft attacked an airfield on Yo - do island while American ships silenced the batteries on the islands . USS " Brush " was also hit in the mount that day , making it inoperable , and nine men were wounded , four seriously . The battleship " New Jersey " was fired at on May 27 but her 16 - inch guns quickly put an end to it , meanwhile the islands were still receiving their daily barrage which continued in June . heavy gun strikes also continued , the communists resisted every UN attack but very few hits were made . On June 3 , Wonsan shore batteries fifteen 105 - millimeter shells at the USS " John A . Bole " and USS " Lofberg " but no damage occurred . The guns were silenced by return fire . USS " LSMR - 409 " was hit on June 4 , causing moderate damage to the messing compartment and the radio room , and resulting in five men wounded . The enemy fired thirty rounds of 76 - millimeter fire before being silenced by over 200 rockets from the LSMR . USS " PC - 706 " destroyed five North Korean fishing boats on the beach at the northern end of Ho - do Pan - do . The weather was very foggy and sure enough Typhoon Judy was announced the following morning which hampered TF - 77 ' s operations for three days . The " Lofberg " and the " John A . Bole " were attacked on June 8 by batteries but it was another inconclusive contact . " Bole " spent the next day bombarding enemy guns . On June 11 , the USS " Wiltsie " received an estimated forty - five rounds of 105 - millimeter fire . The vessel was hit one time on the starboard side of her main deck but was still completely operational . Shrapnel caused a lot of damage and a four - inch hole in the deck . No casualties were inflicted on American forces . Three days after this incident the USS " Bremerton " , USS " Lofberg " and USS " John A . Bole " exchanged fire with the batteries , several guns were destroyed and there were no friendly casualties . The " Lofberg " , the " Bole " and the USS " Current " received 110 rounds of fire on the next day without effect . Shore batteries on Ho - do Pan - do were increasingly menacing the allied blockade , concentrated fire was directed against destroyers in Wonsan Harbor on June 17 . USS " Irwin " and USS " Rowan " re - escaped to seventy - five founds and the " Henderson " avoided another seventy - five , the nearest landing ten yards from the " Henderson " . The " Irwin " and the " Rowan " would fight another battle the following day . In it the North Koreans scored their most number of hits in one engagement . USS " Irwin " was hit by one round from Kalmagak and it tore a three foot hole in the main deck . Five American sailors were wounded . The " Rowan " suffered five hits and ten casualties , none of them fatal , and she received forty - five rounds of different caliber altogether . The destroyer was moderately damaged . Thirty - six shells were fired at the " Saint Paul " but she was not hit . A small surface engagement occurred the same day . An armed South Korean Army intelligence boat encountered a North Korean thirty foot patrol boat and for ten minutes the vessels fought until the North Koreans withdrew under cover of a battery . The patrol boat had a speed of twenty knots , carried a radio and was armed with rocket launchers , machine guns and the crew carried various small arms . On June 19 the " Rowan " and the " Bremerton " were fired on but no hits resulted . USS " Manchester " was conducting a heavy bombardment of Wonsan on or about July 3 when fragments from a near miss put a two inch hole in the after stack and through the door of a powder room , no one was hurt though . On July 7 , enemy gunners on Ho - do Pan - do concentrated their on the blockade . Over 300 rounds of 76 - millimeter to 122 - millimeter fire landed near the USS " Lofberg " , USS " Thomason " and USS " Hamner " . Thomason suffered holes and dents topside due to air burst straddles but there were no casualties . The Americans returned 880 rounds of counter battery fire before the action ended . A few days after , enemy artillery fired forty - eight rounds of 76 - millimeter to 105 - millimeter shells at USS " Saint Paul " and scored a hit on a gun mount . Two guns were damaged but nobody was wounded . For the next several days the North Koreans focused on attacking friendly islands until July 23 when the " Saint Paul " drew twelve rounds of 155 - millimeter fire and all of the shots splashed in the water ten to fifty yards from the ship . On July 27 the " Saint Paul " fired the last American shots of the battle against shore batteries . With the signing of an armistice , the fighting came to an end after 861 days of action . Aftermath . United Nations ships at Wonsan achieved a significant goal by maintaining a blockade against hostile territory for so long . UN naval forces inflicted heavy casualties on the North Korean forces while sustaining comparatively few casualties of their own . The North Korean artillerymen who defended Wonsan were mostly ineffective , thousands of dollars worth of artillery shells were wasted . Wonsan was destroyed and remained so for years after the war , but due to its location , it was eventually rebuilt and is still an important strategic point .