"Military Sub-Plane" by: Armored Shovel Historian
Opening the road in every mountain and building bridges in the face of water is probably the most intuitive understanding of the sappers, but on the battlefield, it is often the combat branches such as infantry, artillery, and armored troops that are more concerned, and the public lacks understanding of the auxiliary arms such as engineers. As everyone knows, for mechanized troops, high-quality professional sappers have long become an indispensable part, and in some battles, engineers often play a key role in determining victory or defeat and even the survival of the troops.
In the Battle of Chosin Lake on the Eastern Front of the Second Campaign of the War to Resist US Aggression and Aid Korea, the US engineers and transport aviation units jointly acted as the "key sir" in saving the US First Marine Division, and repaired the crucial Watergate Bridge in time, thus ensuring that the US Army was freed from the encirclement and blockade of the volunteer army, providing an excellent example of the combat effectiveness of modern engineers.
▲The photos taken by the U.S. military at the site of the Watergate Bridge in early December 1950 show that the gap on the south side of the bridge and the surrounding terrain can be observed.
The Road to Escape to the South
In the first stage of the Chosin Lake Campaign, the Volunteer Army divided the main force of the 1st Marine Division and the 31st Regimental Combat Team of the 7th Army Division into isolated strongholds around Chosin Lake, such as Liutan-ri, Xinxing-ri, Hagasu-ri, and Koturi, but due to insufficient manpower and firepower, they failed to annihilate it, and in addition to severely damaging the U.S. troops in Xinxingli, they failed to prevent the U.S. troops from breaking through and retreating south. By 7 December, the main force and remnants of the 1st Marine Division had all retreated to Gutuli, and the next plan was to return to Zhenxingli via a 16-kilometer rugged mountain road, where Major General Oliver Smith, commander of the 1st Marine Division, had a reinforced battalion to protect the supply line. From Zhenxingli further south to Xianxing, the terrain is gradually relaxed, which is convenient for the mechanization of the US army, and will be received by the Army's 3rd Division, so as long as it withdraws to Zhenxingli, the American army can leave the mountainous area and escape the encirclement of the volunteer army, but there is a fatal node in the last section of the retreat road, that is, the Watergate Bridge.
▲ 1:50,000 map from Kotoori to Zhenxingli. This is a 1951 map that is very similar to the Japanese map used in 1950, showing the complex topography of the mountainous area with a 20-meter contour.
Smith later wrote in his memoirs: "At this point (the Pratunam Bridge), water from the Chosin Lake Reservoir through a tunnel emerged from one side of the mountain and was discharged into four large concrete pipes that plummeted along the mountainside into the turbines of the hydroelectric power plant in the valley below." At the intersection of the pipeline and the highway, there is a concrete substation, without a floor, located on the uphill side of the road, covered above the pipe. On the downhill side of the substation is a single-lane concrete bridge. The mountain drop here is very large, and there is no possibility of detour. The bridge was so vital to us that we could not bring out vehicles, tanks and other heavy equipment without it. ”
On December 8, nearly 1,500 U.S. tanks, vehicles, and artillery in Ancient Tuli awaited their retreat south through The Watergate Bridge.
▲ The panorama of the Watergate Bridge taken by the US military from a light reconnaissance plane shows the substation and water pipeline, and you can see that the mountain here is very steep.
Smith could see the importance of the Watergate Bridge, and the commander of the battle-hardened 9th Corps of the Volunteer Army, Song Shilun, was even more impressed, and he ordered the 58th and 60th Divisions of the 20th Army, which were responsible for the detours, to destroy the road, blow up the bridge, and block the American army. The 180th Regiment of the 60th Division, which had penetrated to the southernmost flank, had already set its sights on the Watergate Bridge, blowing it up for the first time on December 1, but the American sappers built a wooden bridge and restored traffic.
The 180th Volunteer Regiment continued its efforts and again destroyed the bridge on December 4, and the 58th Bridge Company of the US Army repaired the broken bridge for the second time using the only M2 steel rutted bridge component. On 6 December, the 180th Regiment did its utmost to organize commandos to destroy the Watergate Bridge for the third time, blowing up a gap of more than 5 meters wide on the south side of the bridge, and the volunteers expected that the Americans would not be able to repair it in the short term. However, the U.S. military's battlefield engineering capabilities far exceeded the scope of Chinese soldiers' understanding at that time.
On December 9, 1950, U.S. Marine Corps soldiers inspected the blown-up Watergate Bridge. If it can't be repaired here, the heavy equipment of the US military will not be able to be withdrawn.
The fate of the 1st Marine Division was now in the hands of the American Engineer Corps. In addition to the engineer battalion directly under the division, each regiment of the 1st Marine Division is also equipped with a combat engineer company, in addition to the Army's 185th Engineer Battalion, which began to build an airstrip on December 3 and was put into use on December 6 for the evacuation of the wounded.
A platoon of the 58th Bridge Company and the 512th Dump Truck Company were also in The Ancient Soil, and their original mission was to transport building materials for the construction of the forward headquarters of the 10th Army in Hagaru- The 58th Bridge, which originally belonged directly to the 10th Army, built a pontoon bridge over the Nakdong River after the Inchon landings, and was assigned to the 1st Marine Division to Go North to Chosin Lake in November 1950, and the company had four Brockway bridge trucks with a load of 6 tons, two of which could be used, and they could load heavy rutted bridge components and hoist them where they were needed.
▲ In April 1945, the 1139th bridge company of the US military built a pontoon bridge on the Danube River south of Regensburg, Germany, and the road on the bridge was paved with M2 rutted bridge components.
The rutted bridge is a multi-section steel bridge component developed by the US military, consisting of two tracks and a middle pedal, and two rutted bridge components are placed side by side to form a road.
The U.S. M2 rutted bridge was originally designed as a pontoon component and fixed to the pontoon, but it can also be built with a land bridge for artillery, heavy trucks and tanks to pass. However, the 58th bridge has already consumed all the rutted bridge components it carries, and in the ancient soil there are only bridge trucks, but no bridge building materials.
Skyfall steel bridge
The U.S. Army Engineering Unit in Gutori was uniformly commanded by Lieutenant Colonel John Partridge, commander of the Engineer Division of the First Marine Division, who and Commander Smith began planning countermeasures when the Volunteers first attacked the Watergate Bridge.
On December 6, Partridge personally conducted aerial reconnaissance of the Watergate Bridge, and through visual inspection, he judged that it would take 4 rutted bridge components to repair the gap in the broken bridge, so he proposed a bold idea to the division commander: he asked the Air Force to urgently airdrop the required rutted bridge components into the ancient soil, the problem was that each bridge component was 5.5 meters long and weighed 1.3 tons, which had never been done before in the history of war!
Smith was suspicious of Partridge's proposal and repeatedly asked for details of the operation, saying in his memoirs that Partritch was "annoyed by the cross-examination, and finally he broke out and said angrily: 'I let you cross the Han River, I built you an airport, and of course I will build you a bridge!'" Smith then made this particular request to the U.S. Air Force's Far East Combat Cargo Command.
In January 1951, Smith, commander of the First Marine Division, shook hands with Lieutenant Colonel Partridge, commander of the division's engineers, who received a second Bronze Star Medal for his outstanding performance at the Battle of Chosin Lake.
Partridge and George Barber, commander of the Engineer Battalion of the First Marine Division, and Hugh McGough, commander of the 185th Engineer Battalion, conducted the study, and although only 4 components were needed, they were on the safe side and they asked the Air Force to airdrop 8 components.
The U.S. Air Force reacted positively to the front-line demands, urgently transferring bridge components from Japan and arranging for airdrops. The 61st Transport Squadron of the U.S. Air Force's 314th Air Transport Wing at Ashiya Base in Japan was responsible for this task, sending C-119 transport aircraft to Tachikawa Airport near Tokyo to transport the prepared bridge components back to Ashiya and then to Eipo Airport near Konan Port.
The Fairchild C-119 transport aircraft was developed from the C-82 transport aircraft, first flew in 1947, and had delivered 1183 by the time it was discontinued in 1955, known as the "Flying Stuffy Tank Truck" because of its peculiar shape and unusual loading capacity, and was one of the best twin-engine medium transport aircraft in the world at that time.
In the 1950s, a U.S. Air Force C-119 transport aircraft in flight.
To test the feasibility of airdropping, Squadron 61 conducted a test launch at Eipo Airport, fixing six G-1 cargo parachutes with a diameter of 7.32 meters on a bridge component, and the aircraft was launched from an altitude of 240 meters at a speed of 140 knots (260 km/ h).
The results were disappointing, with 5 of the 6 parachutes not being opened and the 6th not fully opening, and the bridge components smashed into the ground like stones, causing irreparable damage. After inspection, the rigger believed that the reason for the failure was that the parachute ropes were entangled and pulled on each other to break. Cecil Horspehorn, commander of the Army's 2348th Quartermaster Airborne Supply Packing Company, suggested replacing six small parachutes with 2 G-5 cargo parachutes with a diameter of 14.64 meters.
Due to the tight time, it is no longer possible to try to invest, so it has to go directly to the horse, and the success or failure depends on luck. The 2348th Company and 100 men from the 1st Amphibious Tow Battalion were busy all night connecting the G-5 parachutes urgently shipped from Japan to bridge components and loading them into the cargo hold of the C-119.
On December 7, 1950, over Gutuli, an M2 rutted bridge section was sliding out of the tail of the C-119 transport aircraft of the 61st Squadron of the Airlift Wing of the 314th Unit. The rear mussel shell hatches of the C-119 have been removed to accommodate the extra-long bridge components.
On the morning of December 7, eight C-119s of the 61st Squadron, each carrying a bridge component, took off from Eiura Airport to Gutuli at a five-minute interval, and the mussel shell hatches in the tail of the aircraft were removed due to the length of the cargo and the convenience of delivery.
At 9:30 a.m., the first aircraft arrived in target airspace, reduced the flight altitude to 240 m, slowed down to 120 knots (220 km/h), and entered the airdrop route along the valley, at which point the plane was already below the surrounding peaks. In order to avoid accidental injury, the US military demarcated two airdrop zones on the outskirts of Gutuli, one 1 km to the north and one 1.6 km to the southwest, each of which was about 300 meters long. When the C-119 flew over the airdrop area, the pilot refueled and pulled up, and while the nose was tilted, the cargo hold personnel cut the fixed cable of the bridge component, causing it to slide out of the cargo compartment under gravity and land with an umbrella. Three aircraft chose the north side of the airdrop area, the other 5 unloaded on the south side, during which they were attacked from time to time by small arms from the ground, some of which were injured, and volunteers who lacked anti-aircraft weapons could only look up at the sky and sigh as they watched the American planes fly by.
The first 5 aircraft successfully dropped components, but the 6th component deviated from the target and fell into the Volunteer position, while the 7th component failed to land and was damaged, the last C-119 made a mistake in the first time through the airdrop area, the components failed to get out of the cabin, and could only risk hitting the mountain to make a 180-degree turn to launch again, and the US military finally recovered 6 complete components, and the bridge program was half completed.
Each airdropted rutted bridge assembly is slowed down by two G-5 large cargo parachutes with a diameter of 14.64 meters.
Firewire bridge
The Air Force had finished their work, and the rest was up to the sappers. Charles Ward, the bridge platoon commander of the 58th Bridge Company, and his soldiers loaded the recycled bridge section onto the Brockway Bridge truck and waited for the order to go to Watergate Bridge. On the night of December 7, clouds enveloped the land, a snowstorm swept across the battlefield, the temperature dropped to minus 35 degrees, and until December 8, the sky was still snowing heavily, and the visibility was only 15 meters, meaning that the U.S. troops could not get air cover.
The U.S. troops in the ancient soil began to continue to break through to the south against the wind and snow, alternating cover to open the escape channel. The bridge trucks that followed the infantry forward once drove near the Watergate Bridge, but due to the efforts of the volunteers, the safety of the bridge construction operation could not be guaranteed, and the US army had to let the valuable bridge trucks return to Gutuli and wait for the next day to build the bridge.
▲ The picture may be the Brockway Bridge Truck of the 989th Bridge Company of the US Army during World War II.
On December 9, the sky was clear but cold, and the roar of American aircraft once again echoed in the deep valleys. Partritch ordered Worm Ord of Company D of the Engineer Battalion of the First Marine Division to lead a platoon of engineers to Watergate Bridge to prepare for construction. The sappers arrived at the bridge site under heavy escort and accidentally found that the gap in the bridge was larger than Partridge estimated, and the existing bridge section was more than 2 meters worse and lacked support.
Fortunately, the Marine Sappers had prepared for it, and a truckload of pre-cut wood that had been stolen from a sawmill in Xinxingli was now handy. Later, in an interview at his home in Reno, Nevada, 81, Ord recalled: "[At the time] considering we might need these things, I asked the sappers to tow away a truckload of wood... We always stole everything we could and no one paid. ”
The sappers unloaded the lumber and set about erecting a pedestal at the broken bridgehead. They alternately stacked the wood and filled the gap in the middle with sandbags to make the abutment "look strong."
Schematic diagram of a steel rutted bridge assembly with pedal spacing hook, pedal connection pin and safety device.
At noon on December 9, Lieutenant General Almond, commander of the US 10th Army, flew over the Watergate Bridge in his own "Blue Goose" plane and witnessed the tense construction of the sappers, and everything seemed to be going smoothly.
At noon, 2 bridge trucks transported the bridge section to the Watergate Bridge, due to the narrow road, there was no room for vehicles to turn around, they could only turn the front of the car in the appropriate section, and then after guiding the next way back to the bridge, the rutted bridge components were placed in the gap.
The Army and Marine Corps engineers worked together to assemble four sections of the bridge in three hours, two on each side, parallel to each other, to restore the watergate bridge to vehicle traffic. At 15:30, Partridge informed the division headquarters of the bridge repair, and the American vehicles lined up in groups of snakes and snaked along the mountain road, and the first American vehicle passed through the Watergate Bridge at 18:00 and headed south, arriving at Zhenxingli at 2:45 a.m. on December 10, and the gate to Xianxing was finally completely opened.
A U.S. military truck is carefully passing through the rutted bridge at the gap in the Watergate Bridge.
Rushing traffic
From the afternoon of December 9 to noon on December 11, the marching column of tens of thousands of horses and horses of the First Marine Division and more than a thousand vehicles continued to squirm on the mountain road from Gutuli to Zhenxingli, during which there was only one brief pause.
Although the steel girder part of the rutted bridge can withstand a weight of 50 tons, the middle bridge plate has a load of only 20 tons, which is enough for most vehicles, but there was an accident, a tractor dragging an excavator collapsed a bridge plate, and two cars hung on the bridge in a precarious position.
Marine Sapper Wilfred Prosso, an expert tractor driver, climbed into the tractor and carefully pushed the trapped vehicle off the bridge. The current situation is that the bridge deck has a loophole, and the tank can continue to pass through the steel beam, but there are difficult obstacles for other vehicles with narrow wheelbases to overcome.
▲ American infantry and vehicles retreated through the Watergate Bridge to Zhenxingli.
Patrician immediately organized manpower to carry out emergency repairs, pulling the two columns of bridge sections as far apart as possible, so that the total width of the bridge deck reached 4 meters, so that all vehicles could cross the bridge along the steel beams, for the tracks of the M26 "Pershing" tank, there was a margin of about 5 centimeters, and the jeep with the narrowest wheel gauge could fall off the steel beam as long as it was deviated by 1 centimeter, and now it was time to test the driving skills of the American driver.
After nightfall, in order to avoid the sneak attack of the volunteer army, the US military vehicles can only turn on the "cat's eye" headlights with the lowest illumination, so when crossing the bridge, the driver basically cannot see the steel beams on the bridge, and can only rely on the flashlights of the sappers to guide through, just like the "bilateral bridge" test of driving school in the dark.
The retreating columns were organized 400 meters apart and vehicles 50 meters apart, so as not to lose too much in the event of a surprise attack or precise fire. On both sides of the road, infantry moving along the ridge provided cover for the vehicles, and 40 tanks from the Marines and Army, accompanied by a reconnaissance company in jeeps, pressed at the end of the column, on the one hand to prevent the volunteers from trailing pursuit, and on the other hand, to prevent these heavy big guys from breaking anchor halfway and blocking the road. The US column did not stop at the revitalization and retreated to Xianxing without stopping.
The M4A3 Sherman tanks of the 1st Tank Battalion of the First Marine Division waited in the snow for news of their southward movement.
It is worth noting that the entire retreat of the US military from Gutuli to Zhenxingli was strongly covered by air and ground fire.
The U.S. 155 mm howitzer deployed in Zhenxingli can shoot shells directly into the ancient soil, and the peaks on both sides of the road are within range of the U.S. artillery, as long as there are good traffic conditions, the retreating U.S. troops can get artillery support at any time. At the same time, whenever weather conditions permitted, the 1st Marine Corps Air Wing maintained 24 aircraft over the retreating troops during the day to provide immediate fire support, and at night it would also dispatch night fighters to maintain a certain air deterrent. The Marine Corps Air Force sent senior personnel to serve as air-ground guides to accompany the ground troops, and each battalion of the First Marine Division was equipped with 2 guides to guide the targets of the air fighters at any time, and the instructors commanded the air support within 3.2 kilometers of the troops.
In addition, the U.S. military can also be supported by naval aircraft carrier aircraft outside the port of Konan, as well as air force aircraft from Eipo Airport and even Japan's Itami Air Base.
▲ On December 10, 1950, the 155 mm self-propelled howitzer of the Doug Task Force of the 3rd Division of the United States Army was in a firing position at the mountain pass near Zhenxingli.
Just after midnight on December 11, after the last tank and reconnaissance company vehicle passed through the Watergate Bridge, the U.S. Army completely blew up the Watergate Bridge to avoid a pursuit by volunteers.
Partritch later recalled: "When everyone passed, I blew up the bridge and finally grew a breath. At 3 a.m., the U.S. troops guarding Hill 1081 south of the bridge received orders to retreat.
At 13:00 p.m., the last U.S. troops left Zhenxingli. At 21:30 p.m., all the U.S. troops retreating from the Chosin Lake area arrived at the assembly area near Hamhung, and the "miraculous turn" of the 1st Marine Division came to an end.
Tanks and infantry of the 1st Marine Division retreated along the snow-covered road towards Hamhung.
epilogue
In the Battle of Chosin Lake, the US military repaired the Watergate Bridge three times, especially the last airdrop component and the fire line bridge can be regarded as a major highlight, and as far as the US military is concerned, it is also a super-conventional operation, showing the flexible response ability and strong battlefield support capabilities of the US military as a modern army.
Of course, the role of the US engineers was not limited to repairing the Watergate Bridge, in fact, throughout the course of the campaign to provide close support to the combat troops, such as in order to let the 40-ton M26 "Pershing" tank and 5 large bulldozers drive to Hagaru-ri, the engineers began to widen the road from November 16, and it was basically completed on November 19. The greatest achievement of the American engineers in this campaign was the construction of a field airfield of about 900 meters long and capable of taking off and landing transport aircraft in Hagaru in 13 days, the last four days of which were completed after the battle was completed by the artillery fire of the Volunteer Army, in addition to the construction of a 525-meter-long improvised runway in the ancient soil.
These two front-line airfields were not only conducive to the airlift of supplies and equipment, but also sent more than 5,000 wounded by air before the breakthrough of the First Marine Division, which greatly reduced the burden of the WITHDRAWAL of the US army and reduced the number of personnel losses. It can be said that without the outstanding performance of the US engineers, even if the First Marine Division could escape the encirclement of the volunteers, its losses would have increased significantly, and it would most likely be forced to abandon all heavy equipment and seriously wounded.
▲ On the road known as the "Valley of Hellfire" between Hagaru-ri and Kotori, vehicles destroyed by the 60th Division of the 20th Army of the Volunteer Army, which was responsible for blocking, were pushed to the side of the road by Us engineers.
This contest between the three bombings of the Watergate Bridge by the Volunteer Army and the three repairs of the Watergate Bridge by the US Military has made China realize what is the steel industry, and also let the United States see what is the will of steel. After the War to Resist US Aggression and Aid Korea, China began to vigorously develop industry and gradually improved its industrial system over the course of several decades.