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W ith pierced steel planking you couldhave a runway where you needed one.Even the holes in it were functional.

Marston MatBY RICHARD K SMITH

T WAS ten feet long, fifteen inchesI wide, covering 12.5 square feetwith a surface resembling Swisscheese stamped out of steel, and itweighe d 66.2 pounds. Locked to-gether, 60,000 of them created a du-rable all-weather surface 5,000 feetlong and 150 fee t wide that routinelyaccepted punishment from air-planes weighing up to 60,000pounds thumping down at speeds ofninety miles an ho ur. This is the ma-terial that provided the quickly b uiltpla tforms from wh ich Ame ricancombat aviation was projectedaround the wo rld during W orld War

During 1941-45, the material wasgenerally known as M arston mat.This led many to believe that it wasinvented by som eone named M ar-ston. Or may be it was a British in-vention, m anufactured near Mar-s ton M oor , England. The t ruth i smore prosaic. The name comesfrom a whistle-stop on the SeaboardCoast Line Railway, thirty-fivemiles west of Fo rt Bragg, N. C.Here on a low hill a mile east ofUS Route 1 and two miles northeastof M arston, N . C., the material wasfirst put to practical use. Th at was

during the Army 's Carolina M aneu-vers of Novem ber 1941, just beforePearl Harbor. Th e no vel s tee l matgave an em inently satisfactory per-formanceone fraught with epochal consequences.Gen. H. H. Hap Arnold, Chiefof the Arm y Air Forces, visi ted theM arston strip and hailed it as theyear's greatest achievement in avia-tion.Th e M arston strip, 150 feet by3,000 feet, was operational for onlya few weeks. W hen the m aneuversended, the runway was dismantled,loaded into e ighteen rail road gon-dola cars, and hauled away to Lang-ley Field, Va.taking with i t thename of Marston. Thus, theM arston strip, as i t was called,entered Army vernacular , and themater ia l became known as M ar-ston m at.Years later , when mem ories o fW orld W ar II had faded and acro-nyms took charge of military vocab-ularies, the village of M arston losti ts claim to fame as bureaucrats re-duced the material s name toPSP pierced s teel planking. Aquarter of a cen tury after 1945, thegeneration that laid hundreds of

By itself it s not much (right), but stick afew together and you have a welldrained, dust- and mu d-controlling,Instant runway capable of supportingheavy bom bers. This versatile materialbecame the footprint of Allied airpowerin World War

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Marston mat s compact dimensions and relatively light weight made it easy to shipand to carry Wired into bundles and subbundies, 375 square feet of runway surfacestood only twenty eight inches high. Tivo men could pick up a piece and run with it.Here, a Guadalcanal airfield is improved with Marston mat after the island s capturefrom the Japanese.

thousands of tons of M arston m atthroughout South V ietnam had noidea who or what M arston m ighthave b een or that a Marston existed.The material was simply PSP .Anglo French InspirationIn the spring of 1939, the ArmyAir C orps took note of operations inBritain and France where air forceswere experimenting with steel gridsfor unimproved airfields. U nlike thesituation in the United S tates, onthe eve of W orld War II there werefew concrete runways among Euro-pean airpo rts, but their turf airfieldswere among the best in the world.They were carefully sited, well tiledfor drainage, often having collectingpoints and pumping stations in-stalled, and were carefully plantedwith various spec ies of grass whoseroot systems absorbed m oisture.Howev er, this was a technology notsusceptible to rapid improvement.W ith war imm inent, the Anglo-French air forces required hundredsof airfields for dispersal, and the ca-sual pastoral expedients of W orldWar I could not serve airplaneweights of 1939. A Sopw ith Camelfighter of 1918 weighed 1 950pounds a Hawker Hurricane of1939, 6,600. Furthermore, unlikethe flying machines of 1918 , the air-planes of 1939 had brakes. N othingtears up an airfield's turf like the

frequent use of brakes by heavy air-planes.British runway mat was similar toheavy-duty chicken wire. Shippedin huge rolls weigh ing tons, it wasdifficult to handle. O nce in p lace, itwas difficult to repair, and it seemedinadequate for medium bomb ers.The m ore versatile French type wasa heavy steel chevron gridwork sim-ilar to that used in bridge deck s orindustrial catwalks. B ut each sec-tion weighed more than a hundredpounds, installation was com plex,and much of the runway had to betaken ap art to repair just one sec-tion.The Air Corps required something more v ersatile, much lighter,and given to mob ility. The specifica-tion is summ ed up b y an old sayingof the American aircraft industry:Simplicate and add a bit of light-ness.In 1939, the gross takeoff weightof a typ ical single-engine f ighterplane was 7,000 pounds; a mediumbom ber weighed 35,000 pounds.But the Air C orps required a surfacealso capab le of supporting 55,000-pound heavy b omb ers, such as theBoeing B -17 Flying F ortress or theC onsolidated B-24 L iberator. Fur-thermore, in 1939 the Air C orps wasalready getting ready for bom berslike the B-29 S uperfortress weigh-ing more than 125,000 pounds.

Adaptable to Global LogisticsBesides being ab le to support air-planes, the mat had to occ upy m ini-mum space for ocean shipment.This was of small consequence toEuropeans, but everywhere Ameri-cans looked they w ere standing onthe water's edge.One piece of M arston mat fit neat-ly inside another; a bu ndle of thirtypieces stood less than twenty-eightinches high. Packed for shipping,the mat for a 150-foot by 5,000-footrunway weighed 1,986 tons and oc-cupied 41,600 cubic feet. T he lowerhold of #3 hatch, the largest spacein W orld W ar II's ubiquitous Liber-ty ship, had a bale capacity of 59,793cubic feet.Distinct from its cubic dim en-sions, the weight of this single run-way constituted twenty-one percentof a Liberty ship's payload. The ma-terial was distributed am ong a ship'slower holds, like flooring. Bulkierand lighter cargoes were loaded ontop of it. With comb at loading, suchlow-density i tems as b ul ldozers,graders, trucks, rollers, and othervehicles were needed first; the high-density runway mat was the last ma-terial required.For shipping and convenience inthe field, five mats were wired intosubbundles; six of these were b and-ed into a full bundle. Each full bun-dle contained twenty-nine full-length mats and two half-lengths--atotal of 375 square feet. With themats laid in staggered brickwo rkfashion, the half-lengths were usedto piece out the edges of a runway.The m aterial also had to be easyfor its installers to handle. Installa-tion had to be simple even indarkness. The Air F orce specified amaterial of no more than sevenpounds p er square foot; Marstonmat was 5.3 pound s. Its unit weightwas 66.2 pounds. One man couldhandle a section with ease; two mencould pick up a p iece and run withit. As a rule, the only tool necessaryfor its installation was a sledg e tobea t it into the earth.As inventions go, Marston matranks among the simplest. Althoughits function was to serve motion, ithad no mov ing parts. A single matconsisted of a steel sheet with tworibs dividing its length into three flatchannels. Each channel had twenty-nine holes punched along its length eighty-seven holes per mat. The

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Marston mat s simple design facilitated easy repair as well as easy installation.Locked together by a hook-and-slot design, beaten into the earth with sledgehammers and secured by steel spring clips sections of runway could be removedwith a pry bar. Here, troops repair bomb-damaged portions of Henderson Field,Guadalcanal.

holes were flared to increase them at s rigidity.These holes not only contributedto strength and reduced weight butalso helped a section adhere to theearth. The ho les also served drain-age and helped dry ou t the terrainon which the m at rested. V egetationcould grow through the holes, re-ducing the problem of dust and mak -ing a sm all contribution to camou -flage. The holes also m ade it possi-ble for back fill to be poured intosm all soft spots in the earth.A long each edge of a m at s lengthwere thirty slots and thirty L-shaped hooks cut and bent from themat's edges. Having hooks andholes in each mat m ade the matsinterchangeable. The hooks of onem at were dropped through the slotsof the adjacent mat, and thenshoved forward two inches, lockingthe hook into the slot. Mats w erefurther locked together by easily re-m oved U -shaped steel spring clipsthat lim ited vertical m otion.For ease of removing a dam agedm at, it was practice to install onecourse of m at with its hooks p ointedin one direction, and the next coursewith its hooks pointed in the other.W hen a runway was com plete, a sin-gle m at could be rem oved by twom en with pry bars.

esign and ManufactureThe M arston m at owes its designto Gerald G. Greu lich of the Car-negie Illinois Steel Co. and to m anycontributions by the Arm y Corps ofEngineers. When first tested atLangley F ield, V a., in the summ erof 194 0, the ribbed steel plank wassolid sheet. Later, buttons werepressed into the flat channels tocreate a nonskid surface, but theydidn t seem to m ake m uch differ-ence. During the winter of 1940-41,it was decided that a solid surfacewas unn ecessary, and holes werepunched along the channels, givingthe m at its distinctive appearanceand reducing unit weight by 1 7.5percent.There were five steps in its man-ufacture: (1) the long itudinal ribswere p ressed or cold-rolled into ablank sheet of 10-gaug e low-carbonsteel; (2) the slots and hook s werepunched out; 3) the holes werepunched and flared; (4) the hookswere bent ninety degrees to the mat;and (5) the m at was cleaned, de-

greased, and painted. B y D ecemb er1941, two factories had alreadymanufactured some four millionsquare feet of the m aterial. A y earlater, twenty-nine factories wereproducing Marston mat.A t the dawn of 1944 , m ore than180,000,000 square feet (some477,000 tons) had been shippedoverseas. This was enough for 240runways 150 by 5,000 feet. By theend of the war, almost two m illiontons had been produced, represent-ing enough steel to build 600 L iber-ty ships.Sooner or later it is GeneralMud who commands too manybattle situations. Mud does not oc-cur in nature when rain only wetsthe earth; but g iven intensive use byheavy airplanes and a week of rain,the best turf airfield will degenerateinto a crazy-quilt of badly ruttedm ud. Marston m at performed wellon soft ground, overcoming most ofthe problems.Sim ilarly, Marston m at controlleddust. T he airplane is an incorrigibledust m aker, and on a bu sy airfielddust can be an op erational night-mare. Dust ingested by enginesshortens the time between over-hauls never m ind the general wearand tear on an airp lane and its inte-rior parts.In du sty N orth A frica, airplaneeng ines had only half the life be-

tween overhauls compared withthose operated from the w ell-pre-pared airfields of England. M orefrequent overhauls require morespare parts, m ore m anpower, andm ore facilities to serve the work . InNorth A frica, the total increase inlogistics requirements often be-cam e horrendous. Meanwhile, air-craft availability suffered.D ust also creates operational andtactical hazards. A fter two or threeairplanes take off from an arid, dirtrunway, visibility is reduced tozero. Since airplanes take off intothe wind, the dust they generateblows back am ong the planes wait-ing to take off. W ith each takeoff thedust becomes thicker. Precious min-utes are lost before the next p lanecan get into the air.

In the worst conditions, it couldtake half an hour to get a squadronoff the ground, an op eration thatnormally took five minutes. Tanktrucks sprayed w ater over the run-way to hold down dust, but this cre-ated only a thin patina that evapo-rated quick ly. T he pressure of air-plane tires broke the thin crust, andprop blasts blew away what re-mained.Each hole in a piece of M arstonm at provided a sm all reservoir forrunway watering, retaining itsmoisture for fifteen minutes orm ore. It was soon discovered that if

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This Marine Corps photo from World War II shows an AAF B 17 Flying Fortress restingsecurely on a Marston mat runway on Guadalcanal. Basically unchanged sometwenty five years later, the material became known as PSP, for pierced steelplanking, and hundreds of thousands of tons of it were laid throughout SouthVietnam to support far heavier aircraft.you covered the runway area w ithlocal floraleaves, sm all branches,palm fronds, or, if it could be found,hay and laid the mat on top, yougreatly reduced the dust problem .Even after these materials driedout, they m aintained b arriers be-tween the m at and the dust, retain-ing hygroscopic qualities that maderunway w atering m ore effective.After experience w as gained, itwas not unusual to have an areacleared and graded, the m at down,and airplanes operating within sev-enty-two hours. Creating an ele-vated subgrade was desirable andoften necessary before laying them at, although it added a few days tothe job. The m at ordinarily was laidlengthwise, across the runway. Lay-ing started from the middle andworked towa rd the sides and bothends. By 194 3, a technique had beendeveloped for laying m at from bothends and from the middle simulta-neously and everything usuallycame out right. A misalignment wascorrected by having bulldozers dragthe runway section into place. Anyhundred yards of locked M arstonm at always had som e stretch in it.

jected forward with speed. TheGerm ans and Japanese had nothingrem otely sim ilar to it. Neither didthe Russians until they receivedMarston m at via Am erican Lend-Lease.B y the end of the war, Marstonm at was being manu factured in analuminum alloy. Otherwise identicalto steel mat, its unit weight was 3 2.5poun ds. It was intended for spe cialairborne operations but the warended before it saw com bat.Inevitably, Marston mat becam edamaged by use, but it was not dis-carded. Field engineers developedmachinery for its rehabilitation.The d iesel-powered unit weighedfourteen tons and reprocessed 25 0mats per hour. The mats werestraightened cleaned given achemical bath, repainted, and m adegood as new.This s m all industrial plant couldbe b roken down for air transportam ong units in the field. Six C-47swere needed to m ove it. This airliftm ay seem excessive, but a C-47'scargo space was only 22.5 feet longwithin a tube ninety-two incheswide enclosing a usable 1,200 cubicfeet . A C-47's maxim um p ayload

was 4 ,900 pounds. In 1944 , a unitope rating out of Australia airliftedits remanufacturing plant through-out the S outh P acific, rehabilitatingsome fifty million square feet of run-way m at.W hen the 150-foot-by-3,000-footpioneer strip was laid at Marston inNovember 1941 it took elevendays, including the tim e to clear andgrade an area 350 feet by 3,8 00 feetand move some 50,000 cubic yardsof earth. This was regarded asbreathtaking speed, b ut during thewar years , it was exceeded m anytimes and in circumstances beyondany imagination in 1941.Almost a half century after W orldW ar II, a tourist wandering the backroads of rural Algeria, Italy, Sicily,southern France, the Philippines, ora host of South Pacific islands maystill find evidence of Marston mat. Itis not laid flat, but sometimes standsvertically with one end b uried a fewfeet in the earth, the other pointingskywardcoincidental m onumentssym bolizing an original function.After 1945 , thousands of farm ersor rural householders co llected theabandoned runway m at, pressing itshooks and slots together to createfences and walls that are still stand-ing today. They are the hilt of a terri-ble sword that has been transform edinto the proverb ial plows hare: si-lent mem orials to an air war of longago.Perversely one place where asamp le of Marston mat will not befound is am ong the W orld W ar IIexhibits of any aviation m useum .Here will be found the stuff ofaces and airplanes and alm ost noend of sentimental ephem era. B utthere is nary a word about, m uchless a sam ple of, this dramaticallysimple invention that with minimumeffort and m aximum speed carriedAm erican com bat aviation to theends of the earth.During 1941-45 Marston matcreated the footprint of glob al air-pow er. Although not possessed ofglam or or the m ystique of break-throughs, Marston m at neverthe-less ranks as one of the m ost subtle,versatile, and ultimately devastatingsecret weapons of W orld W ar II.

Universal ootprintMarston m at created a un iversalfootprint of Allied airpower inW orld W ar II. Everywhere the matwas laid, Allied airpow er was pro-Richard K Smith is the author of The irships Akron and Macon Flying AircraftCarriers of the US Navy and the prizewinning First Across The US Navy'sTransatlantic Flight of 1919, both published by the US Naval Institute This is hisfirst article for AIR FORCE Magazine

IR FORCE Magazine April 1989