Extensrvc sulveys wcle inadc of all possrble sites along the south-east coast sald Mi Colquhoun, but 11 soon became appalent that Pcgwell Bay, adjacent to Ramsgate Flarboul, clearly offered the best and most applopilate condit~onsfoi a hove~polt Moreovcl, ~t allowed space fol late1 expansion as well as meetrng the wlsh of Hovellloyd to lemaln wrthin the Boi ough of Ramsgate D V Buck and Paitners have had conslderablc expcl rence in the plannrng, desrgn and const~uct~onof polls, harbour facrllties and mailne tclm~nalsrn many parts of the wolld Theu first ~ntc~estIn hoveiciaft was 111 1962 when the first-ever passenger-carrying service was staited between Wallasey and Rhyl Commander L D Piice, RNR, who was much con- caned wrth that seivlce whrle genelal manager of the Mc~sey Felries, 1s now mallne consultant to D V Buck and Partne~s "HIS considelable experrence In handlrng large numbels of people wlll plove ~nvaluable to the Hoverlloyd opelatlon," sard MI Colquhoun

MI Edward Heath, Le~lder of he Oplioritior~,made rr short Eng~necrs of the Orgtekhsiroi bulldrng adminrst~atron in ~veek-end hovercrcift trip to France mcer~tly. He is seeit Byelolussra have developed an all-cushlon vrbroplatform whrch boa~,dingNoverlloyd's "Sur~"a/ Rnmsgate reduces the haimful effects of thc vrbration produced by such luge machrnes They have leplaced the convcntlonal mechanical suppoit by an arr cushron The new machrne costs half as much to bu~ld as the old-type platlolm and IS much mole eficliclent The new ~nstallatlonhas an all-metal vrbloplatform connected wrth the foundairon by means of an elastlc hood Thls ploduces an ail- proof chamber, Into whrch compressed air 1s pumped flom Iloverllioyd Ltd, whose 36-scatel hovelcraft has been maklng the factoiy all marn It larses the vrbromould off the supports legulai cr oss-Channel I uns between Ramsgatc Hal bour and wh~chthe concrete mass 1s compacted In Calars since May 1966. are proposrng to operate from neal by Remote-contl olled wrth the ald of a small panel, the rnstalla- Pegwell Bay when they introduce the11 SRN4 craft rn 1968 tion docs not requlie a bulky foundat~on It takes almost 2i The Ramsgate Councrl have dgieed to the burldrng of a new tons less metal to make and consumes half as much electrrc hoveiport below the cllffs and plann~ngapproval IS now berng powcl as the convcnt~onaltype sought from Kent County Cou~lcrl The vibroplatfoim of former deslgn dcsttoyed stiong steel Plelrrnrnary plans have been dlawn up foi the lamp suppolts and even Lhe foundations within thiee months of appioaches and standlng apron for the hovelciaft, a tcrminal opcratlon The arr-cush~oned vclslon, installed at Lhe Mrnsk bulldrng to house the passengel receptron hall and restaurant, plecast leinlorced conclete plant, has been operating wlthout admrnrstiatron offices, customs, emrglat~onarid health contiols, leparis foi almost twenty months and all the usual port facllltles needed to handle the half- hour ly arirval and departure ol hoverc~attthl oughout the day MI Leslle Colquhoun, clilef of operatrons fo~Hoverlloyd, stated that soon aftel the SR N6 opelairons had bcgun ~t was realised that the pi oblems of ope1 atrng an SR N4 withln the PGH-2, the hyd~ofo~lgunboat berng burlt by the Roei~~g iestiicted confines of Ramsgale Ha~bourwlthout rlsk of colll- Company 111 Seattle fox the Unrted States Navy, wrll have a slon ol serrous ~ntelferencewrth other harboui tlaflic, weie Blistol Siddeley 4,250hp Marrne Ploteus englne dliving a ccn- almost insoluble In fact, when the ha~bouiwas first seen ~n trrfugal pump to piovlde waterjet piopuls~on Water IS drawn Jdnuaiy of this yea1 doubts weie expressed as to the decisions rnto the leal stiuts of the hydroforl by the pump and dls- that had been taken, but rt was nccessaiy to cont~nuew~th the chalged thlough stem nozzles whrch ale above watei-line planned SR N6 servlce In order to plove that the difhcultres when the vessel 1s at hrgh speed Thrs system is simrlar to one that has completed mole than four years of successful opera- predicted were leal There IS now no doubt tbat the plevarlmg south-west wlnds would cause consrderable drflicultrcs for the tlon aboa~dthe "Lrttlc Squ~it"- a Boeing rcscaich hydroforl la1 ge hover ciaft as they enteled Ilaiboui A water jet has no need fo~the complicated power t~ans- In June, the Westmlnster film of D V Buck and Pdrtners mlasion system lequlled by plopellei ciaft, nerthei are theie weie appointed to advlse Hoverlloyd on the desrgn and con- any lubrrcation problems assocrated wrth keeprng hundreds of stluctron of the pioposed rnteinatlonal hoveipoit Piroi to that movrng transmrssron paits iunnrng smoothly date, the firm had been wolkrng In co-opcrat~on wrth MI The craft will be 71 ft long, and havc a 25 ft beam It wrll Colquhoun on mattcrs concernrng the approprrate s~tecondi- have a speed ovel 40 knots, and wlll dlsplace applox~mately tlons necessaiy to opeiate the SR N4 60 tons It wrll be almed wlth a 40mm gun mounted folwald These Included sea appioaches offei~ngopen watei and slack and an 81 mm mortar aft Twln 50 calible mach~neguns will bcach contours, easy access to load and iarl facrlrties and the be mounted on each slde of the brrdge space 1 equlrements needed to handle passengel and mot01-car The claft wlll use watci jet for both hullborne and lorlborne traffic through the telm~nal opeiatrons Hullbor ue, the PGK urll be poweled by a 150 hp Othcr ~equrremcntswhich have to be met lncludc cal parks, dresel engrne dirvlng a Ruehlel cent~rfugalpump stands foi publrc servlcc vehrcles and taxis and fuelllng and PGH wlll fly on th~eefully submeiged retlactable forls selvlcrng facrhties fol the boveicraft P~ovis~ours also to be whose stablhty wlll be controlled by an automatic electronrc made to incolporate a publrc vlewrng gallery on the roof of system slmrlal to the foil system used rn the patio1 c~aft"High the tcl nllrlal burld~ng A par t~cula~problem assocrated wrth Pornt", a 110-ton hyd~ofollburlt by Boelng (also powered by a the planning IS the nced to piovrde for expansroil as hovclclaft Bi ~stolSrddeley Mar ine PI oteus) whrch entel ed Navy sel vlce tlaffic rncleascs in volume Such expansion would havc to bc In 1963, and "Llttle Squi~t" callled out wrthout inte~ruptionto thc then exlsting operatrons of the hover port The followmg IS an ext~dctf~om the 29th Annual Repolt of The Denny Hovercraft, D2, wh~chhas undergone cons~del- the Air Registration Board, able modlficatlons slncc 1963 (when it suffered a setback on "Thc Boaid contlnucs to partlclpate In the provlslonal the Thamcs due to driftwood foullng and damaging the aliangements whe~ebyall cush~onvehlcles have, slnce 1960, screws) has now carl~cdout successful ts~alsin 11s modified been regulated under the plovlsions of the A11 Navigation form, and 1s expected to leave Southampton towalds the end Oider Authorrty to opeiate IS gsanted by the Mlnist~y of of Septembe~to entel selvlce abload Avlatlon In the forin of a Permit to Fly whlch exempts the Modification has Included deepening of the s~dewalls,fittlng operator from lalge pa~tsof the Ordel and replaces them with of flex~blerubber skirts fole and aft, and the re-alrangement of whatevei condrti ons a1 e cons~dered necessdi y In the partlcula~ the propelling machlne~yso that the shaftlng and propelleis case Whlle these a~langementshave bcen made to work suc- now o~eratedown through the s~dewalls cessfully, their tempo~a~ynatu~e has become an lncleaslng Commandel A F Gllllngham, who has been appointed drficulty to those concelned wlth creating and lmplementlng general managel (planning and plojects) of Denny Hoverciaft, the detall leg~~latlons sard that the pclfolmance now indicated that 11 would be able to reach 28 to 30 knots, an lmplovement of about 5 knots Plogress In the all cushion vehlcle rndustiy IS such that the Boa~dhas inveshgated fifty-nine alr cushio~lvehlcles, fifty- over the unmodihed state No detalls of the new selvlce have been glvcn but ~t is seven of whrch have been rssued with a Permlt to Fly The understood that a new company has been fosmed to opelate majorlty of these craft wele constructed by Westland Alrcraft three Denny craft In the B~ltlshWest Indlcs area, and that Ltd, Saunders Roe Division, who ale now bulldlng the SRN5 and thc SR N6 on a pt oduction 11ne basls Types st111 under contracts have been signed Frnal trlals of the craft w~llbe held at Southampton belo~e construction, and under ~nvest~gationby the Board, ~nclude ~t goes abroad, and it is also Intended to mod~fythe othel two thc SRN4 (wh~chwill welgh 160 tons and calry thirty-foul Denny hovelc~aft(one completed, the other pa~tlallybuilt) cais and 262 passengers), the Hovelmai~neHMI and Hovei- craft Development L~mlted's second cxpelrmental craft, the HI32 A numbei of SRN6 veh~cles ale being commcrclally opelated In the Un~tedKlilgdom by Hoveltravel Llm~ted,by Clyde Hover Felr~esLlm~tcd, by Brit~shRail actoss lhe Solent Mr Gerald Hodgson, product~onmanager and a direct01 of and by Hovel lloyd and Townsend Feir~esflom Dove~/Rams- Hovermarine (who is proposing to bulld th~lty-,slxty- and gate to Calais It IS planned to put the lalge SR N4 vehlcle hundred-seat 11g1d srde-wall type hovercraft) had stated that into opesat~onon Cross-Channel and Solent ioutes, p~obably oiders for two craft of theii series, worth about £120,000, ale in 1968 about to be conhlmcd Both older? are £01 slxtp-seatel ciaft. and the company is now looking fo~thc cap~tal11 needs to stall Considerable intere'st is being shown throughout the world pi oduct~on in the use of ACVs for civil, industrial and military applica- The craft wlll be made undei sub-contsact arrangements, so tions. Shell Oil Company successfully operates an N6 to supply Hovermarme has been able to keep the inltial cap~talneeded oil drilling rigs in Borneo. Following successful operations by down to £100,000 The Ion~anBank and Hill, Samuel are belng the British Forces in South East Asia, thc United States Forces app~oachedin an eBo~t to ralse money arc using N5 vehicles in Vietnam. During the past year the Board introduced the issue of 'Certificatcs of Construction and Performance' for vehicles which have been examined by the Board on the basis of the British Civil Air Cushion Vehicle Requirements. To date the Board has issued seventeen of these certificates. The British Hovercraft Co~poiat~onhas delrvered a second Because of the increased hovercrafl activity in Scandinavia, thlrty-elght-passengel SR N6 Lo British Rail Hovercraft Ltd the Board is in close touch with the Authorities in Denmark, who have been iunning a scheduled passenger seivlcc between Norway and Sweden. The Norwegian and Danish Authorities Southampton and Cowes, lsle of Wlght, since eally July with have required Air liegistration Board supervision of the intrin- thcl~first SR N6 sic safety of the SR.N6 vehicles in the hands of local operators. The second machine IS belng used in~t~allyfo~ training but As a consequence of the continuing export of ACVs, the may later be operated between Cowes and Portsmouth It w~ll Board is giving advice on air cushion vehicle safety to a also be used as a rellcf craft on the Southampton-Cowcs number of overseas Authorities. seivlce whlle add~tional equ~pmcntfos n~ghtoperations 17 The Board has selected one of its staff test pilots to specialise belng fitted In the fi~stSR N6 in the operational testing of ACVs. In June the Air Cushion Vehicle Co-ordinating Committee issued its study "The Safety Regulation of Air Cushion Vehicles"; this study is an interim report wl~ichdiscusses the principles which should be applied and emphasises the urgency The Soviet hydrofoil Borneta arrived in Piraeus, Greece, of passing at least the minimum "enabling" legislation to facili- recently and remained lherc for a few days. It was visited tate domestic arrangements and to enable international dis- by various shipowners who may eventually place orders for cussions to proceed in the most satisfactory manner. Nearly similar ships. 170 copies of the study have so far been distributed, some of the recipients being the appropriate Authorities of Australia, Canada, Denmark, France, Germany, Italy, Japan, Nether- lands, Norway, Sweden and the United States. The work in which the Hoard is now involved confirms only Japan, one of two countries in which Britain has granted too well the validity of the view of the Air Cushion Vehicle licences for the construction of hovercraft, has won her first Co-ordinating Committee, that lack of allocation of permanent export contract for an air-cushion vehicle from her shipyards. responsibilities is a growing hinderance to the economical Mitsui Shipbuilding will make a 10-seater craft for Thailand administration of the safcty requirements for Air Cushion Custon~s. It is to be delivered next July and will probably Vehicles." cost f 65,000. Ambassador Herzry Caboc Lodge and Rear Admiral N. C'. Ward, Head of the Naval Advisory Group in Viet Nam li;\ten intently as Z,t Kenneth Luerlser, Commander of Patrol Air Cushion Vehicle (PACV) Lliviuon 107, purt of Boat ,Sguadroiz I, Military Assist- ance Command (Viet Narn), explairzs how an ACV worlcs

Three air cushion vehicles were delivered to the United States Navy under a 2.6 million dollar contract awarded to Textron's Bell Aerosystems Company and have been oper- ating in South Viet Nam since May, 1966. They have several advantages over other patrol craft : (1 ) greater speed; (2) long endurance; (3) zero draft; and (4) high resolution radar, and have operated in seas up to 7 ft and winds up to'35 knots

A ,scrnzl~arz is searched for possible co~ztrabarld offer being intercepted by cln air c1rsl7ion vehicle. The ACVs can chase suspected Viet Cong vessels at speeds up to 70 mplz across shollo~cl ~vatc~.sand 1111 01% to the bec~clzi/ ~lecesscrry An amphibious air cushion vehicle transitions from water to land as it rcturru to its Cut Lo base near Vung Tau in the Meltong Delta region of ,South Viet Narn. In the background are conventional patrol craft operating out of the base

Called "Charlie Victors" by their crews (which consist of an operator, radarmanlnavigator, gunner and maintenance chief), the SK-5ACVs are being evaluated by the Navy for coastal surveillance, intercept and investigation to help prevent seaborne infiltration and supply of Viet Cong units in South Viet Nam. The craft are also being evaluated for air-sea rescue, medical evacuation, logistics and emergency resupply. Armament includes 50 caliber machine guns to assist the crew in performing their missions

A sampun i~ boarded to be seurchrd for ~ossible contra- barzd after bcing intercepted by an air cu~hion vehicle. The ACli is 3Y jt long, has a beam of 22.9 ft and is 16 ft high. A Gcnerul Electric LMlOO marine gas turbine engine with 1,000 slzp drives both [he 7 ft fan and tlze aft-mounted 9 ft propeller SPAC AN COMM

Ronald Cole

the suiface effcct ship (SES) concept However, the systems ME tho~o~ighncssand completeness in all areas ol Amellcan apploach w~llbe used, and manning and management will be T technology sets examples which the lest of the woild studied to the extent that they are essential lngledicnts of elthe1 follow oi t~yto emulate Now and agaln a few cases englneellng an ope~ablesy5tem Srmildrly economics will be arise whcie a new ~deahas been developed to an advanced consrde~edin tellns of cngineeilng, construction and operatrng state betole the Americans have become awaie of its poten- costs, wheieas mattels of revenue such as alternate speclfic tlahties Thrs happened In the case of the turbojet englne and routes, caigo availablllty and profitab~lltyw~ll not be part ol In mole recent trmes in the case of su~faceeflect vehicles the study The study emphasises commeicral transoceanic appllcat~ons In vlew of the lead in hove~c~aftdevelopment held by of the surface effect concept Military application and feedel H~~taln,any publ~shed paper or study on the subject coming seivlces by SbS will not be studled The study w~llconcentrate fiom America must be calefully studled by expeits On the one on the captuied all bubble (CAB) and channel flow concepts, hand it 1s potentially the hatblnger of a challenge On the but othei concepts wrll be sc~eenedfo~ the sake of complete- othc~it is also almost sure to contarn some obseivation oi ness iemaik that could be usefully heeded ol that may point to impending l~nesof ~esea~chand development Comment Overall one can be sure that II the Ameiicans ente~the field Later on, the CAR vehicle is defined as one using a cushion at all they wrll do so with the inlentloll of bang able to pul of all and IS defined as a Category I vehicle Those employrng the11 loot rn the door techn~callyahead of anyone else It 1s llft duo to trans~tspeed ale tc~mcdCatcgoiy 11 vehicles commonsense to assume that they w~llnot try to sell someth~ng Two ~nteiestlngand rmportant polnts emelge from the over- that is a11 eady avarlable all br~ef Conceinlng concentrat~onon the CAB and channel Over the past yeals several studies of susface effect vehicles flow concepts, ~t 1s worth noting that these have not so la1 have been made in the USA both fo~the govcinment and been seen outside Ameilca The CAR may best be described tnterested ente~pilses One of the latest to have been publrshed as a sldewall hovesciaft having strfl end walls that flex as they is entltled "Su~face Eflect Sh~ps lo1 Ocean Commeice" ineet waves Lt is even mole interesting lo muse on why the (SESOC) lt is Lhe final report on a study of the technolog~cal brief should reyulle concentrat~on on these two concepts In pioblems by the SESOC Advisory Colnmittee whlch was con- the first place such an lnst~uctronmay Imply plior knowledge vened by the Commerce Technical Advisory Boa~dTt was pub- of the11 supe~~oi~ty~elatlve to othcr types Secondly, 11 could l~shedby the US Depa~tmentof Commerce In Februaiy 1966 be to avord involvement ~n othei people's Ideas and patent We are mdebted to the US Depa~tmentof Commerce lor lights Notlce also that by rmplrcation, ex~stlnghovetciaft tech- permisslon to leview the iepolt and pirnt some extiacts from nlques are coveled by the last few words, "other concepts w~ll 11 We also recognise that 11s contents do not necessatrly be sc~cenedfo~ the sake of completeness" represent the policy 01 plans of the Depaltment of Commerce or ol any othcr Federal Government agency The possibilrty of usrng suiface effcct ships (SES) to rinplove the transpoltatron spectrum by el1ectlvely fillrng the gap F~vespecific goals wele set for the con~mitteeas follows between exrstlng an and shrp selvlces brrngs in ~tstram the 1 To ldenllty those technolog~calproblems whrch ale impol- need fo~considerable technologrcal development This appeals tant to SES development to be so great that the US Department of Commerce was 2 To ~dent~fyand define those technological p~oblemswhlch plompted to conduct a Ilgorous revlew ol the technolog~cal ale cruc~alto SES development problems lnvolved 3 To rank the cruc~alprobleins in order of ~nipoitanceLo the The Surface Effect Shrps lo1 Ocean Commelce (SESOC) success of the SES proglammc Comn~itteowas foimed and this had five suppoitlng panels - 4 To tank the clucial ploblems In oldel of dificulty to each belng charged with one 01 more technrcal areas Oveiall solution membciship rncluded no less than foity voluntee~ screntrsts 5 To recommend the magnitude, t~mephasing and scope of and engrneeis of nat~onalstatus d~awnfrom ~ndust~y,educa- effect~veR & D programmes to resolve the problems t~onand Goveinment offices As a final task a th~ce-part deslgn study was to be M~sslonof the study was delibei ated upon To determine the iesea~chand englneerlng problems asso- 1 Cons~deiat~onwould be restiicted to caigo line1 systems clated with employing the suilace eflect ship concept in coni- handling a typical spec11urn of high value conta~ncrrsed mercial ocean t~ansportation system cas go To ~ecommend a ~eseaich and development plogramme 2 The study will Include all concepts of SES competent to ~esolvesuch technolog~calp~oblems 3 The hypothetical SES would have a gloss welght or about A fulther series of notes delineated its scope st111 fuithci 5,000 long tons and would ciu~scat a speed of about 100 The study emphaslses the iesearch and engrneerlng aspects of knots Comment The channel-Row data was supplled by Vehlcle Research Relatlve to the th~rd and last task, Biitlsh Hovercraft Corp, and Douglas A~rciaftCo These claft wele des~gnedto Coiporat~on'sHovelfleighter levcaled at the B~owndownShow glve 4 ft (1 2 m) ail-wall clearance beneath the s~defloat and takes on a very Impo~tantaspect although there ale d~fferences thrs would enable it to negotiate 8 Tt (24 ln) waves On this des~gn flaps conta~n~ngnozzles ale lowered dt the flont and In specificat~on The Blitlsh design IS quoted at 4,000 ton (4,064 tonnes) and of thls 2,600 ton (2,641 tonnes) would be lcar end of the chanilel so that fo~stationdly hoveling the payload A cluislng speed of 50 knots (92 6 km/hl) would be claft becomes an annular jet type Dunng acceleration the Raps typical Length being of the older of 480 ft (146 m). would be prog~ess~velyclosed and aelodynamic 111t would take over At the tlme the repo~twas wl~ttenthe type had only Whlle numerous exlsting repo~tswere made available to the hovered main committee and the five technical panels, othels weie pre- Douglas Alrcraft Co suppl~eddata on the Wieland WIG paled spec~ficallylo1 their study In th~srespect, Booz, Allen craft and they have in fact ploduced a manned model for test Appl~edResearch Inc, piov~dedlu~thel back-up data for their pulposes This is powered by two l~ghtalicralt englnes each five ex~stlngreports as well as a plcv~ouslyunpublished one driving three-blade tract01 anscrews This type cannot hovel Anlongst other papers and commun~cat~onsseveial firms not and operates like a flyrng boat iestr~ctedto an altitude of only yet wldely associated with such veh~clesadded the11 weight Of a few feet above thc sulface It employs a tandem wlng these North American Av~ation Inc, Douglas A~ic~aftCo, arlangement wh~chIS ~ntendedto make 11 inherently stable in Lockheed A~ictaft Co~p,No~thiop Corp, Boe~ng Co, and altitude and p~tch Aciojet-General Corp, should be ment~oned 111 fact a very The five panels we~eeach allocated a technolog~calploblem la1 ge plop01 tion of the American Ael ospace ~ndustry,when area and wele ~dcnt~fiedby a number and the11 title Thus you add Bell and Republ~cwho wele well ~ep~esel~ted Panel 1 consldc~ed Aer o-Hydro Dynam~csand Control, Panel It is also of inteiest to note hele that although data on 2 conside~ed Speed, Resistance and Seakecplng The othels B~it~shhovercraft such as the Vickers VA-3 and SIIN5 was covered Propulvon, Hull and Operat~ons At the fi~stpanel avallablc via Republic and Bell, ~t featuied but very l~ttleIn meet~ngrt was agieed that the or~ginaltask was too b~oadto tho lcad~ngand dcllberatlon of the panels Yet leports based tackle In the time available Thus they suggested that thc most on ear he^ project studles unde~takenby non-manul'actuling piofitable approach would be to sta~tby cons~dellngthe Booz, coilceln (Booz, Allen Appl~edResearch Inc) and otheis hav~ng Allen leports prepaied for the Mallnc Association only d fractron ol the Br~trsh experience were piom~neiltly As a result the following set of panel Vasks was applovcd by featured Thls may underline an appalent object~veof takrng the main committee a completely fresh approach to the subject I To evaluate the technical assumptions made by Booz, Allen In determining the functional and economic capab~lities of the five SES concepts. 2 ldent~fythe iesearch and engineering p~oblemswh~ch 5hould Study of Types be solved In accomplrshing development of the vaiious SES All the well known, as well as the not so well known types concepts Dec~dewhich piohlems could bar successful devel- of SES were consideied In outllne deta~land ~t is woith run- opment and which relate to achreving supeiiol perColinance nlng through them All weie reduced to the Categoly 1 cush~on of the p~ospect~vevehlcle To the extent that tlme pelmits, lift, or Categoiy IT aeiodynamic lifl types consrder the time requlrcd for the~rsolut~on and suggesl approaches to the solut~onwhere possrhle The captuied alr buble (CAB) 1s one w~thside walls and a curtarn of skis which lightly brush the water surface at eithel 3 Consldel each concepl in terms of the crucial problems and end and so form a seal Son~eea~ly ~nstability problems weie the prospects for their solution, deteim~ne, if poss~blc, encountered wlth this type and a solution was found ln arop- whcther the concept is eliglble for early development or ping tho stern end so that it would just rrde in the watel and so bailed liom eaily development 01 whcther the ev~denceis torrn the aft seal In this form the CAB veh~cle1s known as inadequate to make a decislon at th~stime the Hydlokeel The malo; pa~tof the Booz, Allen lepoits and staff weie available to the panel5 wh~leothei techn~callepolts and Inputs By replac~ngthe canted platfolm of the Hydiokeel type with fiom ~ndustrywe] e also dlstr lbuted a thrn aeiofoil sectlon and arranging fol sldewalls to not quite touch the water one gets a ram-wlng design Reduc~ng the angle of attack of the aerofoll and retaining the sldewalls gives the channel-flow wing A wing fly~ngjust a few feet above the At this polnt w~ththe techn~calpanels gettlng down to wolk surface IS of cou~sein giound effect and the sole des~gnin on ieports that had been complled by a data and statistics this category 1s the Welland craft known as a WlC? (w~ng-in- collecting concern, there was a d~stinctchance that the object gr ound-effect) deslgn of the whole exeicise would be lost In fact the whole com- mittee could have become a vict~m of closed-loop thinking All the major types weie commented upon although En most based on inputs of doubtful value cases there was very llttle that could be sa~dFoi ~nstance, It 1s to the cledit or the panels thal this did not happen In expeliments have been caiired out with a small manned CAB fact the11 fi~sttasks resulted in comment and clit~c~smol the type dnd nume1ou5 models have been tested Most of the data conta~nedin the Booz, Allen ieports. des~gnwork appeals to have emanated f~omMr Allen Ford of the Dav~dTaylor Model Bas~nand deslgns fiom 100 to 10,000 ton5 have been studied Perfoiinance culves we~epiovided fol all these and 11 was assumed In all cases that cledlance was Slnce a lot of t~meand effolt was spent in consrder~ngthe suficient to plevent base contact w~th8 ft (2 4 m) waves Booz, Allen repoils 11 IS necessai y briefly to outl~netbeii con- Data lo1 the Hydlokecl was piovlded by Bell Aciosystems, tent Some ground lules we~emade and applled generally to and coveied craft oJ 100, 500 and 1,000 long tons L~kethe all the repolts These were to the effect that engineering 'data other CAB types they employed a sprlng loaded flap but at the foi the paltrculal type of SES would be gene~atedfor them by front end only The s~dcwallsglve an appiecinble buoyancy to the designer5 or the claft If in need of mod~ficat~onthen this give stabil~tyin loll The undersulface of the hull 1s qubslan- could be done by Booz, Allen w~tbctdvlce 11om the appropr~ate trally flat and the aftel end planes on the sultace to glve some des~gnel Secondly, sufic~ent11ft powel would be ~nstalledto lrfl It was noted that thls type suliers a consrderable rcductlon glve an all-wall cleaiance of 4 ft Acco~d~ngto lnfolmatron of speed with incieaslng wave helght slnce a greatel propoition ava~lablcIn 1962 thrs should allow operation in 8 ft waves oJ the hull becomes affected Also the stern tends to follow wrthout loss ol speed Thi~dly,~f the wave he~ghtwele less the wave contour veiy closely and as a ~esultg~ves irse to than 8 €1 the l~itpower used would be educed to grve an ail- p~tchlngaccelerations gleatel than those expeiienced w~ththe wall clearance. of 50 pel cent of the wave he~ghtdown to a plain CAB type mlnlmum of 2 €1 The Booz, Allen Reports 1. Stability and control criteria. The first, ent~tled"An Econom~cFeas~brl~ty Study of the 2. Stability modes: 100-ton Mart~mcAdmlnrst~ation Surface Eflect Ship" was a. Pitch-Heave stability. begun In February 1963 and rssued In November of the same b. Yaw-Roll stability. yea1 It was based on englneellng data supplred by Vehrclc 3. Control systems, concepts, reliability and life. Resea~chCo~p (VRC) The repoit lnvestrgated rn deta~lreglons 4, Dynamic loads implications of stabilrty solut~ons. of the world whele such a vessel may be used and the most In evaluatrng the concepts p~escntedto 11 the panel ejected promlslng types of caigo rt could carly They cons~dereda sea the WIG and channel-flow p~ojects The WIG because lt 1s state In whlch a wave herght of 5 ft 01 more occuired 10 per analogous to an ancraft whlch demonst~ateshigher eficiency cent of the trme If the wave helght exceeded 8 ft the servrce when Ryrng h~ghand fast Also there was the problem of was'suspended or the c~aftwas perm~ttedto detou~the alea, hdndllng such an eno~mousvchlcle at the te~mlnalareas The thls amounting to a 50 pel cent Increase in routrne distance channel-flow 1s at too eaily a stage of development to perm~t Based on ext~emely forward thlnking the second repo't, deta~ledevaluation "The Technical and Econom~cFeas~bllrty Study of a Nuclea~ In add~t~onthe panel wele unanimous in the oprnlon that Powered Surface Effect Sh~p"was started In August 1963 and all the concepts have aeio-hydro dynam~cstabllity, cont~ol rssued In Janua~y OF the following year It concelned an and response problems, se~rousenough to preclude develop- annular jet type SES and ~t IS to be noted that Booz, Allen ment of a la~geSES at th~st~me They go on to ~ecommend themselves genelaled a gleat deal of the technrcal data for an explo~atolyappioach including the construct~onof manned lalge SES's partrcula~ly that pertaming to stlucture werght craft In the lange l~omfive to twenty-five tons Therr trme Power ~equliementswere based upon Bell Ae~osystem'sfind- cost estrmate 1s elastic, varyrng from five years and fifteen rngs In thrs class of vessel the a~r-wallcledrance was raised to mrllion dolla~sto ten years and fifty m~llron dollars fol the 8 ft thus peimitting waves of 16ft to be negotiated w~thout reallsation of a large craft loss of speed It 1s stated that srnce Repolt No 2 concerned a passengel- Panel 2 Report carrylng desrgn, it was not necessary to d~scussor cons~der~t Agdln the panel was crltrcal of the Booz, Allen figures, But Report No 3 compares foul examples of SES types, rnclud- addlng that they weie In ag~eementwith the smooth water rng a nuclear poweled an nu la^ jet type, almost certainly that d~agfiguies if no considerat~on was given to achrevrng cons~dercd~n Repo~tNo 2 Other types cons~deredin the thud stabihty Lrttle 01 no data was ava~lablcto them on the drag paper include the channel-flow, the convent~onal-powered cost of achrevmg stability Solutron of the stab~lltyproblems annular jet and the W~elandWIG design Data was obtarned should alm at minimlslng ~es~stance~n the attainment of for all des~gnsup to 1,030 long tons stabllity It 1s most lrkely that early des~gnswould have lrft- The same bas~cpattern of assumptrons as made In Report drag rat~oslnferrol to those assumed No I were applied but addrtional data fo~the annular jet In the course of detalllng theii thoughts on stabllrty diag systems was supplred by Bell Aerosystenis Srnce these applied they mentioned that end seal flap d~agfor the CAB vehicle to an arr-wall clearance of 2 ft Booz, Allen mod~fiedthe data had been taken as 50% of the cor~esponding annular skiit to apply to a 4 ft ail-wall and ve~~fiedtherr est~matesby lefel- dlag at zelo daylrght clea~ance The figu~es havlng been cnce to Bell obtained by Republrc on tests wrth the V~ckers VA-3 It Thrs ~epoltconcluded that the cost in dollars per ton-m~le was thought that thls was the best avarlable ~nformatronupon varled w~ththe gross werght and the range In much the same wh~chto base estimates Tarl fin? and control elements for way for each des~gnFOI any gross wcrght there was an opti- yaw would add drag, as would the effect of p~tch~ngmotrons islum range of about one filth oi the ult~mateand thls gave by incleaslng the wetted areas. Srmllally, contounng the waves minlmum cost Also ~t was found that the larger the sh~pthe In heave would glve drag ~eductlonsthrough decieased wetted lower the opeiatrng cost But In all cases the cost of the aiea annular jet wele much greatel at optimum lange than fo~the They also noted that sea-keep~ngproblems for the CAB other desrgns It also appears that optimum langes were them- were not tackled The desrgn of such ci-aft could be greatly selves much less and of about 200nm at 1,000 long tons gross influenced by the plovrslon of adequate seawo~thlncss and Q we~ght the desrie to ach~eveacceptable motions lor clew comfo~t The study of Repo~tNo 3 was extended to cover two addr- All lhrs was very important when operating In seaways and t~onaltypes, namely the Hydrokeel and the CAB Fol the pi actlcally no hard data exlsted on the subject Only pre- later, des~gndata was supplred by Mr Ford but no commercral Ilmlnary study of a buoyancy stabrlrsed 3,000 long ton CAB data was avallable Oveiall, Repo~tNo 4 showed that the veh~cle in d seaway had been carr~edoul Th~sstates that 7p. Hydrokeel Involved even hlgher costs than the Hyd~osklmme~ response 01 the vehrclc at varrous speeds and In rea states but the cha~acterlsticsof the CAB appealed to be much bettel 1s h~ghly dependent on the sidewall buoyancy and bubble and wele compaiable w~ththose of the VRC and WIG dynam~cs Very high leakage rates can be ant~crpatedat speeds designs It was thought that the CAB gave rlse to fewer devel- of 100 knots in seas gieater than state 3 IS heave accelerations opment p~oblcmsthdn the chdnnel-flow and so deslgns wele ale to be kept wlth~nhuman tolerance levels extrapolated to consrder realist~c wave condillons on trans- Much of this prnpoints the development of adequate flap atldnt~c~outes The ~esultsshowed that furthe1 invest~gation seals and sufficlcnt stlnness fo~stabrhty dnd able to ass~st would be just~fied the ~egulatronof the alr bubble Passrve seals would have to Because of the absence of any commetc~aldes~gne~s of such have a low stlrness rn older to achreve high frequency c~aftBooz, Allen with assistance flom MI Ford inve5trgated iesponse rates Thrs would p~obablylead to the development I the detalled chaiacteristics of a 5,000 long ton CAI3 craft Th~s of an actively controlled flap wblch may be p~efe~~edto the data was made ava~lable passive type Fulthelmote, there 1s a suggest~onthat blowe~s I arc ~equr~edthat w~lltend to allevratc the mot~on~assocrated Panel 1 Report w~thbubble compress~bihty Whlle they agreed that assumptrons had to be made In oldel The panel also thought that the Booz, Allen assumptrons on I that the Booz, Allen ~eportscould be wr~tten,they d~dnot the rncreased drag due to waves wele qulte c~udeand In some agree wrth those assumpt~ons They were stlongly ol the ways optrm~st~cThey go on to clrtlclse the valrous assump- oprnron that the technology for la~geSES's capable of 100 to tions made, but generally agree w~ththe alr drag figuics 150 knots (185 to 278 km/hi) 1s not suficlently avallable at An encouragrng porn1 noted here refers agaln to the Republic thrs polnt It would not be poss~ble to ensue adequate tests on the VA-3 I-le~eexpcrlence shows that by using the stabll~ty,control and lcsponse cha~acterist~csfo~ vehicles rntl- F~oudescalrng laws one can alrlve at a 9,400 long ton verslon mately associated with the suiface ol the sea They consrde~ of the VA-3 capable of 100 knots In a sea having an avelage that the~eale four areas In which the lack of background ex- wave he~ghtof 30 ft But it is noted that while these results perlence p~ecludes the ~mmedtatedevelopment of any large w~llhold good fo~any ACV type, 11 1s not to say that they vehlcle They ale wrll hold good fo~a CAB type They also noted that the cost pel ton mlle of CAB types Neilher the magnitude of these cflects no1 the solut~on was ext~clnelysensitive to changes In the hft-d~agratlo An of the problems has been deteimlned for lalge englnes Increase ol 25% In th~sratio would Increase the cost per ton at sea The est~matefo~ a 6% powei loss 1s consldeied mile by 130% They lurthel note that 111 vlew of the plesent conservat~ve aleas of Ignorance such a varlatlon In the performance esti- B P~essurcdrop m the Intakes foi ~nletwatel separat~on mates can be anlic~paled In thls lespect ~t was noted that and exhaust ducting inus1 be consldered opelatlon rn a seaway and Lhe corresponding Ingh ~es~stance C De-lung of the Inlet air must be p~ovided had not been consldered D The plesent status of the sulph~dat!on problem 1s such On the question of development they thought that a lot can that there IS no assui ance that tu~bineInlet temper atu~e bc ach~evedby labolato~yand manned model tests as the laws can be extended beyond 1,530" F w~thoutadded man- of scalrng and the11 applrcatlon wele qulte well undclstood tenance The extent of this cannot be detelmlned at this The conclus~onwas that lmmedrdte mlt~at~onof des~gnstudles t~meSuch a ternpelatule Irm~tat~oncan result In lalgei fol 1,000 and 5,000 long ton veh~cleswlth research only being engines, greater weight and h~gher fuel consumpt~on In a supportrng role was plemature Feaslb~l~tyof the SES with thrs lalge~engine should be considei ed Propulsion Panel Report E Booz, Allen assumed that the tu~blne holsepowe~ In Lhe maln, they ag~eedthat Lhe Booz, Allen assumpt~ons changed an average of 0 005 hp/hp/degiee F In ambient were feas~ble In the 1975 pellod, but optlm~st~ceven IT an tempelatu~c Although not stated by them, this 1s aggress~vc development programme wele followed Of most approxnnatcly tlue rf the firrng tempelature IS held concern wele the assumptions wh~chInvolved the ab~l~tyto conslant In the loute analys~san engme SFC oC 0 55 design a pract~calshlp with ieasonable l~leexpectancy and was ass~~medplus a correctron iol change In ambrcnt rel~abilitywlth~n the projected weight range In thls general temperature Fol ease of calculation, the effect of tem- d~rectionthe performance of an SES IS shown to be partrcularly peratule valiations wh~choccui on various loutes was sensltlve to plopuls~ve eficlency, rue1 performance and assumed to change SFC rathe1 than ho~sepowel by machine~ywclght It IS noted that most of the assumptions a lac101 of 20005 hp/hp/degree F from an assumed In the report? have been developed lealist~cally,but they ale mean of 60" F Furtliesmore, the SFC was ~ncleased not backed by deta~ldes~gn studles Due to the lack ol such by 0 06 to account lor salt fouling studlei, 11 13 lmpossthle to ldentlfy the necessary components What appears to have been overlooked 1s that the and their operational iequlrements or the effect oi these In- lactor of 0005 hp/hp/degrec F applies only at a con- slallatlons on lhe shlps' structure and slze cha~acterlstrcs stant fii~ngtemperatule When a fixed powel output IS Furthermore, it IS ~mplrc~tIn the Booz, Allen studles that requ~red of a fixed geometry tulbine 11 1s obtalned all or the probleins can he solved so that a hlgh pe~forlnance by varying the fi~lngtempe~atuie w~th change In am- sh~pcan be bu~lt,'such a ship be~ngfully compet~t~vewlth blent Thls effect 1s to glve an almost constant SFC other systems Yet the assumpt~onsmade with respect to pro- wlth val lat~onsIn ambient at a fixed power output pulslon are optlmlstlc in all three categor~esment~oned above The problems of transmisslor1 system development va~yIn In add~tlon ~t IS evident that insufic~cnt data IS avallable degree wsth the various propulslon systems, commenls follow to predrct accurately the powei ~cqu~iementsand speed pel- A Water screw with lncl~nedshaft The gear developmerlt formancc The ult~matedec~s~on lo pioceed with the develop- appeals to be withln the state-of-the-ail ment of a commercial ship w~llno doubt depend on whethe1 B Watel screw w~th light-angle drive and iet~actable or not the assumptions can be substant~ated nacelle Gear development iequlres consrderable de- Cornmeal velopment and may have an unacceptable llfe C Water jet system Gear~ng1s wrthrn present know how Slnce the del~berat~onsof the Piopuls~otlI'anel contained It may be poss~bleto avo~dgears and employ direct by fa1 the greatest we~ghtof tecllnlcal argument and detail, 11 dnve is being quoted at somewhat gieate~length Aspects such as D A~rsc~ewNo ~nsurmountable pl oblems, but lequrt es the sulph~datlon of englnes, g~owthof SFC due to salt de- consldciable development and may still have unaccept- position, power deglat~onand the types ol p~opulso~ale ol able l~fe Un~tpowel outputs wlll require extend~ng paiticular Interest, and the mole so when lead wrth the BHC plesent knowledge on planeta~ygear systerns HoverTreighter in m~nd A piopulslve eficlency of 67% had been assumed In the economlc analys~s Wh~lethis value may be ach~evedwlth Only the Booz, Allen assumpt~onsielat~ng lo the 5,000 long anscrews, a figure of 60% may be opt~mlst~cin the case of ton CAB des~gnwere consrdered, slnce Lhelr ea~lleisludles watel screw and water jet propulsors Thus Lhe economics d~dnot define the propulslon systems The followlng evalua- could he less attractive It IS also Lhought that propuls~on tlon 1s therefore based on the one p~oject mach~ne~y we~ghts ale underest~mated A fguie ot 2 1b pel Slrnple open cycle ariciaft gas tu~b~neslep~esent the most Installed holsepowel appears more real~strcTor each of the suitable prrme move1 avallable F~Iall types of SES No systems amount 01 practical ~mprovement111 fuel consumpllon through the use of re-genesatlve systems could offel the advantage In machinery we~ghtoflered by this type What 1s more, englnes The inodel and data puhl~shedon the BHC Hoveif~elgl~ter ex~stwh~ch provlde the approx~matethermodynamic pelform- gave no inkllng as to the type ol propulslon system to be used ance required, although they have no1 demonstrated the11 It was po~ntedout that anscrews of the order of 40 it (12 2 m) ablllty to produce the hlgh power level requlrcd In con- dlamcter would result if this type of propulslon was used In t~nuousopelatlon Anclaft fuels ale acceptable fact a plact~cal cons~deiation would be the employment of Ove~all,Lhe st~ldywas based upon the SFC and operatmy hel~coptel rotors Instead ol convent~onal allscrews My own chalacteristlcs and growth potentral of the Pratt & Whltney guess IS that res~dualth~ust fion~ the eight BS Olympus tul- FT4A-2 engrne Th~sengrne has not yet demonstiated its bines plays an lmpoltant part in the project The d~rectlyaft abll~tyto produce powel In the 30,000 hp blackct fol extended facing exhaust plpes displayed on the model give a clue to th~s per~ods It has ach~evedth~s output apploxrmately fol short per~ods and developn~entto long endurance seems feas~ble The installed englne powel and SFC assumed appeal optl- In Lhelr genela1 surrimlng the panel leaches some interest~ng mlst~c The followlng cons~deiatlonswould ~esult111 g~eatei conclus~ons To them it appears that there ale no propulslon spcclfic welght and fuel coilsumptlon problems that ba~the development of an opelable seawolthy A To avo~dexceed~ng 6% powel degladatlon 11 may be craft fol limlted use as a Lest vehlcle But systems developlnenl neccssaly to shut down each englne per~odically fo~ fo~such ciafL would not be applicable In a comincrcrally com- water washlng Thls would iequue a nxnrmum of ten pet~tlveship The powel requirements fol SES cannot be ple- mlnutes pel englne The use of ab~asrvesmay clrcum- d~ctedat th~st~rne because of the lack of expellence and data vent the need fol washrng and the inopelat~veper~od on drag charactelistics and speed pellormance The bas~c~nipoltancc of propulsive ellic~ency and SFC 3 Substantral reductions In structu~alweight appear pos- stenis f~omthe11 strong lllfluence on total fuel werght lequrre- sible through large lncleases rn bubble plessule leadlng ments In the case of the 5,000 long ton sh~pth~s rcplcsents a to a more compact sh~pI'he amount of welght savlng far g~eater Jract~onof the total we~ghtthan any other Item thtough thrs approach has not been puisued since 11 15 A percentage change In e~thetfact01 wrll tesult In a vely g~cat allrcd wrth propuls~ori~equ~rements change rn payload capaclty and a compoundrng ol thls enect 4 The use of hrghel stiength aluminium alloyr and101 on the econonxc charactc~~st~cs steel may offer a we~ghtadvantage Further study of all Although engrnes ex~stwhlch could meet the luel consump- the factors involved rs ~eyul~edbefo~e thia can be tron figules and powel output ovel long perlods, they wlll dcc~dcd need a long development pel rod The ball 1el to the] modynamrc 5 O~~ginalBooz, Allen estlmates for the stluctu~alwe~ght implovements occurs at approximately 1,530" F through sul- In the case ol the 5,000 ton CAB wele bared on a bubble phldatio~l corlosion whrch IS to be expected in a ma11ne plcssure of 280 lbi sq ft (1,367 kg/sq m) The11 estlmate atmosphere Othe~ colloslon problems ailse due to the de- was 101 3476 ol the gloss welght and then personnel ponrtlon of salt III valrous palts of the englnc, but thls rs a belleved that th~scould be educed to 25% In fact their lersel p~oblen~Engine pelfo~mance 1s also subject to dc- economrc analys~s was based upon an assumed 20°/, ter~o~at~ondue to the deposrtron of salt rn the complessor level Thus ca~efulattent~on must be glven to the removal of salt Only the CAB concept was studled by the panel watei In the intakes and the minrmisrng of both rntake and The panel unanrmously doubted the figule of 20% and exhaust p~essule losses Operating regimes wrll have to be considered it fa1 too optrmrstrc Lo be used to1 economic estabhshed that will allow watel washrng of the cngrnes durlng studles They also had doubts about the 25% level transrt Thus, ce~tarnwe~ght and space penalt~esw~ll result In the case of a SES 11 was agl eed that no structu~aldamage l~ornthese ptovlslons and they wlll rnfluence the number ol could be tolerated under all condrtrons oT "on bubble" opera- englnes I equrr ed t~on But a cl~trcal des~gn condrtlon would lelate to the A~rsclew plopuls~on offers the best shalt and long te~ni emergency circumstances when such veh~clewould havc to solutron for a h~gheffic~cncy system, partrcula~ly~f the trend w~thstand a heavy sea In the drsplacement cond~t~onIt was 1s towa~dsh~gher speeds, re, the 125 to 150 knot b~acket also agleed that rf SES dcs~gn cr~terlarequi~ed the same Watel screws and wate~ jets Impose a number of drficult structu~allntegr~ty now embodred In displacement sh~pdeslgn, mecllan~caland structu~aldesrgn p~oblemsIn addrtron to the then the lesultlng st~uctu~ewould be too heavy to perm~t task of desrgn~ng an eficrent propulso~ 7 he effic~ency oC a pract~caldesrgns Thus, although a substantla1 margrn would watel propulsion system wlll be less than the alr propuls~orl bc iequlred, 11 could not be as much as for a conventronal system at 103 knots and even less at the h~ghelspeeds rhrp They go on to comment that the p~esent resurgence of A varrety of studres would have to be made to clar~iyseveial intelest In SES coi~cepts sterns from the development and questtons Of there, that of an acceptable envelope ol speed favourable expellence w~thvarlous types of Rex~ble under- velsur sea slate and ansocrated structu~al~equrrements 17 of structures. These make 11 possible to leduce the arr gap and prlme lmpoltance Also the sever~tydamage would havc to be hence the power needed Lo sustaln the cushron The studlea related to the valrous sea condltrons, agaln what structu~al plesented to them rndrcated that the lrft powel would not ct~telrashould be imposed bearing thrs ~clat~onsh~prn mlnd exceed 10°6 of the p~opulsronpower requrlement But because Llght stiuctures subjected to dynamic loads suffer from a of the many unccrtalnl~es ~nvolved ~t is poss~ble that the seveie lat~gueproblem and a surtable spectlum of dynamrc actual rcqu~remcntmay be two or thlcc t~mesthls value It load~rigwlll have to be employed as the basls of fatrgue- is noteworthy that a lelative Inelease of lrlt In relatlorl to res~stant desrgn Frnally, a spectrum of statrc and dynam~c p~opulsrve power w~llp~oduce an eflectlve equrvalent to a loads wlll have to be evolved lor use In the CAB desrgn ~eductronIn the propuls~vcelficrcncy There 1s a conslderable amount of related experience avail- L~ttle, ~f any, useful rnfo~mat~oncan be obta~ned it om able t~omshrp and a~rclaftdes~gn practrce and some of thls model tests, evcepl pelhaps rn the case of the actual pro- may be employed But fo~large SES ;ych~cles the lack 01 pulsors Full scale development testrng will be lequr~edfor model test data precludes lntelhgent decrs~ons on such ~m- both the engrne and transm~ssronsystems Design studres are poltant mattels In addltron to model tests and studres, actual necessa~y to define the technrcal and opcratronal requrrcments seagolng operalrons w~tha manned vehrclc wrll be needed rf of the p~opulslonsystem Likewlse the lelatcd mcchanlcal and acceptable desrgns ale to be developed structural p~oblemscannot be defined wrthout such studres It IS ag~eedthat a successful CAB des~gnmust embody fo~e Thus it IS desrrable to rmplernent fu~the~studies at an early and aft sk~swrth whrch to contarn the bubble, and these wlll date have l~ttleclealance at the watelllne S~mplecalculatrons show P~opulsionsystem development wrll be iequ~ledfor a la~ge that for operatron In a seaway at speeds up to 100 knots scale test vehrcle as well as fol the ultimate des~gn The the potential water loads on such hlnged, but otherw~sestiff eslrrnate lor the time requlied states three yeals for the large skrs ale enormous In add~t~onto the ~ntolelablestructural test vehrcle and five yeas for the commercial slnp Srnce des~gn loads, larger fore and aft accelerations would be Imparted to studies can be callled out at ~elatlvelylow cost, rt 1s desr~able the claft To avord such undesirable loadmg, a flexlble balloon to Implement them as soon as poss~ble type of sk~suggests rtselt, but agaln thc desrgn loads are unknown at thrs trme Save for the employment of flexrble Hull Panel Report fabr~cskls, the qual~tres of wh~chale unltnown, no othei The Hull Panel plepa~edthcrr own repolts coveling all the plomlslng avenue of approach to skr des~gn has yet been ~mpoltant aleas, but because of the l~m~tedtlme ava~lable advanced they emphasrse that these wele of a prellmlnary nature They The panel ag~eedthat sk~des~gn iepresents a niajoi problem clltlcally reviewed the st~uctuialwerght est~matesemployed alea which must be completely solved before selrous develop- m the Booz, Allen studies and the methods by which they ment of CAB vehrcles can be undeltaken The practicability were obtalned of the entlrc project may well hlnge on whether reasonable The conclus~ons on these est~n~ateswere as tollows solutrons can be found 1 Fol a 1,000 ton gloss welght CAB designed a~ounda A p~ellmlnaiystudy shows that the alumrnrum alloys hold bubble plessure of 138 Ib/sy ft (674 kg/sq rn) and con- the most ~mmedlatepromlse for usc on the prlmary structule structed ol alum~rl~un~alloy havlng a 39,000 1b/sq ln Alloy 5456 has been used wlth conslderable success In mallne (2,742 kg/sq cm) yreld stlength, the .;tructural we~ghtIS environment Hrghel sttength alloys and steels may well estrmated to be a~ound35 to 40% of the gloss welght allow aubstantral weight savlng 2 Fol the range of SES between 3,000 and 5,000 tons and Plcsent concepts fo~the CAB hull entall a large box-lrkc wrth the bubble pressure rlsrng as the cube root ol the st~uctuleglving the maxlniurn of lnte~nalvolume for cargo we~ght,it 1s ant~c~patedthat the percentage wrll remain stowage The ptoport~onsof the box ale so la~gethat a very as in 1 above plonounced degree of shea~ lag as well as othe~stluctulal complical~onswould have to be cateled for Moieovel, in the "S~nl~la~ly,by the end of approx~matelytwo mole yeas and displacement cond~t~onthe CAB resembles a catama~anwlth w~than expend~turc of an add~tional srxty mllllon dolla~s, a long span between the hulls The buoyancy provlded by the appiox~mate quantatlve values could be dete~mrned Cor the skegs is of the ordel of the vehlcle's displacement Reseaich plelin~inaiyengineeilng design of commc~ciallyfeaslble ocean w~llbe lequlied to clallfy sevelal ol the essential st~uctulal t~anspoitation systems 11 ~nsurmountabletechnological plob- mechanisms lems appeal to exlst, Lhey probably wlll be d~scove~edea~ly After levlewlng the need lo] ~esealchInto labi~cswhich In these studlcs and the programme could be teimlnated seem to offel lhe only way to successful sk~deslgu, (he panel "If the leseatch proglamme plovldes a pos~tlve~ndlcation then mentlon the need for resea~chInto the devgn needs of that comme~clally compet~tlve pel Foimancc can be achieved, such skills. Statlng that exper~menlalwork w~llhave to be a contlnulng plogramme wlll be lequlled involving laiger done to arrlve at a design that will perfoim well at 100 knots resca~chcraft (of the older of 500 long tons) in ordel to Problems c~ucialto the hull of SES concepts ale I~\tedas determine perrolmance data w~thin acceptable englneelmg Dynamlc loads and acceleratrons tolerances This extension ol the ploglamme would involve Overloading sea cond~t~ons,damage and stluctural fallule an inclcased funding rate as compaled to the calller efforts' Fole and aft skis Fabrlc for pliable st~uctures "A one rnlll~on dolla~expenditu~e Coi fiscal year 1966 1s On Lhe subject of development progiammes, they endo~sethe co~lslde~edreasonable In the light of the usual impediments to need fol an actlve proglamme, but untll mole supporting initlation of a new erea arch programme and because the fitst technology IS available fol englneellng purposes, it should year's wolk woilld be executecl with ava~labletalent in exlstlng be on the basls of lescalch and advanced development They facll~ties This amount could glow leasonably Lo two or th~ee are also of the opll1lon that the CAB concept IS not yet ~cady mrll~on dollars 111 fiscal yea1 1967, reachlng a total of ten Tor Contract Defin~tlon action m~lllondolla~s In the fiist three yeals " Operations Panel lPepost Notable volds In the Booz, Allen assulnptlons relating to The repolt glves a vely good insight Into the ~ntrmate the economlc analysls were ment~oned and exception was details ol Amellcan plogrcss rn the overall field It IS clearly taken In the case oC others Detalls 01 the laltel ale llsted seen that several doubts ex~stabout the plesent capablht~er 1 The ldentificatlon of SESOC suppol t fac~litlesas a pet- of the11 craft such as they ate Anothel pomt i\ the extremely centage of dilect operatlng cost 1s cons~deled inappro- ludimentaiy and ea~lynattue of so many projects All thls prate It should be consideled as an indilect cost makes the 5,000 long ton des~gnmole a figment of ~maglnat~on 2 The stated utrlisat~onfigule of 7,000 hours per annum rs than a long te~menglneerlng pioject unrealrst~c From expellence w~th othe~ structures of Slnce thls 1s purely a commerc~al appral~al,the thoughts slmllal type d6wngladlng to 5,250 houis, a 2576 reduc- on l~nesof development In the mll~ta~ysphere remaln un- tlon, 1s cons~deled leasonable Thls lower level of known Significantly the report makes no plovislon fo~In- utilisatlori would lequ~lea propo~tlonatelnclease in the foimat~on~nputs coming fiom millta~ysoulces and assumes fleet slze that the ent~ieploglamme wlll be clv~lFrom beglnnlng to end, 3 The assumption that equipment lequired fol coll~sion apa~tfrom possible naval ald in assessmg the qualit~es or avodance is withm the state-01-the-all 1s not completely large test cr aft concurred wrth A flnal solution would lest In a com- Their lack 01 support fol the periphelal alr-curlam type IS poslte approach consisting ol Lhe use of rada~,visual notable and it could be that the11 leasons for this are sound delectlon, establ~shmentof separate sea lanes and speed The problem of adequately cont~oll~ngsuch types IS st111 reducllon when crtcuinstances or conditions dictate it p~oblemat~caland thls po~ntis well appieciated In th~scountly It IS also thought that the home-polt termlnal should have The BHC Hoverficlghter design project of 4,000 tons was qu~ckactlng dl ydock facll~tlesoi a nlallne ailw way for frequent almost certainly prepaied, or at least ieleased, In answer to lnspect~on and lepall of the undelwatel structure Also the leport In so marry ways ~t hlghllghts the advanced nature elaborate and well stafled mechanical and clectlonlc lepall of Brltish development, but 11 would be unwlse to shout too shops w~llbe requ~red The out-port teimlnal should also have loud Even by our own standards ~t 1s extremely premature the same facll~tleslo1 inspection and 1epa11 In addition, the and 11 would be lmpossible to convlnce a ctrstomer without leal estate fol the ploposed new termlnals will be dlficult to going thlough two mteimedlate stages represented by craft of plocure and expensive The area, when found, wlll have to a~ound500 and 1,000 tons These alone would leq~iirea tlme be served by road and call selvices scale of at least five years High capac~tyluel bunkermg systems wlll requ~rea hlgh first cost as well as high operatlng costs due to the haza~ds rnvolved In thls d~lectlon fast loadlng rates would have to be p~ovided Loadlng 2,500 long tons of fuel having a density of 6 4 lb/gal (le, specific glavrty 0 64) ln an assumed loading t~meof ten hou~sreyulres a loadrng rate of 1,450 gallons pel mlnule Load~ngat this rate at a t~mcwhen no ca~goIS being handled would glve a total delay of 18% of an aveiage one- way t~lptime A fifty-five-hour one way tllp has been assumed Conclirsiolls and liecommendatioras In the final summlng, the main SESCO Commitlee make ~efeienceto bas~cpolnls laised by the techn~calpanels They endorse the maln ones whlch lelate Lo future development and how ~t should be dlrected both t~meand finance wlse If the report IS adopted and acted upon, then the followmg ~rnportantpassages from it will g~vea clue as to the scope, purpose and t~m~ngol an active pioglamme "An improved state oT knowledge fo~the solut~onof cruc~al technolog~cal problems can be ach~eved~f immediate studies cmphas~selesealch rathel than development of scaled ploto- lype vehlcles By the end of about three years and with the expendltule of about ten million dolla~s,lt would be possrble, Bvitisl? Novercvnft Coi,pomtion3s 4,000 ton watev-propelled hoverfreighter. disposcihlp locid 2,000 lons; Length overall 460 fl; Hen117 144 ft; FIright through a coheiently o~ganlsedresearch proglamme, to know 70 it: Po~~rrulnnteizht 18.500 .sl?n Uvistol Siddelev Oli,r~~orrszns trrvhines: whethel the SES concept is techn~cdlly feas~ble fo~ocean Mnxiwluw~ coirtinuorr> cnlwr IIUIP; speed 50 111?o(.s; ~nrlumnc'e 10 hours; Typical load sixty-fouv 8 ft x 8 fl x .10 fl conlairreis to o tolul of 1,600 operation tor7.s gro.s.s; Loads stou~erl in eight holds, eight contnirzer:~ to n hold The Dolphin, designcd in ilze Urlited Stater by Gruwzrnarz Aircraft, und constructed by Blohm oad Vors in Homburg, wu;, ofJlczully christened "Corsorio Neglo" on August 20tlz, 1966, and handed over to Muritirnu Antures, the Spanish sl?ipping corn/~unywl~o will operate tlze craft in the Curzury Islands

a hydrofoi comes to ife in the B ohm & Voss shipyard

Subcontractors and Suppliers Geiinann Ehlels, Hamburg sea-water pumps, Tuc ext pump, Rexroth GmbH, Z oh1 /Main hydldul~cfitt~ngs b~lgepump Hydro-Control GmbH, Hahn/Oldbg steer~ng system Anton Kaeser, 2Iambulg all-conditioning plant F ik Sening, Hamburg fittings Aug Neldig Soehne, Mannhelm gear pump Maschlnenfabirk H Schmidt, Hambu~g hydraulic cyhndc~s Westrnghouse, Hanovel complessed-air system Deutsche Shell, Hambu~g lubo~ls Vickels Hanover-IClrchrode hydraul~c pumps, hydromotols Giesse~e~Sande GmbH, W~lhelmsh~venalloy steel castlngs Endress and Hauser, Hambulg level rnd~catorslor luboll and Freon lire ext plant Walter K~ddeGmbH, Lueneburg l uel tanks Bau and Montage GmbH, Hamburg struts I G E Lineta, Hambulg ds-genelato1 Gruenzwe~gand Hartmann, Harnbuig valious insuldtion wolk Zoellner & Co, IClel-Gaaiden slgnal system C Haacke and Soehne, Hamburg alu-pipe connections Atlas-We~ke,Blemen depth ~nd~cator,radar system Teleflex GmbH, Herligenhaus Teleflcx remote cont~ol AECi SchiAbau, I-iamb~~rgstalter generalors Gerll~ig,Holz & Co, Hamburg nitrogen bottles E-Motorenwerk ICalscl, Hamburg elech~cmotors Stratofiex GmbH, Blemen * flex hoses Elbag GmbH, Wersel-Loreleyk~ers l~mltswrtches Pellw~tzOhg, Hamburg alu-fittings Bosch-ve~trKluse Nachl, Hamburg staiters and aux battcrles Boll and Klrch, Icoeln-Ehr enleld filteis SSW, Flan~bulg electi~cinstallatron Hellel CimblI, Wuppertal-Elberfeld shut-off valves Debeg, E-Iamburg r adro telephone Seer1 ut ilze clzristerzing of llzc Grumn7arz Dolplziti. From left to right: W.J. lJattisorz, vice-presiderzt of tlie Garrett Corporation, world- wide distributors uizd sctles agents jor ilze cruft; Murques Tuurisuno, president Maritima Arzicires; Mur- quesa ?'aurisuno, ~jlzo acted as "God-motlzer"; His Excellerzcy Jose' de Erice, Ambassador of Spoin to West Germclliy

Rolls-Royce, Delby gar tu~bine Gal ~ettCorpo~dtlo~l dut~p~lot Genelal Motors, Antwelp d~splacementdiesel, auxlllary d~esel Buehlel Corpoiat~on,Ind~anapol~s marn transrn~sslon ICamewa, Kr~stlnehamn,Sweden controllable-pitch plopellel Llonell Pacrfrc actuators Palkel-Hann~finNV, Holland filt~ngs Alcod hydl ofo~ls

Mr Javier Frarzces, the Gurz- is11 cuptuitz of the "Corsar io Negr on, recn briefing some members of his crew. Mr Frcmces, ~vllo lzris hrtd lwo yert~s' ewperierzce in the hydro- foil field soid thut "tlze mugrzi- /?eeizt consliuctior? of tile cruft wns n mujor ctdvnrzee over crrzy- thirzy of tlze kind ke Izad ever ~eert" The vessel profile crnd weatlier deck ljlutl. Clearly desigized to be a tugged sea-yozng vessel, the Dolphin llrir (I very adequate ~vorlcir~gdeclc uret-i and (1 converltioi~ril ctitwt~l/c. The nuxilicrry propulrioii unit:, ~ho~tldgive good low-rpeed mcrr~oeuvrubility even in high wirlds. The absence of tiny jelzdeting is surprising, cind presumcil~ly special bertlzitzg facilitie~ rvill be provided. The funnel has bee17 provided lvith (117 tier-oJoil device to ensure thot erli~ustfllmes nre scvept ivell elerrr of llle vessel

Dolphin Technieal Data Main Engine Ma& Puyloc-rd Mtrx Fuel One Rolls-Royce Manne Tyne Malk 621 Payload 8 2 4 7 Max~mumpower 7,500 hp Fuel (~ncleserve) 3 8 7.3 Clurse power 3,160 hp Gross werght (d~iplacement) 60 0 metr~ctons

Raneew (N\ nnles) 200 400 Auxiliary Engines Performance Two Genela1 Motols 6V-53N d~eselcnglncs of 216 hp each Takemoir sneed 25 knot? Crulse speed 50 knots Dimerlsion~ Fuel consumpt~or-i 7 15 gallNM Length ovesall 75 " Nullborne speed 8 knots Length of hull 66 ft Fuel consumpiton 1 23 gal,NM Ream of hull 18 ft 8 in DlaPt, foils retlacted 4 2; Seaworthiness Illaft, forls extended 13 ft 5 rn Seastate 3 Fuel tank capac~ty 9,000 llt Wlnd velo~lty 17 knots Wave he~ght 3-5 ft Tommge Manoeuvrability Gloss 83 Turning Radius, fat turn 760 ft Net 52 coordinated 840 ft Weights Stopping dlstance from Operating weight empty 48 0 melrrc ions 50 knots 450 ft (ci) The passenger declc, sholving nccommodritiorz lcryout, ivheellroure crud toilet facilities, N~JOthe muin pr opulsion er~girie afzd sterrz strut retrartiorz gear, The twin pcissetzger access points 012 eaclz side will multc for quicker turrl-rourld arid greater ut~liscitio~ioj tlic vessel

(b) Tlze belorv deck spcrce devoted to the auxiliary services; the jet propulsiorl units, the G.M. Diesel engines, sewage disposal equipment, fuel tcmks, forvvard strut retructiorz gear, air-coaditiorzirzg plorll arzd the criixiliclry diesel geiler,ating sel

(ci The vessel seer1 from for.~)ard,slzowing the low frorztul area of the ,strperstructure rrrzd the 22" deudrise of the huli

A glimpse of tlzc starboard side General Motors auxiliary ~lze~olls-~o~ce Marine Tyne propulsion ewine installed in pr.(~pulsionengine. These u17itS, ~~arli~~~larl~light ill weigl~t, position, seen here through the air intake opening at tlze ,.,li,bl, a12d economical, ,,Tovide tl,e with il useful after end of the superstructure safety mrrrgin and a good range under all conditions

P

Tlze auxiliary diesel generating set. Careful atlentiori to The control con,\ole during co~~struclion;usscmbly and testing ii~strrlled iveights i~ revealed by the markings on the unit of some of the equipment The framea)ork foi the support of the tern strut retraction pivots before incoiporetiai iiito the traitsom structure of the rhe upper end (I/ the stern strut and tronsmissior~ during vessel k~~sembly011 the tiansom of the vessel. Thc blaclc box in the centre houses the top Jet of bevel gears. The trnrzsverse retruc- tion oivots are at the tor) of the assembly on either side and orte of the vertictrl steering pivots can be seen between them

The r,ivoting part of tlze stern strut. Compare this with tlze A stage ilc tlze co~zstructioi~of the stern strut. Tlze shaped adjoilzing part including the gear box shown above. Tlze steer- skin is secured to the fabricnted framework iiz preparation for ing actuator Iinkcrge can be seen projecting to one side a1 tlze riveting upper (near) end The cast and fnbricated framework of one of the forward A iiie~!of 111~for~iard strut retraction pivots. Soon the corn- rtrutLs. At the far end is the bolted firInge co,lnection to tl?e 17leted struts will be assembled 07% the liull arld the complex up,,,, fnbrication lrzcorporating tl?e retrnctiol? pivots, and at retraction liizkages and hydrofoil control corzr%cctions in place llle rear end [he supports for hydrofoil

Complexity is at lust hidden behind aerodyrlcrmic simplicity The lower part of the for1vard struir completed. Tlze hydrofoil Water speed mccrsuring equipment and the l~icrter intalce can incidence confro1 conneclions appear to pass tlzrougk shrouded jusl be seen OM fl~estrut leading edge Tlze shape of the strut guidcs at the trcrilirzg edge. The support pivots for one of tlze top end and its slipporting slructure rvill cleorly cause some l~ydrofoilsand its crssocitrted pod are very clearly seen at the spray at talce-op, well clear, lzo~~ever,of tlzc wlzeellzousc rear end ~vindo~vs Lieutenant Commander G. E. Hammond RN Interservice Hovercraft Trials Unit Lee-on-Solent

I-IE HOVERSHOW at Browndown thls June, whether success- or the other, dependrng on whethe1 11 IS a seaman or an T I-ul as a spectacle or not, clearly lndlcatcd by the numbel alrman who glves ~t The seaman fo~getsthe speed involved of exh~bitorsalone, that the hoverciaft rs here to stay and ~f and the completely fore~gn dr~ftfactor and aero-dynam~c noth~ugelse, 1s becomlng ~ncieaslnglymole established as a control, and deludes himself that as there 1s wate~all around means of fast water transport hlm, ~t must be a sh~pThe alrman, more at home with the I have been asked to wl~tean art~cleon Hoveicraft Navr- speed and dr~ft,but bllnded by the brochure statement, "It gat~on Ovel a year ago I set about th~stask and p~oduced r~dcsabove the waves on a cushion of alr", settles for airciaft some Ideas on the navrgatlonal problems and rnd~catedthe and forgets that the wate~surface he so closely follows and type of equipment requ~rcdsafely to ovelcome them Much rs rnvarrably In contact w~th,IS a ha~dpein~ck~ty mlstress who has been done by cnterprls~ngfilms to produce such equlp- glves no qua~ter ments, and ~t now only requlres an oflic~alpolrcy to be estdb- The Amer~cans,for leasons of thelr own, have class~fiedthe hshed for productlon to go ahead at an economical cost hovelcraft as a shrp, and rrghtly or wrongly, the legislat~veball has fallen 111 the mallne court Presumably thew marlne regu- 1 would l~keto concentrate at this time on the human lat~onsw~ll be bent to accommodate hovercraft and they wlll element - the user or opeiator Let me say light f~omthe at least know where they stand Here rn th~scountry we are start there IS no "black art" rn dr~vingor nav~gatinga Hovel- strll experrenclng difficulty fitt~nghovercraft w~thlnthe Board craft; but the deg~ce of soph~st~cationof both craft and of Trade's marlne requirements and the Air Reg~strat~on equipment, coupled w~ththe h~thertounused environment, Board's av~at~onrequlremcnts, the lattei at present ale bear- lcquire a new m~xedset of sk~llswhich do not ex~strn any Ing the brunt In the leg~slat~onfield Now 19 the t~mefor both other srngle traln~ngor professlo11 It IS gcneially accepted to Integrate and foim a hovercraft leg~slat~vebody and let un- that nearly every facet of the Hovercraft, be 11 we~ght,power, prejudlced common sense prevall God forb~dwe Walt for payload, construct~on, endurance, etc, falls nicely between thc first serious acc~dentbetween hovereraft and sh~pbefo~e sh~pand allcraft Th~sfact holds good for the operator, drrvei the ca~dsare fully shown The thought of the two s~dedlegal or navrgator The alrman has a lot of seamansh~pto learn battle that would then ensue makes even the layman shudder and the seaman a lot of a~rmanshipto master Hovercraft manufacturers and operators naturally deslre to It 1s natural that any piofession, brought up and tralned keep costs down and must prune drastrcally if hove~craftare to an estabhshed and well tr~edset of rules, IS reluctant to to become commerc~allyv~able; but a blind, m~sd~~ectedeye seek or accept adv~ccfrom another hitherto allen profession cast In the operator's personnel, equrpment and tiarnmg drrec- If th~scountly IS to lead and show the Hovercraft way, theic t~onwlll prove vely expenslve In the long run W~ththe fast IS no room for the exlstlng petty p~otessionallsmbetween alr ratc of woild w~dehoverclaft development there 1s llttle t~me and sea, be ~t rn the dcslgn, productlon, legrslatlon, operatrng for tila1 and error, it must be ~~ghtfirst time before bad and 01 traln~ngfields The~emust be a genurne willrngness f~om dangerous habits are allowed to become doctrlnc Unnecessary both s~desto get togethe], glve then best and deal with hover- rules and regulatrons can st~flein~tiative, but a lax, unsule craft 111 the11 own r~ghtKesrtat~on in cstablishlng a comple- adm~nrst~at~onencoulages slack hablts and can be equally henslve hovercraft code, could hold back the tremendous disastrous L~kcanythrng worthwhile, hovermanship will not hovercraft potentral and damage the Image by allow~nga loop be cheap, but glvcn the goodw~lland the colrect balance of hole foi sharp pract~ceand garnesmansh~pto garn a foothold personnel, equipment and know how alieady exlstrng In the At present, 111 the des~gn dnd production field, l~ttlcto- seaman and allman professions a lot of sholt cuts are avail- getherness exlsts and the bias rs pelhaps too weighted on the able air s~de,resulting in the unnccessaty hlgh costs of aircraft Bclng a service man, I would not presume to know who type construct~onsand attendant lnspcctron standards These makes Lhe best commeic~alhovercraft operato~ I cxpect the high standa~ds, vc~ynecessary for a~rc~aft,could be con- ~uleholds good and the steamship opelator or allline opelato1 sideiably loweled for hoverclaft, but w~llneed amend~ngIn have the best chances of success prov~dcdthey ale piepaied such parametc~sas watertight rnteg~~ty,reberve of buoyancy, to take advrcc f~omone another When it comes to hoveic~aFt ctc, to comply wrth cx~stingmarine standards In the legislat~ve driveis/commande~s and nav~gatois,the iule ce~ta~nlyholds field also, mole emphasls on the marine standards of opela- good, and provided the alrman rs adaptable lo the way of t~on,ilavrgation and t~aining wlll be nccessaly before the the sea and fhe seaman has the necessary apt~tudeand antler- collect hovercraft slot is found IJnt~lth~s is firmly establ~shed pat~on foi the c~aft's h~gbspeed and aerodynamic contiol, opelators and would be tra~ningestabl~shments can have no both have equal potential Havlng seen the basrc seamansh~p set standaids or plogiamme to work to clrois pelpetrated by hovercraft drrvers from an alr back- Is ~t sh~por a~~c~aft?So many lrmes th~squest~on is ground and the equally glarrng airmansh~pboobs made by laughrngly asked, and the answel IS lokingly given one way their counterparts horn a sea blckground, the cleglce of cross pollination is clearly ev~dent Given starting qualificat~onof the seaman and the Ailman have much to lealn The inost eithei a civrl ailticket or a maiine mate's ticket, there is an plactised marine navigatoi who kiiows h~siadai well will exhaustive list of subjects which requi~eto be mastered Most still find the hoveic~aftspeed and dilft factois veiy new and are, In vaiying degrees, common to one profession oi the difficult to deal wlth Given even the most sophisticated other, but theie ale seveial which ale very new to both Added equipment, a lot of actual expelience IS requlred befoie the to this, experience in the job w~llpldy a laige pait p~ctuiefalls into place and tbe correct lntelpietatlon can be On the subject of hove~craftnavigators, 1 must fiist ieturn made This veiy iiecessaly experience 1s time consuming In to my oiiginal chatter - Hovel craft Navigation I ain con- craft operating hou~sand could best be gained ashoie 111 a vinced that except in the case of veiy short congested ioutes sultable hoverci aft radai simulator the lendency towards directing the hoveiciaft from a shoie This leads to the subject of hoveiciaft commander/driver base is a bad one, unlike aircraft direct~onwhere the glound and navigdto~ training Theie is an uigent need foi stan- d~rectorhas commuilication wlth and contiol of all craft in daldised training both EOJ the servlces and commeicidl his aiea, the hoveic~aftcontioller ashole has the unenviable operators The syllabus must be caiefully prepared and the task of tiying to di~ecta few claft thiough a maze of inde- deg~ee of proficiencq clearly laid down In ot dei that graduated pendent unknowns whose coulses of action are totally un- hovermanship ticlcets can be attained Theie must be nothing predictable, he has no safety lanes to fall back on Should a haphaza~d about this -a ticket musl mean something and collision occur undei these ciicumstance.;, the mind boggles be able to stand up 111 court on 11s own merits It will need when the question of blame is thought about The navigational the backing of a basrcally marine licencing boaid At the data must therefole be available in the hovercrall foi the com- prescnt state of the art ~t JS unlikely that any single se~vice mandei to assess dnd act upon In the tight situation this data 01 commerc~alentcrpiise could find the necessaiily expeiienced w~llmainly deiive fiom some foim of iadar, be it tine motion staK to set up a woithwhile and ellicieut hoverciaft crew or ielative stab~lised,fitted 01 not with ciaft track llldlcatlon tiaining school Such experience does exist fa~rlyevenly dis- and an optical navigational attachment The growing tendency ti~butedbetween the services and commeice and the hme is foi the hovercraft navigator to double up as the second ripe for Logetherness lo take a furthei step with the setting pilot/drlvel is a good one I am sure that the be~tplace fo~ up of a joint tiariiing scheme with equally distributed financial the hovetc~aft captain to cxeicise his command when In support and some min~itrybacking Theie is not enough t~me, congested watels at n~ghtoi rn pool vislbillty, IS f~ombehind ~f we ale to maintain oui hoverclaft lead, to fuss too much h~sradar about whose ensign should fly fiom Lhe yardaim, but we It IS in this field, of hoverciaft ~adaiappreciat~on, that both must make su~cthat the Union Flag iema~nsat the masthead

THE STORY OF R CUSH

LESLIE HAYWARD

KALERGHI PUBLICATIONS

U.K. and Europe 5s. 6d. (incl, postage) Canada and the U.S.A. $1.25 (incl. postage) Figure 85. Yoichiro Kunbe

(Part XI) ie Hayward

wo recent catamaran hull type of hydrofoil vehlcles bullt for the Ofice of Naval Research durlng 1958, and T are described In Aritrsh Patent 1,007,567 and US fitted wrth supercav~tating€0119 and a supercavltatlng pro- Patent 3,227,123. The Br~trshpatent granted to Yolchrro peller, attalned a speed of sixty knots powered by a marine Kanbe of Sokashl, Saltamaken, Japan, ~llustratesa deslgo turbine englne rn whlch twin hulls are spaced apart and rlgrdly joined Hydrofoil k~tssuitable for "do-~t-yourself"installat~ons together by surface decklng A serles of hydrofo~ls,each on fourteen to slxteen foot outboard runabouts were for1 berng longer than the beam of the craft, are supported marketed dur~ng1958 and enabled speeds up to thirty-five from the hull structures Part of the support structure knots to be attalned These krts were manufactured from actlng as one leg of a "V" type fo11 The t~pportlons of aluminrum and it 1s known that more than 200 were sold the fo~lsare retractable wlthin the maln tolls to facll~tate to the general public docklng. In 1960 the Un~ted States Manne Admlnlstratron Auxrl~aryfolls rlgrdly attached lo the hull beneath the awarded a contract to Grumman for the deslgn and con- water line are arranged In staggered rclat~onshlpw~th the structlon of the hydrofoil ship Denison. The craft, an maln foils Propulsion 1s achleved by screw propellers ol erghty-ton ocean research vessel, was launched in June hydraulrc jets. 1962 and has operated at bpeeds In excess of sixty knots Unlted States Patent 3,227,123 ~ssuedto Hellmut R A 320-ton 212-foot craft has recently been commlssroned Vorgt of Sun Valley, Californra, relates to a catamaran for the US Navy. type craft surtable for towrng on an automobile trarler The Dolphzn, bullt of special corrosion resistant alloys, for transportallon purposes. A marn surface plerclng d~he- IS a 75ft craft designed for the commercral operator dral foll, located near the centre of gravlty of the craft, Havrng gross tonnage of approximately eighty-three tons, is rlgldly connected to the hull and d totally submerged the Dolphin IS desrgned to carry nrnety passengers or foll 1s pivotally attached to the stern. The angle of attack 19,000 1bs of cargo and a crew of four, over routes ex- of the rear fo~lis automat~callyadjusted wlth respect to tending to 200 llautical mrles at a cruisrng speed of fifty speed, load and water surface condrtlons by a mechanl- knots. Power 1s suppl~ed by erther a single or twin gas cally actrng senslng devrce whlch follows the water surface turblne engrne and twrn dresels are rnstalled for hullborne m front of the craft A manual control over-rldes the operations at spceds up to ten knots. The two fully sub- automatrc control as necessary merged torward folls providrng 701% ot the 11ft are hydrau- The Amerlcan firm of Grumman entered the hydrofoil lrcally retractable and may be stowed 111 the overhead field about 12 years ago and acqu~red the research position. The srngle rear foil 1s combrned wrth the rudder organlsatlon of Dynamrc Developments Inc. durrng 1956 and propeller pod The first craft produced was the XCH-4, bullt for the A recent Arltish venture whrch merits considerable Ofice of Naval Research rn 1955. Powered by two air- Interest 1s the desrgn put lorward by Southern Hydrofo~ls craft englnes with air propellers and fitted w~thladder L~mrtedof Southampton Sea Ranger hav~nga drsplace- type forls, thrs elght-ton craft reached a speed of seventy- ment of 7: tons, provldes a hrgh performance craft usrng eight knots and establrshed a new world speed record for fully submerged forls controlled by mechan~callyoperated hydrofoil craft The XCH-6, a small research craft, also predrctor arms Glass rernforced plastic 1s used for the LH"RMED PATROL. PASSENGER

Hull length. 30- 0 Hull beam. 15'- d Draft, foils down. 8'- 4' Draft. foils retrccted. I' - 7" Cruise speed.35-40 knots, Take-off speed. 20 knots. Speed. foils retracted. -I0 knots. Disposable load.- 5400 l bs(2500 kgs) Displacement. 74 tons Diesel engines. -2 x 190 b.h.p,

Figure 86. Sea Kcu~ger

hull and superstructure, grvlng freedom from corrosron, ~notlvepower for foll lnc~dencechange Pred~ctorarms, low ma~ntenance requirements and ease of repalr. The travell~ngahead of the craft, "measure" the waves, and stern gear of the Sea Ranger util~ses"Z-dr~ve" unlts whlch lhe~r movements are transm~tted, mechanically, to the permrt the use of propellers givlng d~rectrather than angled ma111 fo~ls.So that the craft does not react to small waves, thrust whrch delays [he onset of eroslve cavltat~oncon- over wh~chthe boat can fly level, filter heels malnta~nthe d~t~ons.The propellers have two prtch positions, one for predrctor arms at some he~ghtabove the water; move- take-off and one for cruise, thus permltt~ngthe best posslblc ments of these heels have no effect on the heavrly-damped use of ava~lablepower All struts and foils are hydrau- arms llcally retractable, but In the down pos~t~onall the folls Through a mechanical-hydraulrc Ilnkage, the p~lotcan are wlthln the beam of the craft, enablrng dock~ngto be Intervene In thls automat~csystem to regulate flylng he~ght, accompl~shed w~thoutfear of danger to the underwater to bank for turns, and to effect take-off unlts. The predictor arms serve another useful funcl~on,iot Fully submerged fo~l systems requlre accurate and provrded for In clectron~callyactrvated systems In the sensitwe controls to marnta~nlevel lllght In the narrowly case of rap~dfl~ght over confused seas, there IS always ~estr~ctedzone above the water In which the hull they a danger of the momentary surfac~ngor near surfacing support muyt travel Modern electronic a1d4 can provide of a foil, and consequent loss of lrft (a "sea crash") The such controls, but they lend lo be costly to Install and to Spa Runger'r predlctar arms carry folk wh~chprovlde malnta~n Southern Wydrolo~ls' solut~on to the control emergency l~ftIn such circumstances, and tests have shown problem IS to use the water surface rtself to provlde both that, on nearly every occasion, they re-establish level flight altltude and wave he~gllt-and-shapedata, and also the before the hull touches the water Hull WL.length 41' - 0' Hull beam 24' - 0' Draft, foils down.13'- O'approx. Draft, foils retracted 4'- 0" approx. Cruise speed 40-45 knots. Take-off speed 20 knots. Disposable load. I8 tons approx . Displacement -- 44 tons. Gas turbines,rnain-2 x 1100 s. h. p. auxiliary-l x375 s.h.p. Figure 87. Oceai? Ranger

The Sea Ranger has been designed to be as versatile as vides simpler, removable seating, large rear entry and space possible, for use in a great variety of duties, and wide for cargo. In addition, Southern Hydrofoils have designed variations of passengers and cargo loads (and also of specialised patrol boat versions (armed and unarmed) and operating range) can be obtained within the vessel's overall an emergency vessel, designed to assist in routine and disposable load of 4,200 lb (2,000 kg). The "standard" emergency ambulance and sea rescue work, equipped with version is a 21-seat passenger boat, equipped with roomy medical facilities, including stretcher beds and emergency comfortable seats, generouq luggage space, and toilet operating equipment. and also with standard rescue and facilities. The "tourist" version has greatly extended win- fire-fighting apparatus. dow area, transparent roof panels, and seats for 25 passen- Powered by two General Motors 6.V.53 diesels, Sea gers. A crew-and-equipment-transportation version pro- Rnnger is expected to have a cruising speed of forty knots .- 120 PASSENGERS,

Figure

In the fully loaded cond~t~on.A Dowty jet pump unlt rs has a hull length of 51 ft and a drsplacement of forty-four Installed for aux~lrary drsplacement condrtrons and for tons Projected power unlts are Solar Saturn 1,100 shp shallow draft operation when the struts are retracted turboprops. The three fully submerged forls are of swept-wrng plan Let us hope that suffic~entbacklng and ~nterestw~ll be form and are constrtuted of solrd alum~nrilm alloy, pro- forthcomrng to enable the first Br~trshpassenger carryrng tected by a plaster coatlng. hydroforl craft to go ~ntoproductron. Ocean Ranger 1s of s~mrlardesrgn to Sea Ranger but e Notes on the Stabi ity of Hovercraft

by our Special Correspondent

A two-day seiles of lectures under the genela1 heading of piling his paper. As an entry, the point was made that the "Fluid Control - Componeilts And Systems" lncludcd a papel subject was chosen to show something of the larger scale use ent~tled"Stability and Control of Arr Cushion Hrgh Speed and application of "Fluidics". Thus it did come within the Glound Veh~cles" Ar~anged by the Adv~soiy Group foi general scope and theme of the lecture series. Aero~paceRcsea~ch and Developmeilt (AGARD), the lectu~cs were repeated in Turln, Brussels and London Responsrbll~ty Concentrat~ng malnly on the pioblems of suspension, fo~organlsrng the London sesslon lested wlth The British M Giraud made a few obseivatrons of a ve~yfundamental Hydromechanlcs Resear ch Association, wh~chhas headqualtc~s natuie He drew attention to the fact that hovercraft gave rise at Clanfield Over 100 people were in attendance 111 the Physrcs to lowel ground pressures than most othei thrngs includrng Lcctu~eHall of Impei~alCollege, to hear M Gi~auddeliver man, current cush~onplessuies plevailing (Fig 1) Also so far his papcr Thls was p~obablythe first time that Fiench ex- as most vehicles ale concerned ~t is accurate to assume that perrences had been ]elated to an Englrsh audience the supportrllg surface is rnfinitely st~ff Such a s~mplestate As Scientific D~recto~of Beltin & Cle, thc author was of affalrs does not ex~stfor the hovelcraft, whrch follows a obv~ouslyable to draw upon a wealth of cxperlence In com- t~ajectoryThe tracked type of vehicle is paiticularly ~nfluenced by the stiffness of the hack, so that thrs and the hoveicraft's arr cushion must be considered as an integral pait of each PRESSION MAXIMUM DE CONTACT, othel In fact, it appeals [hat p~acticaldes~gn and evaluat~onhas to sta~tat this very polnl If the t~ackIS too stiff it w~llbe MAX I MALER AUFLAGEDRUCK., too costly, whrle a highly elastlc tiack would have undesirable characteristrcs Therefore, the distance between suppo~tsas MAXIMUM PRESSURE OF CONTACT. well as the scantlings of the cioss section and the type of constluct~onbecome an Integral part of des~gnand operatronal economics Another polnt dealt w~lhconceriied the power expended in opeiat~on by a number of different veh~cles, lncludlng the hoverc~afttype Curves showing powel cxpenditule in terms

PUISSANCE SPECIFIQUE DE PROPULSION SPEZIFISCHE VORTRIEBSLEISTUNG

i( KW/T- SPEC1 FlC PROPULSION POWER

Truck m votlures Cars

Figure 2. This set of curves shows power expended in terms of liilo~vuttsper tonne plotted lrguinst speed. The wuy the Figure 1. This representation of contcict stress demor~strntes hovercrtrft regime bridges the speed-power gap between the vrry unique positior~occupied by hovercra)'t ivheeled (wd winged vehicle\ is notnble UTE- FORME A CLOCHE Pdi~gance Spiciiigue en Fo~ct~ande la Hauteur de Fu~te

LUFKISSEN - PLATTFORM Speztfische Lerrtung ais Funktian der Spalthohe

-AIR- CUSHION PLATFORM Specific Power as Function of Leeckage gap

Piage de preisiom spa ~rit;.er s plies Figure 4. bereiih der ublichei .sel .isc"en Crucke T~votyj~icnl fuyerc cirrangrn~cntscorlsidered in M Girclud's lectu?e. The urralzgenzelzt ot, I11e lrjt hcls a spring Jsual iaiues af sp. if,- prr~s-c loaded leukoge grrp clnd the cztrungemerzt orz the light employs ' 1000 a 2000 ;a [L 0' a - 1 aim, Ijelloiv folds Inerensi~zg pressure extertds its dinrnetcr crnd lclzgtll

the authol telrned a "~tiffness balllei" at about 200 kmlhr Chardktercs~i~acne? Ma, ' -e (124ml/hi) Whilst iuilnlng tliey had the Impression that Chsrati6riiiie of a mar contact was being made wlth the gulde ra~lSmall wheels wele added at each end of the guide pads to plove IE lhls was so In fact it was found that the wheels wele not In contact and it was concluded that the st~ffnessof the pad system was too hlgh The ploblem of how to Increase the natuial frequency of the suspenslon and stabll~tysystem iemarns to be solved Des~gninvestigations have shown that a maximum Lrack deflect~onof one hundledth of the distance between the sup- Figure 3. Power expenditure in terms of kW/torzne is u li~zear polts glves a prachcal complomise between all confllct~ngle- ju~zctiorz of the leulcage gap accordirzg to this grrrph. The full quiiernents In any case this 1s currently being used as a yald- line presumubly repreJeltts Bertin experie~ace stick and the same palametel 1s be~ng employed for the straightness of the track For a full slze vehlcle accommodating of Kw/tonne weie displayed and ~t was seen that the hovel- about seventy passengels and hav~nga length of some 25 m ciaft lles, as expected, between wheeled and w~ilgedvehicles (82ft), a mlnlmum tlack culve radius of 16km (1 m~le) 7 h~sIS shown in Flg 2, wh~leFig 3 shows the powei expen- would be suffic~ent In the case of the test vehlcle, nolmal d~tuleas a funct~onof leakage gap accele~atlonsof aiound 0 25G have been expeilenced wlth a Next, the phys~csand mathemat~csof the tuyele type sup- soft suspenslon and 0 35G w~tha hald one It is thought that poit pads weie dealt with and numelous examples wele ~llus- figu~esas low as 005G can eventually be attained wlth a trated dlagiaminat~cally Our FI~4 shows two typ~cal soft suspension examples, that on the left exh~b~t~ilga sp1111g contiol of the The Aelotialn employs a 250hp Continental aeio engine gap, whlle that on the rlght employs a bellows type of con- fo~plopulslon and two 50 hp englnes to power the com- stiuct~on With th~slattel type as plessule incleases, the plessors The thiee blade val~ablepitch alrsclew has a levelse diameter and length also lnclease and thls 1s necessaly Sol p~tch~ange to allow back~ng,although a tun-table at the end stab~llty of the system If the folds wele In the opposlte of the track allows the veh~cleto ietu~nat high speed Thele dl~ectionthen contiaction would result and this would he ale three methods oC biaking; levelslng the piopellol thrust, undes~lable wooden blocks clamping on the guide la11 and deflat~onot Accord~ngto the Beltln ph~losophy,tlie leakage gap should the cush~onfol a leal emergency stop This latte~method had be of the oldel of 50 mm (2 ~nches)lo1 tracked vch~clcsand to be employed once and a decelelation of about 0 5G was always ailanged to glve a contiacting flow It IS thelcfole expel ienced w~thno appa~entdamage cons~deledas a contract~ngolllice It has been found that the Asked about the compalat~vepelfoimance of the Beltin natural flequency of the tuyele systein is aiound 5 to 6 cps .;uspension and the Hoveipad developed foi the Biltish Hovel- dnd that tlirs is too stiff It 1s the~eforenecessaly to add some l~a~n(HC & H J~me/July66 P 9) M Gi~audmade an inteiest- pneumat~celasticity to the system Ing comrnent He thought that the Beit111 system of lely~ng The Aerotrain cnt~relv upon all cush~on suspensioll for speeds up to 100 km/l~iand may be hlghei, was the better It ofTeled the F~omth~s po~ut the papel dealt with some of the ploblems least complicat~on,lowest powel expenditule and hence bettc~ as5oclatcd with the Beltill Aerotialn and expellencec, from opelat~rigeconomy ope~at~onof the quaitel scale veh~cleThls utillse\ foul Intel- It appeal& that the11 method will be used on the full scale conne~tedIcv~tat~on pads and Lwo fulther pads to glve stabil~ty vehicle and the money for malung th~sand a section of tiack aga~nstthe guldc ]ail To obv~ateone valiable, tlie l~ftplo- 1s now avarlable It totals something ovel 2 2 mllhon pounds duced by the shape of the body is puiposely spoilt by bleedrng A t~ack between Pal IS and 01leans 1s be~ngplanned and this all lnto the legloll of low pressule Cul~entlycushlon piessure w~llbe calrled over the count~ysrdeon pilla~sTh~s glveb the of alound 250 mm to 300 mm of wate~ ale employed It 1s nilnlmum ~~ite~feieuceon the giound and at the same t~meLhe thought that this offeis the best economlc compromise For h~ghest piotect~onagainst anlmals and stupid humans veloc~tiesup to 300 km/hl and pelhaps 400 km/hl (186 to 248 n~l/h~) Runn~ngon the present t~ackwhlch 1s suppolled on pillais I.[/@ nie indehrrd lo Herriiz & Cie fo~illu.rti'ntiorz Pigs 1, 2 onri 3 rrrqd lo The Hriri.slz Nydro~rrecltn~zicsRr,setirclz As,socicliio~z fov the fncilitir,~ at 6 n~ (19 7 ft) ~nteivals,the Aerotlaln has come aga~nstwhat oiforde(1 fro r~a. 41 british hovercraft corporation limited YEOVlL ENGLAND