00 UDAVID W. TAYLOR NiAVAL, SHIP CRESEARCH AND DEVFELOPMENT CENTER 0 tn

I Bethesda, Md. 20084

SEAICEEPT.NG EVALUATION OF THE JOINT ARMY/NAVY

BALLOON TRANS3PORT SYSTEM

by Ccz David M. Gertina

~~~~ ~~~APPROVED FOR PUBLIC UELEASE: ITIUIO NYIE

SHIP PERFORMACE DEPARUhEV

0

May 1976 SPD68O

MAJOR DTNSROC ORGANIZATIONAL COMPONENTS

COMMANDER

TECHNICAL DIRECTOR

OFCER-IN-CHARGE OFIE I-CAGCARDROCKANNAPOLIS

05 0

f SYST EMSIDEVELOPMENT

DEPARTMENT

r $HPPERORMACE IAVIATION ANDIP DERFOMANTCE SURFACE EFFECTS

DEATMN DEPARTMENT 1

. COMPUTATION...... T-CUE AND MATHEMATICS

DEPA RTMENT DEPARTMENT17

SHIPACOUTICSPROPULSION ANDSHIPACOTINS AUXILIARYV SYSTEMS

DEPAR MENTDEPARTMENT 27

MATEIALSCENTRALMATEIAL N. I NSTRUMENTATION

DEPARTMENT DE.PARTMENT2B /_____

.. zz

AA. N1

ql4

UNCLASSIFISDV ~~SECURITYr CLASSIF1CATION OF THIS PACE gfnion bale £tlsmo__________________

KPIN XLUATION OF THS JOXWARHP(/AVY

TWAISPORTA)S~

1.PIFWI ORGANIZATION NAME AND ADDRESS 0 a PROGRMLEMtN.RJ.T AtSh p r orance Department AIbWRK UNIT NUMSICI$David W. Taylor Nava) Ship R&D CenterBieathesda, Marylandl 20084 Ui

IL. CONTROL.LING OFFICE NAME AND ADDRE.SSaMobile Support System Group my0§David W. Taylor Naval Ship R&D Centert3 M9 OPAEAnnapolis, Maryland 2

14. MONITOItNG AGENCY NAME ADDRESS(## diUqt Em,, Ottt~ti1c.) It, SECURITY CL~ASS, (of this f00)

Unclassified

* APPROVED FOR PUBLIC RELASE. DISTRIBUJTION UNLIMITZED

Is.$UPEIMiNYANY NOYIK$

} Balloon, Traueport, Seakeeplzig, Vessel Kotiouo, Container Of floading

10. A"YRACT (CflhIto~ 44 rdAV**0 old#. It .,."W~ 40 I4.$UJ& br Wftk .Imv)

-Iiiurnsthe fivalukktion, of the joint Aray/tNavy Balloon Trawiport Systemconducted off of Green Beach, Ft.* Story, WVginia, the David W. Taylor N~avalShip Reear, h and Developzent Centor (DTNSRW)C vas tasked to mesure shipmotions on somie of the vessels used in the operation. The vessels instrwmonteby WNSWC were the Army's BM~ "LT. COYL. 3M-I V. D. PAGE," the LST 1180 '"tJSSK4NLTOWV~,g and two Navy W.AUa of the 1610 series (1658 snA 1659). Two prlaci-pal con~lguratione to remove Hilvan containers from thu vessels vere

WO W 43 es"Io'IOV~~OO~ya

ItCJMT~LAUziFCATIOS OF II PAGO ga9kV.1

UNCLASS!IEUD10-UITY CLASSIFICAMIN Of YI4S PAGE(Wha.e Date Mo.tored)

1nveatigated. The f irst was a ship to shore maneuver for which DTKSflDCinatrumented the BDL and the LCU 1659. The second was a ship to lightaroperation for which DTNSRDC recorded ship motion* on the LST 1180 Ad theLCUO 1658 and 1659. Throughout the operations, the motions of the vessel$Investigated were, In generalt rather small with the largest motionsoccurring aboard the LCUs when they vera fendered off of the larger DDLand LST with Yokohama pneumatic fenders.* The vessel motions were not thelimiting factor in the operation of the balloon transfer system. ObservatimIndicated that the ability to get the vessels into th.proper position andweather operational limi~ts of the balloon were of greater significance in

........... the successful transfer of Hilvan containers from the vessels.

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SaCURi~v CtLAW1P1C4%1104 Op y"Ih PaO((f. ii "a #A###"

A.I

TABLE OF CONTENTS

Page

ADMINISTRATIVE INqPOEMAIUN o.*.f t0f t~'f t~".f t

INTRODUCTION e ftf t fft'f t ',1

--7SSEL PARTICULARSo INSTRMIhFMATION AND DATA ANALYSIS . . ... . . . 2

BDL "LT. COL. JOHN U. D.PAGE" * f tff tfttfttfttft2

LST 1180 "USS MANITOWOC" .t . . t. ft ft . f .f . .f ft .ft . 3

LCU 1658 AND 1659 . ft . t . ft . . . . . ft ft ... . . . . 3

DATA REDUCTION TECHNIQUE ftf tf tf tf t-f tf tf t00f t 4

TRIAL CONFIGURATIONS . ft .t .t .tf tf tf tf tf f tf t*f tf 5

RESULTS AND DISCUSSION .ttff ft . t . t ft . t ft . t ft . t ft.*f f. 6

CONCLUDING REM4ARKS .tttfff ft ft.f*f tf tf tf tf tf 7'

LIST OF TABLES

Table 1 - Single Amiplitude Siguificant Voluea for the SDLand LOU 1659 iv., the Ship to Shore and Ship toLighter Corfigratio .f..f 4 . . . . . 8

Table 2 - Single Amplittudt Maximum Values for tiie BDLand LOU 1659 in the Ship to SIbove and Ship toLighter Configurations f0 tf f tf tff 9

Table 3 - Single Amplitude Signiificant values for theLST 1180 and 1ACUa 1658 aud 1659 in the Shipto Ligher oafigu ratto.. I . .. . . .t. . .. . .... 10

FTable 4 - Single Amplitude Haxiium Values for the LST 1180and LCUs 1658 aud 1659 in the Ship to Lighter

Configuration . . f t . . . . . . tf tf t tf t1

.ZL

Figue 1-Recosrted fo PR r Baloo 3,I 4 5 of th Balo Transporgeiue2 Shiptom Shluoan Sh1t5ihe Cniuain

Figure 4 Wave Height Spectra versus Wave Frequenicy asRecorded for Runs 2, 3, 4, 5 of the Balloon TransportSystem Evaluation . . . . . . . . . . . . . . . . . . . . . 5

Figure 6 Wave Height Spectra versus Wave Frequency asRecorded for Rune 6, 1, 8,t 9 of the BalloonrsptSyasotm em Evaluation .. . ........ 16

Figure 6 - Wave Height Spectra versus Wave Frequency an

Rec~orded for Runs 14, 15 of the Waloon TransportSyatem Evaluation~ , . . * .. * .. 18

iv

ABSTRACT

During the evaluation of the joint Army/Navy Balloon Transport System

conducted off of Green Beach, Vt. Story, Virginia, the David W. Taylor Naval

Ship Research and Development Center (DTNSRDC) was tasked to measure ship

motions on some of the vessels used in the operation. The vessels instrumented

by DTNSEDC were the Armys a DL 1LTQ COL. JOHN~ U. D. PAGE." the LST 1180 "USS

MANITOWOC," and two Navy LOUB of the 1610 series (1658 and 1659). Two princi-

pal configurations to remove Milvani contcine~s from-the vessels were investi-

gated. The first was a ship to Shore maneuver for which DTNSRDC instrumented

the BDL and the LCU 1659. The second was a ship to lighter operation for which

___ IDTNSRDC recorded ship motions on the LST 1180 and the LCUs 1658 and 1659.

Throughout the operatiLons, the motions of the vessels investigated were, in

-~general, rather small with the largest motions occurring aboard the LGUs when

they were fendered off of the larger BDL and LAST with Yokohama pneumtic

fenders. The vessel motions were not the limiting factor in the operation of

the balloon transfer system. Observations indicated that the ability to get

the vessels into the proper position and weather operational limits of the

balloon were of greater significauce in the successful transfer of HilvanW containere from the vessels,

ADMINISTRACIft INOMAION

This vork ws authorized by the N~aval Vcilities Xugineerin& Commaud

Work Request Wfl 09090 and identit-ed as Work VUit 1-1175-128.

ENV~ODc~O~

Invtatigations of the joint Army/N~avy Balloon Transport Systez were

conducted off ot Green Lucah, Vt, Story, Virginia, during the apriuR of 1076.

Ship to 3hOte and from ship to lighter by means of a helium filled ballooa.

n. l AThe primary balloon syc~tem, see Pigure 1, consists of a 500,000 cubic

foot helium filled balloon, two yarders (diesel powered level wind winches) and

a third winch, used in a manner similar to the yarders, for positioning the

balloon. The yarders are used to control the elevation and lateral positioning

0f the balloon in a plame bounded by the distance between the yarders and the

length of the cable on the yarder reels. The cable from the third winch is

attached to a block through which passes a cable from one of the yarders and,

with proper positioning of the !'Flying Dutchmaus" enables the balloon to be

moved transversely out of this plane.

Duiring the operations one or both yarders were aboard the LCUs, and the

winch of a warping tug, i.e., "ligDutchman," was used as the third point

of control in the positioning of the balloon, Ship motion measurements were

recorded by the Center on the LCUs which carried the yarders and aboard the

container carrying vessels, the BDL and LST.* Seakeeping data were collected

when the MIilvan containers were being on or off loaded from the vessels, The

results of this seakeepiog inormation are presented in graphical and tabular

form to aid in the overall evaluation of the feasibility of the balloon trans-

port system.

VE~SSEL PARTICUL=IN lSTRMWbTATIO4 AN~D DATA ANALYSIS

ML"LT. COL. JOOI U. D. PAGE"

The Army M is a 304.2..foot (92.72 toetra) landiug craft with a 65-foot

(19.81 %Letre) beam, 7.5-foot (2,29 metre) draft, and a disoplAcement of 2345

long tous (2383 tonnes). In the balloon transport system evaluation, tht BDL

was principally used as a container carrying vessal from which Milvau cou-

tatters were removed in the ship to short operation. Thriug these operations

the BflL was equipped with a Mark IV s table platform to measure the ship~ '

motious. The Mark TV stable platf~orm measures ship pitch, roll, and vith

j three stabilized axis accelerometers yields the vertical, transverse, a-ad

Niaval Ship Engineering Center, Norfolk. was responsible for twtion maasure-tumt abardthewarping tug ad Owe Iaveride-t buoy.

2

4 longitudinal accelerations at the point of installation, The installation

location of the ark IV aboard the UDL was 1.5 feet (.46 metres) to port of

centerline at amidships and two levels below the main deck, Thus acceler-ations measured at this point (near the ship's center of gravity) .;ould be

converted to displacements representing heavet sway and surge.

LST 1180 "USS MANITOWOC"

The LST 1180 is of the "Newport class" and has a full load displacement

of 8342 long tons (8476 tonnes), Its length overall is 522.3 feet (159.20

metres) with a beam of 69.5 feet (21.18 metres) and a draft of 15 feet (4.57

-" metres). The LST 1180 was used in the ship to lighter operation with the

LCU 1658 tied alongside. A MNSRDC strap down motion package was used aboard

j i!!:i ithe LOU 1658 with pwer for the cloctronic transducers comin from the enuip-

ment used aboard the LST. This power requirement limited the positioning of

the electronic equipment aboard the LST to an area where a cable run to the

LCU 1658 could be made. An area for the Mark IV stable platform location was

selected at Frame 235, 8.5 feet (2.59 metres).below the main deck and 12 feet

(3.66 metres) starboard of centerline in the PASSAGE AN) CONFLAGRAtION STATIONNo, 2 (2-235-11. This is a s"all compartmeut one level below the main deck,aft of the tank turntable and helicopter landing pad. The use of this location

did not permit heave, surge and sway measuremets o- the ship's center of

gravity, However; it did allow meAsuremente of the vertical, transverse &ad

lougitudinal accelerations of a point near the llflvau contaiuer off and on

lotding operations, and enabled the necessary cable run fot the LOU 1658.

LCU 1658 ND1659

S .. The LCU 1658 and 1659 are of the 1610 series with a length overall of

134.9 feet (41.12 metres), a bea of 29 feet (8.84 metres) aud a draft of

6.1 feet (1.86 metres), The LWl of the 1610 series have a light displacement

of 200 log tons (203.2 tonnes) and a full load displacemeat of 375 long tons

(381.0 tonnes).

Tlhe LCU 1659 wtm instrumented with a Humphrey stable platform which

is equipped with a vertically stabilited directiona gyroscope for pitch and

roll measurements and three axis accelerometers. During the first stages

3

of the operation these aceelarometerf. Ratiled and were replaced by a Donner

double integrating accelerometer for the heave displacement signal and two

hard mounted accelerometers for surge and sway acceleration signals. The

surge and away accelerometers wcre part of the DTNSRDC strap down package

which was later moved to the LCU 1658 for the ship to lighter operations.

The electronic transducers were positioned near the center of gravity of the

LCT 1659 6.8 feet (2.07 metres) below the main deck. 11 feet (3.35 metres)

aft of bulkhead 40 and on the centerline.

The LCU 1658 was instrumented with the DTN4SRDC strap down motion package

which consists of a Honeywell gyroscope to measure pitch and roll and three

hard mounted Donner accelerometers to measure vertical, transverse, and longi-

tudinal accelerations. Due to a limited length of transducer cable, the

location of the DTNSIU3C strap down package was dependent upon the location

along the length of the LST at which the LCU was tied. For Russ 11 through

14 the LCU 1658 was positioned A.loug the -port side of the LST with its Widshipa

centered on rame 184 of the LST iund the location of the strap down packageaboard the LCU was on the ceaterline of the main deck at rame 1$. For Rua 15the LCU 1658 was positioued along the starboard aide of the TOT again with

its midahIps centered about Frame 184 and thta strap dowan wotiou package was

relocAted on the ceaterlina of the maiu deck at Frame 55.

Throughout the duration of the operations the sea state was mea ured by

Mea of a Dfitawell 1Vamorider buoy provided by UAVSE, N~orfolk.I 13A.IUA REBUCT ION TEMWQQUEThe data signals were recorded on vioual direct writing oacillograph

uWits ad analog tape recordera during the luvestigatious. The ansag tapes

ver(- later digitized aud analyeced at the Center on an luterdata computer. The

calibrations were entered into the computer as tagineering units per volto

Sa a the data were digitized, prelimiuary analyses were perfomad to givethe mean ad root =ean square values for each chael.

Two comp~uter psasts were made on the data. During the first piase the

mean valua of the signal was computed along with rAxlmum and minimum values

from tlhe digitized tima domain data. During the second pass the teAu is

4

V subtracted on a point by point basis from the data, while a EAST FOURIER

TRANSFORM spectral analysis is performed on the data to yield the signifi-

cant values.

TRIAL CONIGURATIONS

In the evaluation of the balloon transport system there were two princi-

pal operational configurations, These were the ship to shore and the ship to

s!.lighter configurations. The ship to shore operation involved three vessels

as indicated in the upper half of )igure 2, i.e,, the BDL, the LCV 1659 andthe Warping Tug No. 34. In this operational mode, the B3Db was moored and

umsed as a container carryirg vessel. The LCU 1659 was tied to the starboard

side of the BDL and equipped with a yarder to serve as one point of control

for the balloon. The second yarder was on the beach and the warping tug'- ;(equipped with winch and block) served as a "Plying Dutchman." During the

ship to shore operations the LOU 1659 was tied to the starboard side of the7.1 BDL with its bow directed toward the WL'a stern. The LOU was positioued

forward of the lL'a midships aud feudered off of the HDL with two Yokohoa

fenderu. As seen in the upper half of Figure 2, tht principal direction of

the s.ell compouent of wave height during these operatious was off of the

BDL's starboard bow sad the L U's port stern. As iudcated, the apparent

j direction of the swell varied relative to vessels. This was due to the

shifting of mooring lines and chan g sn he vessels' position. The relative

positioning of the vessels involved in the operation is critical to the

proper maneuverabia.y of the balloon in trying to remove Kilvan containers.

In the Ship to lighter operations, both yarders awere aboard LCUs and

all three points of control were attached directly to the balloon tethering

liae as indicatel in the lower half of Figure 2 and in Figure 3. The first

attempt in the ship to lighter operation involved the 13DL, LOus 1656 and

1659 and the uarping tug. During this briaf attempt to move containers from

ship to lighter, the tooring of the BDL shifted and no containers were off

*loaded (Run No. 10). The remaining runs were conducted using the LST 1180,

LCUs 1658 and 1659, and the warping tug. As iudicated in Figure 3, the

* relative mooring configuration between the vessels changed; this was

principally the result of the change in current direction and an attempt to A

keep the LCU 1658 on the lee side of the LST. As seen for Runs 11 through 14,

the LCU was fendered off the port side of the LST with its bow directed toward

the LST stern. The midship position of the LCU 1658 was located about Frame

184 of the LST with the LCU 1659 seaward of the LST and the warping tug off

the LST's stern. The vessel configuration for Run lF ras similar to that for.the other ship to -ighter operations with the exceptLin of changing sides of

. -the LST and the wind driven waves being 180 degrees out from the swell.

RESULTS AND DISCUSSION

Presented in Table 1 are the single amplitude significant values for the

ship motion data recorded aboard the BDL ard LCU 1659 in the ship to shore

and ship to lighter configurations. In adeition to the single amplitude signifi-

cant values for each data channel. the d~ste, run number, tima of run and aigi-

.-icaut wave height, ( )1/3, are given. From this information the wavo spectra

measured during each run can be selected from Vigures 4 through 6. In those

instances where data were unobtainable due to tranaducer failure, electronic

malfuaction, technical difficultiei in oeneval. ete, the *ord "out" i used.

The (0) for Ruu No. 5 is to indicate that the data for the LOU 1659 was not

recorded simultaneously with that .f the bML. The time of day for Rad 5 on

the W vas from 1340 to 1405. The sea dtate condition during which fic +'

the vesel's data were being recorded for Run 5 was the 040*4 however, the

LCU 1659 was being repoaitioned (moved approxmatuely 30 feet farther forward

along the length of tha 9DL) while its motions were recorded.

In a similar format, Table 2 proaenta the single amplitude maximum values

recorded for the BDL and L U 1659. The umximum values for the displacement

siguals obtaiaed from double integration of acceleration signals are unobtain-

able, since the maximum values are obtalued from the time domain auglysis

and for these channels this would be in terms of g's, not fett.

Tablet 3 and 4 present the single amplitude significant and maxium values

recorded aboard the LST 1180 and LCJs 1658 and 1659 during the ship to lighter

." operations. The format used in presenting the data is the 6aze as for Tables

1. 1 6

1 and 2. The wave height spetra recorded for, each of. the runs are given inFigures 6 and 7.

A. indicated in Figures 4 through 7, the significant wave heights measured

were of the same magnitude for moet oi the runs in both operating conditions.

The spectra presented are point spectra and thus reflect the total wave energy A

regardless of direction. The swell component that existed off of Green Beach

was generally directed straight onto the shore and was the principal source

S-,of wave energy, as indicated in the various spectra as the modal period (period

of uaxmum enegy), with the windkgenerated waves having no noticaably differ-

, ient direction except as previously indicated tor Run No. 15. The direction of jthe principal swell component, as indicated in Figures 2 and 3, was derived

visually, and in many instances was difficult to determine due to the small

.F wave height and superimposed wind waves.

CONCLUDING REMARKS'I

As seen from the tables of single amplitude significant and the maximum

values presented, the motions of the vessels were, in general, relatively

small and did not inhibit the balloon transport operations. The largest motions

recorded were for roll on board the LCUs wheu they were fendered off the larger

vessels with Yokohama fenders. The motions of the LCUs were aggravated by the

stretch of the nylon lines and the resilience of the Yokohama pneumatic fenders.

Observations of the overall operation indicated that the ability to get

the vessels into the proper position and weather operational limita of the

* balloon are of greater significance in the su,'cessful transfer of Milvan con-

tainers than are the absolute motions of the vesse.ls involved. ..

7

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