Evaluation of the performance of human operators as a function of ship motion

198D

ARCHILF

AprU 196e

EVALUATION 0F THE PERFORMANCE OF

}MAN OPERATORS AS A FUNCTION OF SHIP MOTION An Engineering Psychology Sidy

Aboard the USS GLOVER (AGDE i)

By

F. Warhurst ad AJ. Cra sani

Ll,. vSSc1juwkunde

Technische Hogeschool

Dell t

ELECLAB 225/68 Report 2823

Roil stabilization should be

active from dead-in--water through flank speed since mission requirements include extensive operations at lor speeds.

ELECLAB225/68

ABSTrZACT

This study examines in an operational setting the hypothesis that human

performance

is significantly affected by ship's roll. Particular attention is paid to the nature

and effects of roll stabilization equipment The hypothesis is expanded to include the broad spectrum of human performance and the more subtle aspects of ship's motion.

iNoLaL)Le LJUd

Ei(_LUQe:

Ship mctior causes an irrelevant str2ss on crew members.

Some irrelevant stress may actu-ally be beneficiaL.

-OThe effect of

roll stabilization equipment.is diphasic; it reduces intolerable

roll am1itudes but tens to induce higher

linear accelerations.

i3TRA'nVE INFORMATION

This report covers a component of ihe work accomplished under Sub-project

S4627-020, Task 13694, that is being coordinated by NAVSEC (SEC 6165C4). _The work was done under Assignment A624-l5O.

ACKNOWLEDGMENTS

The help of Dr. G. Wendt and Dr. J. Cameron of the University of Rochester

for their insucn .n and permission for the use of the Adjecfive Checklist is

appreciated.

The officers and crew as well as civilian persormel and liaison officers aboard

the USS GLOVER (AGDE1) were especially insighul and cooperative. in support of this

experiment.

-.

= - -

-ELECLAB 225768 Iv

H

--TABLE OF CONTENTS ELECLB 225/68 y

Page

ACKNOWLED 2IENTS INTRODUCTION 2APPROACH --- -. LIMITAT IONS METHODS -RESULTS-

--

7

DISCUSSION AND CRITIQUE 10

CONCLUSIONS AND RECOMMENDATiONS 13

APPENDIX

AppendiA--Printe.Materia1stJse

in Critical

Incident and Motivational Data Collection

(5

pages)

DISTRIBUTION LIST

AL SHIP RESEARCH AND DEVELOPMENT LABORATORY

- EVALUATION OF THE PERFORMANCE OF

HUMAN OPERATORS AS A FUNCTION OF SHIP MOTION An Engineering Psychology Study

Aboard the USS GLOVER (AGDE 1) By

F. \Varhurst and A.J. Cerasani

INfl ODUC TION

It is well known that some vehicular motions cause individuals to become ill; the

symptoms are faintness, dizziness, sweating, sleepiness, and nausea. The medical

name for the condition so caused is 'kinetosis," but it is commonly called TTmotion -îckness" or tfseasickness.Tt The performance level of a sufferer of acute kinetosis is

understandably lowered; he may be unable to perform at all.

For purposes of this study, however, we are not concerned with the performance of subjects exhibiting suh symptoms. Our assumption is that, even though the subject

!n2L.î(* (as shown by observation and subjective report), his pformaucernay.be

altarey the fact that hissubject

to vehicular motions. It is obvious that the

motion of a ship degrades the performance of a man performing a task where mass, balance, ad accelerations are the key parameters (cariying a heavy weight, balanc-ing on a narrow platform, traversbalanc-ing a wet slippery deck), This investigation is

'i-ned at deteriuining the more subtle effects on performance resulting from

log-time exposure of the subject to such motion.

There are many equipment-design solutions to iñotion-induced difficulties aboard ship (handhoids, high-friction deck surfaces, raised edges on work-table surfaces). Ma.y of these solutions have been used aboard ships for thousands of years and many

others could and should be devised. However, these represent attempt.s only to cope

with motion in gross motor tasks and may have little or no effect on fine-motar and

cerebral tasks.

The use of whole-ship roll- and pitch-stabilization equipment promises to elim-inate undesirable motion effects through partial elimination or alteration of ship motion about two horizontal axes. We limit our concern here to roll-stabilization apparatus

such as thatfound on the TJSS GLOVER (AGDE 1).

LEiC

Boll-stabilization gear on the OJ.OVER consists of two darlike planes protudirig

at a_depressed angle irom the chine Tine, one oachid üFanTìdship EE1T

is powered by sçurs tied into the ship 's gyros.

The control inpuEi'

th

ars-r

dented with respect to the

water through which they are moving to provide dynamic forces whlimiLr.olliag;

the sys tedos notatt

;tte-Je?p th

p:vøtical,: :Hull-through-the-vater

speeds of less than about 12

ar!fi3ttcprod51e signiíToll-1imiting

moments bythreans. \Vithin the design prformance

l6p1 tA29 kibt5).

this equinent does reduce the maximum amplitude of the roll. However, its effect

is not merely that of partial elrmiaonit rather of altration also; momenry

lateral accelerations resulting from roll may actually be increased at points not on the roll axis of the ship. Alterations to other natural motions of the ship (pitch,

heave, yaw) are suspected but unconSlrned:

The- theoreticaHypQthest2-:to be-tested by-this irw.estigation is: Human

perform-anceissignificant1y

fc±edby:sJñproll.

-- r:

:BOACli

Anatm war- rnadeiintbis stdy-4ouse-all:th'ee -major methods of engineering

pb: -phenornenological qi'oserïation

corxela-tion of cause -and-effect related

events, and pure exoeriment involving thernanipulation of an independent variable and

therecording of the dependea variable. Furthermore, immediate performance

measures, bothqn2Trti-the and qualhttii, an&anjrfer.ential measure of performance

mot vationaLleveLwereused.

---Phenornenologic-al observation±requjres thegatherin, without manipulating the

envircnmentof- datain-the-fQrTrroIunquantified particulars. These data may be of events directly observed by the experimenter or may he reported to him by individuals

in a position to ke recobservaion:The-iiiained experimenter (E) practices a gross criminatioainchoosing what.isTrecord and what is not; for example, he does-not record thannomalistic behavior, of a subject (S).if S is influenced by a stimulus o'oviousi7 unrelatedto the one-in question. On the other hand, all departures from the

norrt; in the.ab-sence o usejudgedinrelated .tqtbe cause in question, must be recorded. The events within themselves may contain qualitative measures such as

ITeasy, difficult, very difficult" when referring for instance to how a certain oh ws

afecthdbyship motion

enie-daa

y

tatered and results are tabulated,

certain fronds-may be- seenvhich are notappa ntJrm cursory observation. Just

as.importnnt, certain trends which, seem to be apparent from cursory observation may

be-dispe]JecL LmportanLconcIusions may be. drawn from the relave absence of

ab--noiiiial events in the presence of the variable in question.

the method of correlation to test a hypothesis, quantitative data

con-ingetswhicharjdedthbe;based on pilot analysis,

a function of the

vari-Jtis,ofcourse, lntrmnsicallyimportant\vith this method

--TEaLthe ar

iquesdos-j-fact vary and that other unspecified viriaoles

-whih-rnay-fectThe-data-rerrìain smalor randomize out. _{It is entirely possible that}

by noise. Since the problem of human

perfoa.anc-e aafnGtiop

p- motion is complicated, the use of the correlational

of subjects and trials in order to assure

adomizatianof uiicónrolledrjab1es. The data

so collected are tabulated and values which imply a causal

rela-oibetweea

s-sjip motion and human performance.

- -The experinentalmethodjs the most precise and provides, therefore, the basis

---for making-the most valid conclusions in tesng the experimental hypothesis. _It involves manipulation of the independent variable (ship roll in this case) by the

ex-- perimentex' according- to a schedule designed to control or eliminate the effects of

un-wanted ariab1es.-xLthepresent case, examples of unun-wanted variables are: length of time at sea, time of day, practice effects in repetitive tasks, order of _presentation o(several tasks, length of exposure to any particular intensity of roll, time of test

within S's work period. This methodequires considerable control _{over the}

environ-ment and the subjects.

-T -ThII-TA-TIONS

-- The theory underWing a consideration of this problem must suit the real-orid

--circumstances. In particular, the theoretical hypothesis stated in the introduction must be made less general in three respects.

-First, the USS GLOVER, aboard which tins investigation _{as conducted, is rot}

:the "universal ship." It might be-called typical, but such vessels

as LST1s, * which

are even longer, are said to roll, pound, slam, and heave more than it does. Second,

:1mmetht observations were possible only of personnel exposed to the ship 's motion

for a single 2-week cruise. However, it is evident that a more stringent_requirement

- o_ .D O cia ,'

of vioe- r'oon ,ould be more realistic for re inesgatioì-

_{o this}

-_ qn While this

oìdiuon nay b rarely met, the high rehabiiicylernandedby

the system o _{hichtaQswarships are a part requires design for this contingency.}

-Third, circumstances of the cruise dictated agdnst pure eámiiiàtioiì f iàll versus .--no-roU.- -Consequently, the qieson involves rollversus roll with roll stabilization, ---each with respect- 0:human-PerfOrmance levels under no-roll conditions.

- *L,sT - Lending Ship, ank

ELECLAB 225/68

METHODS'

Throughout the cruise, the experimental team collected phenomenologicaldata

by personal oral and written interview and data on motivational levels by the

question-flaire method. After the initial orientation, three particular repetitive tasks were

chosen from 'which to collect quantitative data on a "whenever-possible

basis. The

recording of roll at times when immediate data were being recorded was handled by

the Shipboard Instrumentation Center personnel augmented by direct observation of

the clirioineter at other notable times.

Phencmenologieal data were gathered and recorded by the experimental team almost continuously.. The team toured all spaces of the ship from keel to topmast

looking for procedures and equipment configurations and arrangements designed to facilitate work in a moving environment. Areasnot routinely frequented werd visited often in order to accustom the crew to the team's presence and thus reduce the arti-ficial behavior which sometimes results from the presence of an

observer. These

,data were later distilled and organized, and summaries appear in the Results section.

The Critical Incident and Adjective Checklist questionnaire, together with an infoi uìation sheet and vocabulary list, comprise Appendix A. They were handed out as a package to each subject early in the cruise and supplemented by oral instructions. Copies of the questionnaire, alone, vere passed out and collected many times during

the cruises The particular areas and particular times selected were the galley, bridge, combat information center (CIC), sonar control space, boiler room, engine room, and executive office, usuallyat the end of watch periods. Roll was recorded on each occasion and later matched willi responses during data reductIon.

The Critical Incident section is self-explanatory. The Adjective Checklist

measure of mood was developed by Dr. G.. Wendt of the Universi of Rochester and

has proved highly reliable in measuring mood as a function of various stimuli.

For the experimental method, three particular repetitive tasks which were

chosen to evaluate human performance were the boiler feedwater analysis task, the

tping task, and the plotting task. These tasks were observed and evaluated during

various watch periods and, if possible, performed by different individuals. Table

i

shows these variables.

Table i

Tasks Evaluated for Human Performance

ELECLAE 225/C8 4

r-Number of Subjects

[ Number of Trials

Boiler Feedwater Typing Plotting

1

11 lo

Boiler Feed Water-Analysis Task

a. Purpose and Procedure for this Task. The GLOVER is powered

bÑì5i

iradst Tofls

va _{rhètitthe s team,}

o _{sma1l:lossis made up l)y}

:isiU-ation f:se

ato-d- adedto-the

of-tfre-sys te-m.- Because of

-r-the

? et fstry:ofth ste

_{esrin ticystern water.}

ef--the mecLhanieal:parts in the-system as a

function- of-cor±-centration and- i4 L'Theref&reany such systm miisE b tested

in this case, and "doused" (corrective chemicals added) if necessary to restore the desired chemical balance.

Each morning a boiler tethnician petty officer (BTPO) draws

Trni1sothe feeds tr

Th fiistample is-drawn from the main active system in

such a va3/ that its temperature can be controlled The sample bottle is removed to a

chemical analysis bench. A portion is filtered. Subportions are used to determine

and hloride levels. These tasks involve the use of specialized

:ale adu

,th iroductibti by the drop-countüig

or graduated burette methods

-- of color indicators, aid coÏor-matching with standard solutions.

-- _-- Sources of error include contamination of the sample because

- _{oLcarele-ss--procedures- -misjudging of-the miniscus, miscounting the drops,}

mis-reading the g-raduate, and mismatching-of colors _{Roll contributes--directly to error}

through the physical difficulty of "clean" pouring while rolling and through change in

-. the position of the miniscus with'respect to the graduations being read.

-b. Feewater Task Evaluation Procedures.

T: - - - - _- ---(1) The individual subject available for this test was a BT3ç

He was instructed to proceed normally being careful only to avoid interruptions from other persons during the task. - - -

--- _{(2) Atime rneasuie wes made of each subtash (four}

in-clüding cIañ-u ame).

-

-- :r

- 3) - A ualityf -work (accuracy) measure was made by

having a more experienced man run the same samples at a later time.

- - - - (4) The roll of the ship was recorded.

-:-- -- 2. Trping Task

a. Purpose and Procedure of this Task. A great deal of typing

is done aboard a naval vessel both inthe Radio Cmmunicalions Center and in the Ship-Office. A typing task involves manipulation and eye-tracking, both of which are

an unsteady environment. This Task is representative of the innumerable dataJogging2nd communique tasks that _{occur during} every ship mission.

- A master test page was constructed consisting of a 15 X 15

matrix of capitalized three-letter "Q" signals (e.g., QKZ, QJT, QMF, etc) obtained

----4ro _{-the--ship &-eemunicaons--Liudbtyt±--and iading-atthetop}

MAKE IDENTICAL COPY---NO CORRECTIONS NO TABS

-

LIIME

- CODE NAME:

-

---

-- b,

-TypiTas1E.vaIuation-Procedures.

_;

-

(1jL

three yeomen assigned to the Ship's Office. -

_:{2}ìaskswere administered daily under fairly vieil

Jedi$e-permitted on a noninterference basis. oil as recorded.

P1ot±in Task -.

-- -a.. Purpose and Pocedur? for this Task. Routine operation of the

GLOVER requirs the bridge to be well aware at all times of other surface vessels in her vicinity in-orderto ayoi collision. This requirement is met by visual scanning

of the sea surface by observation- of the surface radar screen on the bridge, and by more detailed information supplied orally to the bridge by CIC personnel. A dC

radar screen observer detects trets, determines

their range and relative bearing, assignsidehtificahon alid transfers fis informattoa. orally to a plotter. The plotter,

worirvith a inadrekoning table (DRT), plots the information with pencil and paper

ogethwithship's own course (SOC) and thus generates a true path which can be

read with the PMPR (drafting machine and scales) to determine target true course, speed, and closest pointßf approac (CPA). This information is then communicated

to the bridge orally on demand. A two-man team may handle in excess of 20 targets

simultaneously (each delineated by points numbering from 2 to N), upgrading and

re-fining the determinations, noting change of course and speed of the target or own ship or both iitimesôhanging paper or the location of the zero point in order to keep

their plot within the range of the ,D:ftTand sçratcbing targets of no further interest. Since-the:timeliness and acduracy of this task is vital to ship safety, this procedure

(sometimes complicated further by air and subsurface targets) can be highly stressful. Since it involves transmission of data orally scale-reading for input and outhut, low light-level conditions, a fairly high noise level and "distracting" environment,

vigi-lance and short-term memory, it isa good measure of human performance levels.

b. Test materials, Subjects, Evaluation Procedures.

A .T3 AN/SPS Trainer/Radar Target Simulator was pro-gram.med to presenton-the appropriate scope face six targets within practicable range

for the DRT at various bearings and at various realistic surface speeds.

Siibjects were six experienced enlisted men ¿perating

in teäñis bf tfo according to their vai1ahility. The CXC room proved to be a well

stabillzèd environment when it was available (usually during the 0000-0600 period).

Despite the fact that the test .rquired the presence of an extra man who would

ordi-narilb-sleeping, the- subjeets seemed well motivated, interested in their work, and

cooperative-.: Initially there-wasa great deal of difficulty with the erratic behavior of the T3, but it later gave consistent performance.

(3) The data were thken according to the realistic procedure

-utlind in 3.a. above, beginning with the announcement of a target by the scope

ob--server and ending with the announcement of a course and speed by the plotter. The

;targts were handled one at a time, and the SOC varied between trials to vary the task particulars. A time measure (in seconds) andan accuracy measure (in degrees and 1ots) are the performance measures. Certain gross errors are also observable on

the plotting sheets but are not subject to statistical analysis.

RESULTS

The results of the motivational and critical incident questionnaires are

summa-rized in Figure 1. MOTIVATION INDEX DENTS I I I 0 2 4 6 8 12

4

AVERAGE ROLL FROM VERTICAL _{DURING EACH 4-HOUR}

WATCH PERiOD, decrees

Figure i

Roll-Caused Incidents and Motivation Index as a Function of Ship's Roll - - _{- Obviously there are too few points to justify, mathematically, the curve which has}

- been drawn in; the graph is intended merely as a presentation device and will _be

discussed in the next section. lhe sort of incident being counted includes falls,

ELECLAB 225/68 7

6

4

stumbling, mistakes in judgment, spilling or dropping of materials, difficulty in handling tools which resulted in damage or injury, and mechanical mishaps which resulted from failure to anticipate the effects of roll on the movement of equipment. The motivational measure is based ou an arbitrary caie developed during research

in other areas,

The three quantitative performance test results were such that no valid mathe-matical freathent was possible. The reasons for this appear in the Discussion and Critique section. A number of useful observations were made possible by the test

situations, however, and appear with the other observations in this section.

The results of phenomerionological observation and interview anpear below. Not all incidents are reported since they are too numerous and redundant. Qualitative

phrases are used to indicate relative importance and frequency. The incidents listed are severely restricted to those which are obviously related to ship roll. Those

observations generally of interest to the engineering psychologist team will aDpear

a technical note (to be published) and indicate how&her specific items on snipboard onLributa to altered human pformance capabJities irrespective of ship motion

The resultant findings, summarized in Table 2, are as follows:

Companionway lights jut out from the bulkheads at frequent intervals.

They are so placed and configured that they are struck by the legs of persons negoti-. atng the passageway, expecially during heavy roll conditions. These were often located close to doorways, resulting in an aggrasration of the already existing traffic problem at these points.

° One of the suhiasks performed during the water analysis task required the operator to stand on a small stool. His position was precarious and resulted in

several minor falls during the trials.

O No preference was expressed by typists for orientation of their mar-.

chines with respect to the roil axis.

Seated radar operators, located high in the ship, preferred chairs with arms to those without.

Complaints were heard regarding the lack of restraint devices or. the

'new" bunks Which could not be loosened to prevent rolling out under heavy roil conditions.

r

EÏP.CLAB 225/68 8

O Radar operators vere usually rotated to other jobs every hour under.

low, and every 1/2 hour under high, roll conditions (high = greater than 100).

Personal danger to deck personnel increased greatly as a function of

t

roll and proximity to the sea surface.

O _{During heavy roIl, many deck surfaces on the weather decks and}

flSfdetduQt.O ftaCking

_{.thr.oh400z'sncLdue to. spillage- of various}

- -

fluids. Som oL,ese. surfaces

are noskidprofe

_{dpfer v.erypor. footing.}

Thhéhit

htedflìt

_{±ilF cfncaused}

Lz

ti _{-f x&and -icu}

di

_{arpgc- f:thc lathe}

:bd_feif and consequent inaccurate and

_{sometimes dangerous operation of the bol.}

Sleep distiirhnce was pf eareportedas _{an important negative, result}

IL _{hé jolt' th}

_{6e'etie fdrces}

_{f th}

roll

tabiliza-ition- gea

_{¡as-espeeiaily-disrup-the in-sces- rgmóved from-the roll axis.}

Both fine and gross motor tasks were made more difficult under any roll ¿ondition bitwere virb-ially shut down above a 15° roll. _{This was specially}

truof electronic or electrical

_{maintenance because of the shock danger and the size}

and configuration of the parts.

- --- -

- S

Such ecessary ship serices

_{as the galley and the laundry restricted}

-- Itheir operation at a 10° -roll and secure operation-if possible at 15°. _{Galley fires}

_:havc been.starte4hy-greae spilled by rolling;

- -

-_Vjsu.al contact, expecially by binoculars, was more difficult to

main-tain as roll increased.

- ° Certain pumps tnded to lose prime under heavy roll conditions.. This increased the need for vigilance by thepump tender.

!.ßpecial procedures and devices were necessary at designated work spaces when such small tools as pencils and screwdrivers

_{were in use. At}

nondeig-nated places such objects frequently must be retrieved after rolling away.

Sobe electronic test gages were sensitive te very low accelerations

on the. insuentcas such as would be caused by ship

_motion.

- OUnftue soundings resulted from fluid motion.ia storage tanks.

" In general, "one hand for the ship and one hand for self ' was the rule.

- Inaccuracies in placing plotting points and fri _{scribing lines through}

- peints were seen to result from roll motion and from the jolt resulting from the

righting forces of the stahilizaon _gear.

- _{ø The effects of roll coupled withimproper panel and control design}

caused inadvertent operation of a start/push but!Ion on a sonar control console. _This resulted in destruction of $75. 00 worth of fuses _{in a particular case.}

Roll onditton Degrees o About 4 4-10 Above 10 Table2

Summarized Findings of Equipment and Personnel Consideratioìs Resulting From Roll

Locomotion and Material Transport Normal Near normai Handholds Traffic Impaired Special deck surfaces Additionai personnel Additional thne Diffiu1t to im-possible depending ori weight, delicacy

of load, condition

of work space, &

feasibility of using

additional manpower

ELECLAB 225/fiS io

Personnel Behavior or Performance Areas

Fine Motor Tasks

Normal Near normal Extra care Steadying devices Tool holders Drawer stops

Raised table edges

Equipment restraints Additional time Additional personnel Extreme care fo avoid injury or damage

Gross Motor Tasks Normal Near normal depending on weight & delicacy of equipment Additional personnel Additional care Additional time Restraining devices Extreme care ta

avoid damage and injury

DISCUSSION AND CRITIQUE

A discussion of the results of this study must.be based almost entirely on the

phenomenonological observations made and interpreted through the expertise of the experimental team and consultation with specialists in psychomotor and psychological.

behavior of personnel in the environment of vehicular motion. Several factors pre-vented the gathering of statistically valid quantitative data. Because the

investiga-on was cinvestiga-ondüeted investiga-on a strict ninvestiga-oninterference basis, observatiinvestiga-ons were passive.

The number of personnel made available and the times and conditions under which

they could be used was limited. But most important, the independent variable in question, roll, was essentially of low value and constant throughout the cruise with the exception of a single 4-hour period. (Said one crewman "This was the calmest

tr1 we!ve ever had. ?T) Thus, the conditions necessary for pure or even

correla-ional experiments were r.ot met. While the GLOVER's roll stabilization gear cari

Motivational and Mood Level of Personnel Normal

Possibly elevated

Some fatigue over long periods

Lewered morale

tiredness, frustration,

and fear as result of

less sleep, greater

physical effort, & consequences of mistokes

AnrlIör1rrriotrsly-comprorntsesa1l shipboardwor

ir oh

themiènèntöfinen aad materials, at 20°ntuallval1noessential ship's

or

c _{- ultie-aTe-eon unel-with-Dersonne1- hazards-theweight of}

unsecured objects, thUelicacy of motionfrequired, slippery footing, narrow passages , and other aspects which tend to marke shipboard work only marginally

ossible under calmer nonroll conditions.

There is no doubt that a strong argtirneat can be.made for the cost

effective-ness of roll-stabilizaon equipment for _{jpswher roll of greater than 100 is} common. For those whose roll never exceeds 10°, however, particularization

de-.peing çmisio ìvouldçonfrol the argument.

- In the area of mdlium roll, 4to..1Q° ,there are two major categories of

humanperformance factors to consider. The first is the purely mechanical factor How does roll affect a man's ability to perform fine and _{gross motor tasks? The} second is more _{hologicab Does roll degrade his sensory and perceptual} cap-abilities directly or does hi physiological state lower his motivational level thus.

causing degraded perfoLniance?

The mechanical factor is obviously on a continuum. As roil increases so

does the difficulty of performing every motor task from walking down a passageway,

- to doing a delicate-soldering task, to lifting a heavy piece of equipment, to keeping

one's body in a bunk. Any examination of the costeffecivenessof _equipment

designed to reduce roll.would have to consider what the nature of the prime mission

and necssary supporting rnissionsof a vessel would be. Itisworth noting that

-ozThetasksm6ïvereÏy affected byroll aboard the

GLG/ER, eJectrornc

troubleshooting and maintenance, is increasing in importance aboard _{United States}

naval shic. Even old ships are being retrofitted with electronic _{devices which in}

many cases had no counterpart aboard these vessels before. The shock hazard, -smallness of parts, and susceptibility to destruction by inadvertent _{slippage of} - probes during a troubleshooting procedure when the ship is rolling become critical

In the newer circuILLy due to the complexity, sensitivity, high cost, and high-4evel

-

.-jj

of this equipment. --.-

-The mechanical factor also enters into the.future manning requiiremerits.of

naval ships. Many motor tasks require eitber

_{more time or more nanpoweror}

bothçause of rolj, Even under roll conditions

as low as 40 there is ample

evIdence that motar behavior is altered; _{men walking through a door under zero} roll (0' to 4°) do so "hands off" while at moderate roll, they find a steadying hand

neoessary. Fine soldering tasks. in moderateroll require extra aids, extra_time,

and a steadier work stance (gained by leaning the trunk against the workbench

ELECL.AB 225/68

ii

be controlled manually in order to induce roll, and was in fact manipulated for

approximately 30 minutc th procedure proved sopunishing to the stabilization.

chan

rimarfPstperSoaeeL-andproceCeSOR board that ft could not

bereeate.d, Furtherne,durirg:this Ttrip, the shipboard roll insfrumentation

or reje-Joals- and the

fllight-

Strictly iriteinmsof the me ha'ìcal factor,

the rolIöí-a-ship ma

reqtrmbie e-rs6nnel

Peduction of the o

roll ilcf all

iaóoIejòbth2X-IEéeht-must be halted and the

equip-ment lashed down. Ituld hardly affect others that now require intermittent stoppage

while the eqtipthentis rnereT eid

lTori-thë-case of tool-simplydropped

intb thfl'

tnêr

:

eeïè-it Ì

ärtii

iBeuits eetiñdepict an inefficient

work1ìre o1y-b4ufeenee ;.-n

e ep separture- from -the nozrn but

tells

ë-yliftle abut'bat-that-no-rrn

is.---Tbë secoñdagoryof-iman-performance factors to consider in the area of

medium roll is the nonmotor one the psycho-physical. and psychological category.

--One aspect-of thed ä,thérnötivati6na1T level versus roll, suggests that a slight

arnoutf roll is actually beneficia1 WhìIe these data cannot support this idea

mathe-matióafly thèreisa-raüonale te sipprt it.

flo11 constitutes what might be called

"irrelevant stresstT; it is a stimulus calling for a response which is at best irrelevant to the sb.mulus-response pcthre in hich-òne s interested

There is aleelof

ir-felevant stresgreater than zero vhích actually facilitates human response to the relevän1stimulüs. Roll at a-levél of aböit 3°To 4 may be this optimal level

How-ever ,bécause öf the

ultiplieIt-of othéi fÑelè äfstresses abcard ship (n6ise,

wind,-vihrafion-, improper lighting)a th fact that such motioi is very rarely at the

zero level, it remains an interesting but academic consideration; no whole-ship roll-stabilization equipment could completely cancel roll.

-Aove-tptitha1 r&l evelfaigii&i-probab1y the principal element in

psycho-logical impairment The literature 1,2 intheates that roll-stress, combined ith the

many other stresses and stinulì thê-bdy, results in sensbry and perceptual

im-parmt;eye fods-and f±acldñg, for instane is impairEd.

it i beyond the scope

of tb

eort thdathie iliiüthly thmchañiiñs iñvolved but, in pedestriai terms,

simple physiological faUgueestexplains what happens. All the consequences of sleep

deprition (which can be-

etrsult of-óll)

d excèsiíëly long workperiods

ar&simìiar to the consequences ofexposuretoTmotìon, the performance decrement beinga-function of time and intnsity. Itis The opinion of the experimental team,

based on observafls and-benultatio-with experEs in the field of mötion studies, that

the time and intensity of motion abbaid the GLOVER were insufficient to induce the

fatigue levels as a separate significant 'ràriablé in the investigation. In the real world,

may continue for 4 to 30 days, with consequent

buildup of fatigue levels.

-ELECLAB 225/68 .12

1Fitts, P M., and M. I. Postier, :'Hurnan Performance, Chapter 3, Belmont, Calif,,

Brooi-s/Cole Publishing Co ,

1967

-N. M., R. M, Chaibers, andE.

ed1,Thnusual Envlonment irn Hun in

Behavior,-Chapter.2, London, England,.FreeiPress £ollier-MeMilltan, Ltd., 1963

-/

other meanügfu1 diffrcrice between zéro and moderate roll resulted from this Investigation. The roll between 0° and 4° is practically sinusoidal and therefore predictable

But within tneeratiìalenvJopE. pf roll -sabiL z atiori equipjery

definite depart ea freni sinusidal motion can be felt; Jiese departures are often so

ong that they are best described as jolts

' A number of psvchiotor jnîs

directly observed were caus6d bythejpIts. Obviously these abrupt lateral

cclera--tions were more intense in areas of the ship such as the instrumenttion room which are far removed from the roll axis, although the frequency of occurrence is the same everywhere. The psychological results can only be inferred, but again, there ìs reason to believe that the effects ofjpiLgQfarbeyond the motor impairment level because of the unpredictability of their timing and intensity. As with noise, continuous

1evelnoxious stimuli are better tolerated than sporadic stimuli.

Roll is stressful to all shipboard personnel. An unpredictably changing environ-ment, especially while performing a task only marginally within the motor capabilities of the performer, constitutes stress, even high stress, depending upon the conse-quences. Stress is currently one of the most difficult problems in the engineering

psychology field. _{In the case of shipboard roll, it may prove to be the most cons}

equen-tial variable of them all, but because it is so nebulous, it is the most difficult variable

to quantify.

CONCLUSIONS AND RECOMMENDATIONS

The hypothesis to be tested, that human performance is significantly affected by

roll, is clearly supported by this investigation. .1any motor incidents are clearly

caused by roll motion. But while this may 'oc evident to the casual observer, t more subtle results of the investigation may not be. They are:

-O Lateral accelerations caused by roll-reducing devicesmgy be more harmful to human performance than some greater amount of roll,

A small amount of roll may be beneficial.

The true effects of roll are buried in a sea o other ship-soecific,

antstim4ncluding noìse, vibration, climates char

daF les, and the

nanning and Urne norms established for any task.

O There are three distinct regions of human performance along the roll continuum. These regions are 0° to 40 4 to approdmately 10°, and above iö

They correspond to ranges at which men can work at various efficiencies, as depicted In Figure 2.

' The effects oo'

_aIflI

said to he simply additive:

An Intensity of roll which causes a buildup of fatigue may allow

unimpaired performance for a given Urne after which performance may be sharply -degraded by au. "energy deficit."

Roll as an Irrelevant stimulus, added to other irrelevant stinul1 thich as poor illumination, may cause disproportionate drop in perfbrmance with relevant stimuli such as perception of anobject to be tracked.

The effects vary. according to what part of the continuum Is being

examined. The ratio of 60 to 3° is not as 30° is to 15°.

' The irrelevant stress of ship roll in the moderate to severe range

cannot be treated in the same way that some other human perforiìiance factors, such

as arm length, are treated. Itt are not subject to a

high degree of

quanüfica-tian,

Instead it is more realistically categorized with noise, humidittne,

vibration, and other causal factors which are best treated by broader, more

qu1ita-tive means.

o.elow the levels which cause overt nausea, the psychological effects of shi? motion may be measurable niy through such intermediate forms as motivation level and incidence of somatic illness. I.e., if a subject is unable to perform because

of i. cold or headache, that somatic ailment could be the psychogenic effect of the

variable in question ship roll.

SUghty E)evctd

No r mcl

S)ep Nrmo)

>.e'Som Faflgue

lLJ Some Increase ¡n Effort

cJw A S!eep Dfficu}t Increased RztTrue w Addiionc! Mcnpcwer Reqted

o

(I) )_JStrerTJous Effort Required

_Norrnal Eating DirfuiJt

Nocmc1 S1eep LrnpossbTe

MaJmurn Fatigue

Tota) Incapacitation

ELECLAB 225/68 14

_I

₄₀₀

O 4° lO 200 300

AVERAGE ROLLANGLE FROM THE VERTICAL FOR PHOLONGED

PERIODS) degrees

Figure 2

i:he principal rccommcndation which results from this invcstigition involves the nature of the

stab-ilizatioD_cqu pmitIty.shou1d

be

öportTi cdrn 'tc

espec aiiytn-moETi

pectinì- Strict

frthc motar performi.ncepomt of view, a tiade-off function

shouid_hegcnaLcci throughout the_roll spect um between the deleterious effects of

higher apiitu.cji1oU rdu

cqrati5nsnecessar to aeClucè that 1611

-Sine duringthese

peri---ods on th oc-en sea- they broach-to and waUocoxsiderablas thercs.i.dt oL swell actioL

-1deaflo11 stabuxzatons1ìoui&beeffectweìnthis conditioir --- -

-:-

-- _- Also :.itis :r.ecommended that bilJztiçquipment be installed on any ship

wiqjs. expected to roll above 10° and on which on-going motor tasks

recritical.

We are currently conducting another investigation to detexinihethe decrement in huma

perfoiivance in the postmotion period; it is riot clear that normal performance ruirc

ments can be met.by personncl iimnediately after bijig exposed to iolent motion

Further investigâtionjs recQmmended. Howver,it should be empas{zed that

any investigation aimed atdeteiinIng the effects of ship roll on human performance must be extensive and must include equal consideration of the other irrelevant stresse.. with which roll interacts in the shipboard environment.

ELECLAB 225/68

__-..--_-. ---a.--- =- .---.-' _

-Appendix À

Printed MaterialsUsed iñ

ScIentific Study of loll

We ar. evaluating the possibility of Incorporating stabilization gear on a ship very much like your own, which has a certain roll rate. \Ve think that perhaps people

who are unaccustomed to the violent motion of the sea will form a part of the crew and we are interested in determining what effects certain kinds of motions, caused by the changing sea sttes, will have on their performance. We would like to have your help. Because of your experience and the fact that you are assigned to this ship, we consider that-you are in the best position to Iaow about these kinds of things and we would appreciate your cooperation on-hw:these conditions affect your performance. In order to simplify the task we would like you to pay special attention to your own

performance during thstlnte youare-onwatch; at-your jobs, relaxing, or eating - and

tell us how what you are doing was. changed by the motion of the ship; for example, if

you were sifting down at a desk or table writing and the motion of the ship caused you to break the pencil tip or if you were fixing something and the ship's motion caused

you to stop or slowed you down because you Imew if you continued doing what you were

doing, the ships motion would cause you to make a mistake. Please remember appro

imately what time this happened and how this happening made you feel. Also, tell us when the shipts motion actually caused you to make a mistake, what you were doing, and what the mistake was. To make this a simple procedure, we will provide you wi. a sheet of paper on which you can tell us about these happenings. You will use a code name of your own choosing and eery bit of information will be kept strictly

confiden-tia]. and used onJy for scientific purposes by us.

We thank you for your attention and ask that you feel free to ask us questions at any time.

apprehensive assertive 12. belligerent 16. brooding cautious changeable 24. _{close-mouthed} defiant depressed 33, detached 28. doubthil 4.3. _dubious 51. emotional -J'). _{engross ed} 6i,. genial hostile humorous 71, _{indiffe rent} 79' _{lackadaisical} 80. Lngiiid 85. _masterful 83. mischievous 87. _nauseated 89. nonchalant 91. _optimistic 93. remorseful

9. resourceful

14, suspicious 30. with dmivn LECLAB 225/68

Dictionary of Adjective Check _{List (ACL) Meaning}

The ACL is designed to sample your present moods, emotions and

motiva-tiens. For this reason

_{we cannot use any meaning in dictionaries, but only those}

applying to moods, emotions and motivations as they may now be present in you.

In the case of each adjective, you check it if your answer is "yes" to the phrase, 9 now feel active," "1 now feel keyed-up," "I now feel drowsy," _etc.

Several of the adjectives have_{more than one mood or emotional meaning.} Please use only the meaning_{we sDecffy below.}

Only in rare cases are the definitions listed below exact synonyms. They are meant only as guides to the _{approximate meaning. Only those words are}

de-fined which might often _{cause trouble. If you are in doubt about other}

words, please

ask one of us.

-uneasy or fearful about something that _{may happen}

inclined to eress and

_{press your ideas}

tendency to be quarrelsome, to _{disagree aggressively} pessimistically preoccupied

wary

likely to go from one mood Lo another; emotionally

variable

uncommunicative, don't feel like talking

a chip on the shoulder, aggressive _{or cocky opposition} blue, dejected

aloof, apart from events, _{not persopally involved}

unsure, uncertain

skeptical, slightly suspicious

easily aroused to emotion, having _{a high level of}

emotions

absorbed, involved in present activities or concerns relaxed, cheerful and happy

antagonistic, unfriendly

wifty

emotionally unmoved by events without ener or ambition

listlessly relaxed

powerful, able to control prankish or teasing sick at the stomach

casually unconcerned

looking on the bright side of things

feeling sorry about one or more of ones actions

ingenious and capable of meeting problems

distrustful

retracted into oneself, unsociable

List alFof the things you were doing that were affected or changed by the motion of

hship

Describe what happened in each case:

Describe where on the ship each of these things happened:

Check one:

During these happenings, the motion of the ship:

caused me to work extra hard to do what was otherwie no LivaI did not affect my performance in any way

caused me to slow down what I was doing

caused me to make simple mistakes caused me to be more cautious

ELECLAB 225/68 S A-3

Code Name Date

Do you usually expect to perform betteJes welL

same

as an average person?

This following list gives you a chance to compare how you feel now with how you felt

durLg the time that the ship's motion bothered your performance. Please go through

the list and show whether you felt more that way during the time you were bothered,

or feel more that way now Please answer every item.

ELECLAI3 225/68 A-4

)

The ship's motion during this last period can best be described by:

_violent motion

- - Specify which: - heavy

pitch-heavy roll

heavy heave

_cahn motion

jerky motion (unable to get ready for motion)

Have-yotr taken any drugs or medications of-any kind-iirthe past-perio&? Yes No . If yes, were they

Sedative or tranquilizer

Analgesic (aspirin) ...-- - - -Anti-motion sic1ess reedy (anti-hi.stamine)

Other, (Specify)

Hovz many hours sleep did you have last night? Was this suíicient2

VERY ITEM ActIve - energetic Angxy - annoyed Anxious - fearful

4: Bored - uninterestd

5 Cheerful - happy Decisive - capable Confused -- disorganized Disturbed - upset

Donhearted - sad

Drowsy - sleepy Dull - sluggish Easygoing - relaxed

Egotis Lic - boastful

Effective - efficient Genial - friendly 16,. Gloomy-blue

EI,1CLAB 225/68

A5

before now

17. Grouchy - irritable

before ñow 18. Humorous witty before now 19. Impatient - snappish

before now 20. Industrious - work-oriented

before now 21. Intoxicated - lightheaded

before now 22. Jittery - nervous

before now 23. Optimistic - high-spirited

before now 24. Pain - discomfort

before now 25. Quiet - peaceful

before now 26. Reckless - uninhibited

before now 27. Resentful - indignant

before now 28. Self-confident - courageous

before now 29. Sell-conscious - timid

before now 30. Sympathetic - considerate

before now 31. Talkative - chatty

before now 32, Tired -washed-out

Vlhich way of feeling did you like better7 before now

Please check here to indicate that you have answered every item,

Completing this list today was: DifficulLModerately difficult Moderately easy___

Easy r . be o re no befo r e no befo re no befo re .no. befo re no belo re flOE' befo re no before no befo r e no before nc before n before before befo re befo re before

Sec-i,nfv CI.is( rZìl,nn

FORM A

lNOVO1I473 (PAGE 1)

S/N OIO.OQ7.O Unciinss.jfjedSecurity CJs(icaton -

--- DOCUMENT CONTROL DATA R & D

flU,. body f .h.,,.rl .d l.-no, Up,- no.1 .nr..d wh.-,, r).. o..,,?! ..pn.r 1. t. OÑ'Of'. T,rtC.AC ri-VIT, (Cotpo'.fe .othorJ

Naval Ship Research and Development Laboratory

Anapolis;Maryland214O2

2e, REPORT SECURITY CLASSIFICATIOn

Unclassified

2).,

t) R9ORT TITLE

as a Functi'on of Ship Motion

CLOVER (AGDE 1)

of Human Operators

An Enitïëiñg Pycho1ogr Study Aboard USS

4.OESC RIPTiyOTES(2'pe,ofrpor! nd loc!o,,v de:..)

Researc'n arid Development Reoort

5. AJ THOR(S)(Fsr.t .rn.. udd1. irn:eI. i.,, r.me)

F. Warhurst andA. J. Cerasni

. REPORT Q*TE

Aprii 1969

7e. 'TOTAL NO. OF PACES

28 7h. NO. OF NEFS 2 )C. CONTRACT OR GRANT N, . PROJECNO. S4627-020 e. Task 13694 cT. _{Assigt A624-150}

ORATORS REPORT N)Jf8ER(51

2828

OTHER REPORT NOS) (Any othnr number. th1 .y b. eein.d

this i-r-port)

ELECLAB 225/6S

10, OISIR)BUTION STATCOENT

Each transmittal of this document outside the agencies of the U. S. Government must have prior approval of CO, NAVSHIPRANDL.B, Annapolis, Md. 21402

II. 5UPPLE.IENTARY NOTES 12. SPONSORING MILITANT ACTIVITY

NAVSEC (SEC 6165C)

.: .

:i.

.:

17. A5TN..CT

This study examines in an operatibal setting the hypothesis that human performance is significantly affected by ship's roll. Particular attention is paid to the nature and effects of roll stubilîzation equipmeñt The hypothesis is expanded to include the broad spectru.m of hrnan performance and the more subtle aspects of hip's motion.

Noteble finrlings include:

Ship motion causes au irrelevant stress on crew members. Some irrelevant stress may actually be beneficial.

The effect of roll stubilizatibn equipment is diphasic; it reduces intolerable roll amplitudes but tends to induce higher linear accelerations.

RoIl stabilization should be active from dead-in-water throughflank speed since mission requirements include extensive operations at lowspeeds.

TRLBUTION T TST NAVSEC(SEC 6165) (5) NAVSHIPS ÇPMS 78 P.2) NAVSHIPSÇPMS 78. 7) NAVSHIPS (SHIPS 033F) NAVSHTIPS (S}LLPS 03H) NAVSI-[IPS (SHIPS 0331) NAVS}IIPS (SHIPS 2052) (2) NAVSHIPS (SHIPS 06F) NAVSBIPS (SHIPS 031) NAVSEC (SEC 6104) NAVSEC (SEC 10343)

NAVSEC (SEC 6140E)

NAVSEC (SEC 6141) NAVSEC (SEC 6165C4) NAVSEC (SEC 6103D) NSRDC (CODE 042) NAVSE CPIULADW O' (CODE 455)

NAVET,X (CODE 05142E 1)

NAVORD (CODE 93315) DDC (20)

COMDESDEVGRU TWO

US NAVAL STATION NEWPORT, R.I. 0244

DR. J. C. TOWNSEND, DEPT OF PSYCHOLOGY,

CATHOLIC UNIVERSITY OF AMERICA, WASHINGTON, D.C. 20017 DR. WILLIAM WOOTEN, DEPT OF PSYCHOLOGY,

BROWN UNIVERSITY, PROVLDENCE, P.1. 02912