The High Speed Navy: Vessel Motion Influences on Human Performance

Michael E. McCauley, PhDEric C. Pierce, MA and Panagiotis Matsangas, MSNaval Postgraduate School and NSWC-Panama City

Ongoing Series of Analyses of High Speed Operations and Human Performance

Prior Analyses HSV-2 SWIFT FSF-1 Sea Fighter

Present Analysis Benchijigua Express (General Dynamics Team hull

for LCS)

Future, Planned Analyses LCS-1 Freedom (Lockheed Martin team) LCS-2

Objectives

In support of the LCS program, determine the influence of high speed vessel motion on human performance, safety, and health Vessel motion measurement Motion Sickness Incidence (MSI) Motion Induced Interruptions (MII) (biomechanics =>

posture, locomotion & tasks)

Identify problematic tasks & activities Contribute to operational envelopes

Benchijigua Express I.

Length 127 mWidth 30.4 mHull Trimaran (stabilized monohull)Draft 4 mSpeed 40+ knotsEngines Four 20V 8000 MTU engines provide

an output of 32,800 kW Propulsion Water jets & bow thrustersCapacity 1300 passengers and 340 autosDesign AustalApplication Ferry service in the Canary IslandsOperator Fred.Olsen, S.A.

Benchijigua Express

LCSCompeting Team Concepts

General Dynamics

Trimaran

Lockheed Martin

Semi-planing Monohull

Passenger Deck

Passenger locations were requested on the questionnaire surveys, indexed by seat color (see brackets in figure)

Bow

Instrumentation by NSWC-Panama City

6 DoF motion sensors installed at four locations on the passenger deck and two locations on the auto deck (mission bay)

GPS control box, video cameras, & video recorder

Seaway Data:Two Systems

Miros WAVEX system (radar)

TSK Wave Height Meter system (microwave)Output captured and stored in NSWCPC

control box

Questionnaire Items

Recent experience at sea MII Frequency & description MSAQ Seating location (by graphic) Open question– comments on ship motion

& comfort

Manual Dexterity Functional Range of Motion (FROM)

Peg placement task Manual speed (total time) and accuracy Two contestants compete for prizes

Procedures:Ferry Schedule

The Benchijigua Express began each day in La Palma a sailed a 2-hr transit to Tenerife

Multiple ½ hr transits during the day to La Gomera

Return each evening, 2-hr transit to La Palma Data were collected on the two 2-hr transits

each day for 10 days Supplemental data collected by Fred.Olsen crew

on the following 30 days

Procedures per Transit

Vessel motion sensors initialized Participants recruited for the FROM “game” One-hour after launch, questionnaires

distributed by the Fred.Olsen study coordinator to all passengers who agreed to participate

Bridge log data obtained Questionnaires collected prior to arrival

Data Set

86 two-hour transits

1,994 questionnaires

THANK YOU to the Fred.Olsen, S.A. personnel for their strong support in data collection

“Morning”: between 07:00 and 10:00 (aprox.)

“Evening”: between 20:00 and 22:00 (aprox.)

Motion Sickness: MSAQ

The MSAQ has 4 scales & totalG= gastrointestinalC= centralP= peripheralS= sopiteTotal

MSAQ Results

15

17

19

21

23

25

27

29

Inexperienced Some experience Good experience

MS

AQ

sco

re

0%

10%

20%

30%

40%

50%

60%

Per

cen

tag

e o

f p

arti

cip

ants

Participants [%] MSAQ Total MSAQ G MSAQ S

MSAQ Results

Passengers with recent experience at sea (>9 times in the prior month) were Less likely to respond to the questionnaire

(5% as opposed to 50%) Less likely to report motion sickness

symptoms, either gastrointestinal, sopite, or total MSAQ score

MSAQ: Morning versus Evening Transits

15

17

19

21

23

25

27

29

MSAQ Total MSAQ G MSAQ C MSAQ P MSAQ S

MS

AQ

sco

re

Morning

Evening

•All four subscales were significantly higher during evening transits.

•Sopite significantly evident in both transits (morning-evening)

MSAQ by Relative Heading of Seas

0%

10%

20%

30%

40%

50%

60%

70%

80%

0º

45º

90º

135º

180º

225º

270º

315º

MSAQ Total>11.2

MSAQ Total>20

MSAQ Total>30

Motion sickness greatest with head and following seas; least with beam seas

MIIs Defined

MIIs are interruptions in your balance, movement, or task performance, caused by ship’s motion. If standing, an MII could be slipping, sliding, losing your balance, not being able to walk, or having to grab hold of something to continue conducting your task. If seated, an MII could be holding your chair so as not to slide, holding onto objects to keep them from falling off a table, or unusual difficulty in using your computer keyboard or mouse. In general, whenever the ship’s motion makes you stop what you have been doing, even for a short amount of time, it is an MII.

MII Frequency by Relative Heading of Seas

2.5

3.5

4.5

5.5

6.5

7.5

8.5

HEAD Bow Beam QUARTERING Following

Relative wave heading

MII

s

0.008

0.01

0.012

0.014

0.016

0.018

0.02

0.022

Mean

vert

ical

RM

S a

ccele

rati

on

[g

]

Mean MII per hour RMS FROM [g]

MIIs per hour were least with beam seas, even though the RMS vertical acceleration was high with beam seas

MII Results & DiscussionOne type of MII is when an individual has to hold onto something to maintain their balance.

39% of the participants reported that this type of MII occurred at some time during their transit

This percentage was significantly higher during evening (43%) compared to morning (33%) data collection periods

The reason for this finding is unclear, but several factors may have contributed -- increased fatigue, higher proportion of alcohol consumption, and reduced external environment light conditions (lack of visual input – horizon)

Observed MIIs and the “Tipping Equation”

Analysis of the video data resulted in a frequency count of MIIs

The accelerometer data were used to compute the “Graham Tipping Equations” (Graham, 1990)

Results of this analysis showed that the tipping equations over-predicted MIIs by a factor of 47

The FROM Dexterity Task and Wave Height

0:00

1:12

2:24

3:36

4:48

6:00

1.60 2.82 3.75 3.83 3.84 6.03

Sign. Wave Ht. (m)

Tim

e (

min

)MEAN stand (min)

MEAN stoop (min)

Surprisingly, increased wave height did not influence FROM performance in either the standing or stooping positions. Participants were able to perform the task successfully, compensating for ship motion and MIIs

Summary and Conclusions I.

Motion sickness symptoms were reported by 60-90% of the participants, depending on wave height and heading

The reason that MSI was higher during evening transits cannot be determined from the data

Sopite syndrome is evident in all conditions These data on motion sickness are likely to be

consistent with military passengers, but not adapted crew

Summary & Conclusions II. Head seas resulted in more motion sickness

whereas beam seas resulted in more MIIs The motion effects of the Benchijigua

Express were relatively benign; given that it was operating at speeds in excess of 32 knots and that the participants were unadapted passengers rather than crew

The motion of this vessel did not interfere with manual dexterity performance