Workability limits and fatigue aspects on a Fast Patrol Vessel

Date Author Address

February 2009

Kapsenberg, G.K., 3.A. Keuning and 3.L. Gelling

Delft University of Technology

Ship Hydromechanics Laboratory

Mekelweg 2, 26282 CD Deift

TU Deift

Delft University of Technology

Workability limits and fatigue aspects on a Fast

Patrol Vessel

by

Geert K. Kapsenberg, Lex Keu fling and 3aap L. Gelling

Report No. 1610-P 2009

Published in: Proceedings of the International Conference

on Human Factors In Ship Design and Operation, 25-26

February 2009, Royal Institution of Naval Architects, RINA, ISBN: 978-1-905040-55-1

INTERNATIONAL CONFERENCE

HUMAN FACTORS IN SHIP

DESIGN AND OPERATION

25

- 26 February 2009, RINA HQ, London, UK

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HUMAN FACTORS IN SHIP

DESIGN AND OPERATION

Human Factors in Ship Design and Operation, London, UK

CONTENTS

Keeping The Human Element In Mind

i

D Squire, The Nautical Institute, Editor, Alert!

Empirical Models Relating Ship Motions, Sleep, Fatigue, Motion Sickness And

9

Task Performance In The Naval Environment

J Colwell, Defence Research And Development Canada - Atlantic,

Canada

The Case For Addressing The Human Element In Design And Build

19

A Sillitoe, O Walker And J Earthy, Lloyd's Register, UK

Human Factors Considerations For Marine Vehicle Design

29

J.M Ross, A/ion Science And Technology, USA

Intuitive Operation And Pilot Training When Using Marine Azimuthing Control

39

Devices - Azipiot

MLandamore And M Woodward, School Of Marine Science & Technology, Newcastle

University, UK

Talk And Trust Before Technology: First Steps Toward Shore-Based

Pilotaje

47

MLützhòfi And K Bruno, Chalmers University Of Technology, Sweden

Trade-Offs In Performance: Autonomous Unmanned Systems And Their Impact

55

On Human Performance

YMasakowski, Naval Undersea Warfare Center, USA

Impact Of The Control Of Noise At Work Regulations On Royal Navy

Warships

*

A Buckel!, Frazer Nash Consultancy, UK

Engine Control Room - Human Factors

61

P Grundevik, Sspa Sweden Ab, Sweden

MLundh, Chalmers University Of Technology, Sweden

E Wagner, Msi Design Ab, Sweden

Who Cares And Who Pays?

69

The Stakeholders Of Maritime Human Factors

C Österman, MLjung And MLützhôfi, Chalmers University Of

Technology, Sweden.

Developing Ergonomic Based Classification Rules

77

N Méry And J Mcgregor, Bureau Ventas, France

Human Factors in Sh4 Design and Operation, London, UK

Automatic Monitoring Of Various Ships' State Parameters.

85

R Imstøl, Bergen University College, Norway

A Human Factors Approach To The Design Of Maritime Software Applications

89

E Petersen, Lyngsø Marine AIS, Dk/Sam Electronics Gmbh, Germany

MLützhòfi, Chalmers Technical University, Sweden

Analyzing Human Error Triggered Accidents Onboard Ships Against Ergonomic

97

Design Principles

Y Song, Nippon Kayi Kyokai (ClassNK), Japan

Applying Complex Systems Theory To Develop An Adaptive Manning Calculus

105

That Preserves Operational Safety

C Comperatore And P Rivera, U.S.

'oast Guard, USA

Integration Of Human Factors Engineering Into Design - An Applied Approach

109

K Mcsweeney And J Pray, ABS USA

B Craig, Lamar University, USA

Workability Limits And Fatigue Aspects On A Fast Patrol Vessel

119

G Kapsenberg, Maritime Research Institute Netherlands, NL

JKeuning, DeW University Of Technology, NL

J Gelling, Damen Shipyards Gorinchem, NL

Ship Sense - What Is It And How Does One Get It?

127

JPrison, MLützh?fi And TPorathe, Chalmers University Of Technology, Sweden

Authors' Contact Details

131

* _{- Paper unavailable at timeof printing}

Human Factors in Ship Design and Operation, London, UK

WORKABILITY LIMITS

D FATIGUE ASPECTS ON A FAST PATROL VESSEL

G Kapsenberg Maritime Research Institute Netherlands, NL J Keuning, Deffi University of Technology, NL

J Gelling, Damen Shipyards Gorinchem, NL

Summary

Full scale measurements and observations were made onboard Her Majesty's Customs and Excise Cutter "Valiant". Objective of these measurements and observations was to find, with respect to the motion climate, practical limits to the use of this class of vessels. The measurements were carried out in December 2004 in the Itish Sea near Glasgow so that there was some guarantee of a significant seastate in the short measurement period available (Le. only 3 days).

This paper presents the results of the measurements on board the "Valiant" and discusses the analysis of the signals and the results of the observations on board, aimed at relating the motions to the human performance and comfort on board. The analysis is largely based on the approach as given in the ISO 2631:1997 standard "Evaluation of human exposure to Whole body vibration"; notably the root-mean-quad is used for the extreme events and the Vibration Dose Value is used to quantify fatigue on board. The problem of finding acceptable limits of the VDV for this crew of professionals will be

discussed.

One result of the observations is the importance of crew fatigue over a longer period compared to direct performance degradationdue to the motion climate.

1. INTRODUCTION

Knowledge of missiòn specific criteria is as important as

knowledge about vessel behaviour in waves. It is the

combination of these two aspects

that allows the

hydrodynamicist to assess the suitability of a ship for a specific task or the evaluation of two different ships for the same task.

This insight is not exactly new, but research on criteria is much less developed than research on ship motions. The

reasons are clear as also illustrated by this article; the

'experiment' is less well defined due to lack of control

over the environment and a large number of

measu-rements are required to reach some level of certainty due to the variability in human species.

These difficulties have led to simplifications of the

problem to reduce the number of parameters. Although this is a perfectly legitimate scientific approach, the risk

is very high that the results of the simplified tests are

directly generalized to the real problem (by lack of

alternatives). A good example are the simplified tests

carried out by O'Hanlon and McCauley [13] who

subjected a group of healthy young male college students

to sinusoidal vertical motions in a cage. From these results they developed the Motion Sickness Incidence (IVISI), a parameter that expresses the percentage of persons that vomited within the 30 min test duration.

These results are generalized to passenger comfort

onboard - for instance - a cruise vessel and to a motion climate that consists of a range of frequency components

and for a duration that is considerably longer than

O'Hanlon's test period.

©2009: The Royal Inst itution ofNth'al Architects

The objective of these trials was to evaluate parameters

for limits to the ship motion environment that were

acceptable for the crew. Such tests are specific for the

type of vessel,

or more specific: to

the type of

acceleration climate. In this case the vessel is relatively large and not as fast as other High Speed Craft (HSC),

but defmitely a different

class as a conventional

displacement vessel. For this type of vessel, and for these crews (commonly professionals), the limiting factors are not only motion sickness or danger for musculoskeletal injury but mainly to avoid extreme (slamming) events

and Motion Induced Fatigue (MTF).

Among hydrodynamicists there is a strong tendency to express the workability of a ship including the human performance factors (HF) in singleparameters and values.

Quite understandably so, but quite a few aspects involved

with these HF are not easily or objectively captured like

that, as will be discussed later.

2. THE SHIP AND INSTRUMENTATION

The ship used during

the measurements, i.e. Her

Majesty's Customs and Excise Cutter (HMCC)

"Valiant", is a Damen Shipyards "Stan Patrol 4207"

design, Fig 1. This design is built along the lines of the so called "Enlarged Ship Concept" (ESC) developed by

Delfi University of Technology in the late 90's. This ESC implies that the ship is considerably longer than

strictly necessary for the required accommodation whilst

maintaining

the same beam and speed

as more

conventiOnal ships. The main particulars of the ship are

given in Table 1.

120

Fig i Picture of HJvICC Valiant (www.caithness.org)

The ship has been equipped with active stabilizer fins

which were used during the trials. Large roll angles were therefore not encountered during the tests.

Because of the specific objective of the test campaign, it was not required to measure the wave environment; the

objective was to fmd clues to the relation between the

motion climate and the well-being of the crew.

The instruinéntation consisted

of GPS

receivers,

accelerometers and rate gyros. Two vertical

accelero-meters were sampled with a high rate of 500 Hz; one of

these was positioned at the base of the fire monitor on the fore deck, the second was positioned inside the

wheelhouse on a transverse beam, about 0.5 m in front of

the feet of the helmsman.

The low frequent system (sample rate 50 Hz) was

positioned at the back of the wheel house; it consisted of

3 linear and 3 angular accelerometers and aimed at

measuring the ship motions. Engine revs and rudder

angle were taken from the ship data acquisition system;

values were recorded at a rate of approximately 0.5 Hz.

In addition a video camera was installed in the wheel

house looking forward to record the relative motions and

possible occurrence of spray and green water at the bow.

The measurement system was started as soon as the ship left harbour; measurements continued over the entire day.

The measurement runs

were selected from these

continuous recordings.

Table i Main particulars HMCC "Valiant"

Human Factors in Ship Design and Operation. London, UK

3. THE TRIALS

The trials were conducted in December 2004 in the

northern Irish Sea, Fig 2. The ship was instrumented on

Day 1, the instrumentation was tested on a very quiet

Day 2 and very useful measurements were done on Day 3 and especially on Day 4. Nights were spent in harbour; in the morning the first hours were needed to sail to the

trial area. Trials continued usually to sun set at about

16:00 hr (UTC).

The weather conditions were on Day 3: wind SSW Bf 5, waves about 1.0 - 1.5 m significant wave height and on

Day 4: wind S Bf 7-8 and waves 2 - 3 m. It should be noted that the wave height is based just on a visual estimation backed by the infonnation obtained from a

local environmental website used by the crew on board.

The trials consisted of individual runs of 20 - 30 min each at one headingand one speed. The main focus of

the project was on the conditions on-board in head seas. Some runs were done in beam seas and stern quartering seas to assess the effect of roll motions and to consider

the controllability in stern quartering seas, i.e.

considering a possible tendency to broaching. The crew was not working as normal: i.e. patrolling the coastline,

combat smuggling and enforcing Custom controls.

During the measurements these tasks were suspended. The usual operational tasks associated with sailing the

ship were of course carried out as usual.

Next to measuring the motions of the vessel as described

above, the crew was observed for their behaviour and

response to the conditions

on board. No formal

questionnaires were used in this process.

Fig 2 Trial area (red circle) in the Northern Irish Sea

just south of the Isle of Arran.

During the entire measurement period no unacceptable

(by the crew) large slams did occur, so also no real

extreme peaks in the vertical accelerations. Therefore the crew did not intervene during the runs by reducing power or changing course. Apparently the motions, impacts and spray were considered workable and safe by the skipper

and crew.

©2009: The Royal Institution ofNaval Architects

Description Abbr units value

Length over all Loa m 42.80 Length between

perpendiculars Lpp m 39.00

Beam B m 7.11

Draft T m 2.52

Depth D m 3.77

Freeboard at the bow Fb m 2.79

Displacement A ton abt. 200

Metacentric height GM m 1.25

Propulsion power - 2x

Caterpillar 35 16B PBKE kW 4176 Trial speed V1 kts 26.4

Human Factors in Ship Design and Operation. London, UK

It should be noted that the speed during the runs was

never equal to the trial speed of the ship, the maximum attainable speed varied from 22 to 24 knots, depending on the conditions and heading.

THE SHIP CONCEPT

The ship is a so-called ESC (Enlarged Ship Concept) as developed by Keuning [9, 10 and 11]. Themain idea is to

make the hull longer than strictly necessary from the

point of view of the internal arrangement. This allows a certain amount of void space in the fore body enabling a much fmer hull with a higher deadrise angle and much

sharper and deeper sections in the fore body. As a

consequence slamming is far less severe than for a more conventional vessel as is illustrated by a comparison of

the positive and negative

peaks of the

vertical

acceleration. According to linear theory these peaks should be equally large, but due to slamming in the

downward motion, the positive peaks can be 4-5 times

larger than the negative peaks for conventional fast

vessels. For the ESC the ratio is much more favourable as illustrated in Fig 3. This figure is based on the results of the reported tests sailing in head seas with a maximum

speed in the prevailing conditions. Some moderate

slamming was recorded as will:bediscussedlater.

loo -D 2 0 _lo lo L r r L r r j-r L r r E E L L Pos peaks INegi peaks r a-I.. r r 4-10 E t-r L E T T -E ©2009: The RoyàlJnstitùfioñofd'í"alAròhitects

The idea behind the accelerometer at the basis of the fire monitor on the fore deck was to also to detect whether slamming events could be identified from the resulting ship vibrations, as is customary procedure with "normal"

commercial vessels. The results hereof however were

disappointing: it was difficult to detect actual slamming events this way. The power spectra of these two sensors

are depicted in Fig 4. It shows the low frequent ship motions (up to 0.5 Hz) and a peak in both spectra at

around 5 Hz, which is probably the 2-node global

vibration mode of the ship, and some peaks at 14 and 26

Hz at the bridge and 17 Hz at the bow. These are

probably local vibration modes. It should be noted that these fast patrol boats are usually quite stiff with much

higher natural frequencies when compared to normal

commercial ships.

An attempt to visualise a slamming and whipping event has been made in Fig 5 here to high frequent part (f> 1 Hz) of the acceleration signal is plotted. However, not all

high frequent parts could so easily be identified as a

slammingand whipping event. l0 I O E 2 10 o O) 0. o O lo > lo_I l02 40 -20 bridge bow E

j

J J E -40 711 711.2 711.4 711.6 711.8 time (el

Fig 5 High frequent oscillation in the vertical accelerations at the bow due to slamming.

712

121

0 5 10 15 20

Acc (m/s21

Fig 3 Distribution of the positiveand negative

extreme values of the vertical acceleration

on the bridge.

ANALYSIS OF THE SIGNALS

The high frequent (500 Hz) vertical accelerometers were placed at the strong and rigid basis of the fire monitor on

the foredeck and in the wheelhouse. The signals were used for the assessment of the ships operability: at the

bow to detect slamming and at the wheelhouse to

determine the Motion Sickness Incidence (MSI), the Vibration Dose Value (VDV) or other "acceptance"

parameters

40 50 0 lO 20 30

frequency [Hzl

Fig 4 Power spectra of the vertical

accelerations on the fore deck and on the bridge.

122

6. EVALUATION METHOD

Evaluation methods are described in two different

standards: the British Standard Guide BS 6841:1987 [2] and the ISO standard 2631-1:1997 [6]. Both standards

intend to evaluate whole body vibration and repeated

shock. In very broad terms they follow the same

procedure: there is a frequency weighting, or filtering, of

the input acceleration signal and - depending on the

relative crest value of the signal - parameters are defined

that intend to quantify health and fatigue aspects for

humans. The frequency weighting depends on the

direction of the linear acceleration.

When applying these methodologies there are quite some differences as discussed byGriffin [5] and Lewis [12].

The first step in the evaluation is to apply a frequency

weighting to the input signal. For people standing upright,

this is at their feet. The analysis in this paper follows the frequency weighting as defmed in the ISO 2631-1:1997

(the Wk weighting factor). This weighting works as a band filter. The main frequency range for which the

method is sensitive is from 2 till 30 Hz. This means that the ship motions in the 'normal' range of wave &ncounter

frequencies, i.e. between 0.2 - 0.4 Hz, have a limited effect on parameters that are based on this weighted

signal. A plot of the weighting factor is given in Fig 6; the plot also shows the weighting factor as given in the BS 6841:1987 standard.

Depending on the relative crest value of the signal,

different parameters need to be used for further analysis.

The relative crest value of the signal is defmed as the

crest factor C'fi

cj'

krfreme (1)

nns a,,,

in which a,,, is the frequency weighted acceleration signal.

For signals with a low Cf value (Cf< 6 according to BS

6841 and Cf < 9 according to ISO 2631) it is

recom-mended to use the "running RMS method" as the

relevant parameter for motion discomfort and fatigue

assessment. This method is based on the integral of the filtered acceleration signal squared.

For signals with a high Cf value the Vibration Dose

Value (VDV) is recommended. This method puts a much higher weight to the extremes in the acceleration signal

by considering the integral of the filtered acceleration

signal to the power four.

Noted is, that models to determine damage to the lumbar spine use a sixth power acceleration parameter, see the ISO standard 263 1-5 [8] and Peterson [14]. Such models

are applicable to another category of craft, i.e. much

smaller and much faster. On the present ship these items

were irrelevant.

Human Factors in Ship Designand Operation, London, UK

t) 42 1.4 1.2 1.0

08

0.6 0.4 -L t-

t

-0.2 ----1

-01 1 10 100 frequency [l-e]

Fig 6 Frequency filtering according to ISO standard

263 1:1997 and British standard BS 6841.

The effect of the

filtering by using the frequency

weighting function on the measured signal is shown in Fig 7. It effectively filters the very high frequencies and so reduces the highest values measured, these extremes may be due to dynamic effects in the accelerometers or

due to dynamic effects iii the structure on which the accelerometer is mounted. The method also filters the

low frequent part generated by the ship motions as may

be seen from the same plot.

Whether the high peaks with short duration have any

physical meaning or not is a long lasting debate among the experts. The pulse duration is a relevant parameter

for the peaks, because this determines the amount of

energy. Short duration peaks are effectively removed by the filtering method, this seems the proper approach in

applying the signal to assess FIF, but it should not be

done to assess structural effects like peak stresses and

structural fatigue aspects. Most likely the human

interpretation of the severity of the slam and hence the basis of the decision to reduce speed or not, is governed

by the perceived structural consequences of the impact.

20 10 5 12 G) Measuid signal Filtered signal

1_

_{1402 1402.5 1403 1403.5 1404 1404.5 1405 1405.5 1406}

LI!I i::

tIme [SI

Fig 7

_{Effect of filtering on the}

signal (Vacc bridge).

The running RMS method is based on an integration of

the weighted acceleration signal squared over a short

interval, see equation (2); it is recommended (ISO 2631) to use t = i [s].

acceleration

©2009: The Royal Institution ofNa val Architects

lSO2631:1997 BS6841

15

C', (n

Human Factors in Ship Design and Operation, London, UK

©2009: TheRòj41i$tItZ4tiQ7f14rchitects

500 1000 1500

time [s]

Fig 8 Vibration Dose Value development durin a run.

The blue line shows the base function 0.2

7. RESULTS OF INDIVIDUAL RUNS

All runs have been analyzed by the following procedure:

Frequency weighting of the acceleration signal

Determining the RMS value Determining the crest factor

Determining the VDV20 value

The results of this analysis are presented in Table 2 and

Table 3.

Table 2 Results of the runs on Day 3

Table 3 Results of the runs on Day 4

In which:

Hd - Heading relative to the waves: Head= 180 deg indicates head seas, Head = 90 deg is beam seas on the SBside etc

Trun - Duration of the run

123 N 1 23 180 20 7.2 1.19 1.13 3.87 2 23 0 15 6.6 0.88 0.85 3.06 3 12 180 20 11.4 0.39 1.47 3.36 4

18

180 35 11.9 0.48 1.84 4.09 5 18.5 45 30 7.3 0.29 0.76 2.44 6 18.5 90 20 6.0 0.30 0.63 2.42 1 15 180 20 21.3 0.50 2.34 4.94 2 24 180 18 9.4 0.57 1.70 4.84 3 19 90 25 5.1 0.48 0.95 3.75 4 14 0 30 7.4, 0.10 0.32 0.86 5 16 180 25 16.1 0.65 3.03 6.18 6 16 225 20 7.9 0.62 1.66 5.15 7 16 30 26

56

0.31 0.95 253 rRMS(t0)=

{!'Ì[w ()]2

dt} (2) The Maximum Transient Vibration Value (MTVV) is

defined as the maximum value of a(to) over the

measurement time.

The VDV parameter is used for signals with a high crest

factor. The parameter uses the fourth power of the

weighted acceleration signal because it is believed that especially the peak values of the acceleration are most important for the determination of the operability limits.

The defmition of the VDV parameter is defined by:

T

VDV =

{J[aw(t)] dt}

(3)

Equation 3 shows that

the VDV rarameter

is

continuously growing in time; if [a(t)] would be a

constant, the curve is a fourth power root function. An example of the VDV development and the basis function is shown in Fig 8. The curve clearly shows the moments of large impacts where the VDV increases in a veiy short

period.

A fundamental difference between the weighted RMS

value and the VDV is that the first is a sort of average that can be independent of the time, while the second

quantifies a dose value, so it is a function that keeps on

growing. When comparing two VDV values

it is

therefore essential to define the time period over which

the measurement is rnade The runs carried out in this

campaign varied in length; the choice has been made to

use the full length of the record and to 'normalize' the

result to a run dUration of 20 minutes using:

VDJ'ZO =fl» (20 '\'

_jJ

(4) in which: ti actual duration of the run [mini.

As an alternative parameter of evaluating the severity of the motion climate on the bridge, the running root-mean-quad is. used. This parameter is defined in a way similar to the running RMS method:

rRMQ ('e) =

[a (t)]4

(5)

For r also a value of r = I [s] is used.

The main reason to use the rRMQ parameter is to have a quantity to assess individual extreme events as illustrated later in this paper.

124

The results of the analysis clearly show that really high

crest factors (Cf> 9) only occur in head seas. The Cf

factor is higher than 6 for almost all runs. This result and the subjective experinnce of the 'bumpiness' of the ride suggest that the ISO limit of Cf> 9 is more appropraste than the BS limit.

Run 5 on Day 4 was the exceptional run in the sense that the crew believed that the vessel was sailed to the limit of acceptable motions. This, amongst others, was confirmed by the observation that now the commanding officer was at the controls himself. Although the ship was running under autopilot, he kept his hand above the power setting controls, being ready to reduce power within a second

when considered necessary. This confirmed earlier

fmdings that the occurrence of one big slam would lead to a voluntary speed reduction by the crew to prevent it from happening again. However no such slam or such intervention occurred during this particular run.

The severity of the motions during this run was such that the crew indicated they would normally not continue at this speed (16 kts) in these conditions. When asked, the commanding officer replied that he would not increase the speed in these conditions at this heading because of the danger of shipping green water and damage on deck.

Quite noticeable he did not mention slamming!

rRMQ O Recorded events

During this run a few seriOus impacts occurred, at least

according to the observers. The instant they occurred

they were manually recorded.

This was a rather

subjective and not a very accurate recording by one of the observers, not by the crew. An attempt was made to associate the recorded events with the measured motions; Fig 9 shows the running root-mean-quad of the entire run

and the recorded extreme events. There is a good

correlation between the 5 extreme peaks of rRIvIQ of the acceleration signal and the slamming events. Fig 10 and Fig il show a zoom-in on two events, especially Fig 10 shows that the event is followed by structural resonance

(whipping) on this location, ie. the wheelhouse (the

bridge), also an indication of the severity of the slam.

Human Factors in Ship Design and Operation, London, UK

15

N10

C 5 o CI -5 -10 Fig 10 Zoom-in Day 4. w o j. lì" -I- - - - + - - - -!; 298.5 299

j

Filtered sIgnal O Recorded ents 8. FATIGUE EFFECTS

Fatigue aspects clearly played a role for the crew. The

two days of the actual tests were quite intense in the

sense that the people carrying out the measurements were

continuously pushing for the limits of acceptable ship

behaviour. Although just a limited time was spent in the

most demanding conditions as can be deduced from Table 4, the measurement crew noticed an increasing

amount of irritation among the crew; it is believed this

was caused by Motion Induced Fatigue.

Actual seasickness was not an issue for this professional crew. The appetite during the hot lunch was quite good and quite some time was dedicated to cooking and eating,

this required a very comfortable course and speed

combination.

i

I-1080 1082 I-1072 1074 1076 1078 time [s]

Fig 11 Zoom-in on the 4th recorded event: Run 5, Day 4.

©2009: The Royal Institution ofNaval Architects

T T 1

Ii

r-r T

i

i

i 20 Fiiteredslgn

'O' Recorded eents

15

10 I -1 -1

t--5 -i L -J -I

500 1000 1500

time (ej

Fig 9 Running Root-Mean-Quad on the bridge and recorded extreme events, Run 5, Day

4.

5,

299.5 300 300.5 301 301.5

time [s]

on the l' recorded event: Run

N_n

Human Factors in Ship Design andOperation, London, UK

Table 4 The events in Day 4

In order to quantify fatigue effects, the VDV was

calculated for the complete day, Fig 12 shows the results

over the two days of the actual measurements. The

curves clearly show the different events during the days

as detailed in Table 4 for day 4. The figures show that day 4 was 'heavier' than day 3;, the cumulative VDV

over all the day was 6.43 for day 3 against 8.42 for day 4.

It can also be noted that on day 4 we surpassed before

lunch already the total VDV of day 3!

9 8 7 6 Ç .-', 5

>3

o o -J

f

©2009: TheROyaIh7$titUtlQflòPNrn'alÁrchitects

cabins on board should therefore be optimized with

this aspect in mind.

Dining the runs in the harsher conditions it became quite crowded at the wheelhouse, because both the

measurement crew and the crew of the

ship

obviously preferred to "rideout the run" there. From interviews with crews it became apparent that this preference originates from the fact that they like "to

see it coming" as well as the reduced inception of

sea sickness because of the visibility of the horizon. Also the wheel house longitudinal position in this

design Was optimized for minimal motions. A design consideration however then becomes: is your wheelhouse big enough?

The quality of life on board of these ships is strongly

influenced by the possibility to prepare meals and eat properly. This implies good positioning of the

galley and thü mess room and minimal motions

during thepreparationsand eating.

Smalldetails may have a.big inflùence in this respect,

such as proper handholds, effective fiddles in galley

and mess room, no sliding

lockers in athwart

direction, proper book holds, not too beamy open

spaces, proper chairs, possibilities to lock doors both open and shut, etc.

None of the crew mentioned the effect of spray as a problem. This despite the fact that due to the bow

shape applied (the ESC concept) the spray hitting the

wheelhouse windows was quite substantial in some

of the harsher conditions.

Good sound insulation has a strong effect on crew

well being.

10. INDICATIONS FOR RELEVANT

PARAMETERS AND LIMITING VALUES

The present study serves only as a starting point of

choosing adequate parameters to assess workability

limits and fatigue aspects on board high speed vessels;

Neverthuless, we derived some indications; These results

are too unique to call these indications "Conclusions";

measurements and observations on more vessels are

required. Our indications are here presented as a set of

statements:

Runs in head seas are clearly the most critical ones if the parameters in the assessment methods are based

on vertical accelerations.

For this ship in these conditions it appears that the Vibration Dose Value is an appropriate parameter to

evaluate the workability of the ship in terms of

fatigue effects. It appears that a value of VDV = 8.5 m.s75 is a maximum for thisshipsaiing its mission.

To assess the severity of single impacts the running Root Mean Quad parameter is proposed. It appears that an event with a RMQ valúe of 2.5 m.s'2 should

be considered as a limiting value.

An event recorder in the sense of a manually

operated push button to record special eveflts on the

125

Time interval Event

0-2:10

In transit at low speed

2:10 - 2:30 Test run at high speed in head seas

2:35 3:00

Test run in beam seas

3:00 - 3:30 Test run in following seas

3:30 - 4:20 PreparatiOn of lunch; Lunch

4:20 - 4:45 Test run in head seas at high speed

4:50-5:10

Testruninbowquarteringseas

Test run in stem quartering Waves 5:30 5:55

5:55 - 620 Transit

1 2 3 4 5 6 7 8

time Ihn

Fig 12 Vibration Dose Valúe developmenton days3

and 4.

9. SOME OBSERVATIONS ON HUMAN FACTORS

Apart from the level of vertical accelerations on board of the ship and the evaluation methods based upon these, there were all kind of other aspects with the design and the operation of the ship, which appeared to influence the human factors on board during the test days. In the light of this paper a few of these aspects will be mentioned to

highlight the importance of these "details" and their

possible effect on the workability of the ship.

Properrestfor the cresÑ is crucial to redücethe effect

of motion induced fatigúe. Interviews with other

crew showed that facilities on board to rest properly have significant effect on the acceptance or tolerance levels with seçt tO mOtions. The location of the

I

J

Day 4 2

126

data acquisition system is a very useful addition to a measurement system where the supposed "expert" is

present.

Ill. ACKNOWLEDGEMENT

The very helpful cooperation with the UK Customs and

Excise department and in particular the crew of the

"Valiant" was greatly appreciated and thankfully acknowledged.

12. REFERENCES

1. Bos i.E. and Bies w., 2000, Performance and

sickness.at sea, RINA Conference Human Factors in ship design and operation, 2 7-29 Sept, London.

2. British Standard Guide to Measurement and evaluation of human exposureto whole-body

mechanical vibration and repeated shock, BS 6841:1987.

3. Dallinga R.P, Pinkster D-J. and Bos i.E., 2002, Human factors in the operational performance of

ferries, RINA Symposium "Human Factors in ship

design and operation II' London

4. Dobbins T., Rowley I. and Campbell L., 2008, High speed crafi human factors engineering design guide, Human Sciences & Engineering Led, Report

ABCD-TR-08-01 vi.O.

5. Griffin M.J., 1998, A comparison of standardized

method for predicting the hazards of whole-body

vibratiOn and repeated shocks, Journal of Sound and Vibration (215)4, 883-914.

6. ISO 263 1/1-3, 1985, Mechanical vibrationand shock

- Evaluation of human exposure to whole body

vibration.

Part 1: General Requirements.

Part 3: Evaluation of exposure to whole body z-axis vertical vibration in the frequency range 0.1 - 0.63 Hz.

7. ISO 26314, 2001, Mechanical vibration and shock -Evaluation of human exposure to whole body

vibration - Part 4: Guidelines for the evaluation of

the effects of vibration and rotational motion on

passenger and crew comfort in fixed-guideway transportsystems.

8. ISO 263 15, 2004, Mechanicaivibration and shock -Evaluation of human exposure to whole body vibration - Part 5: Method for evaluation of vibration

containing multiple shocks.

9. Keuning, J.A., Pinkster, Jakob, "Optimisation of the

seakeeping behaviour of a fast monohull" Fast '95. conference, October 1995.

10. Keuning, J.A., Pinkster, Jakob, "Further design and

seakeeping investigations into the "Enlarged Ship

Concept". Fast '97 conference, July 1997. 11. Keuning J.A., Toxopeus S. and Pinkster J., 2001,

The effect of bow shapeon the seakeeping

performance of a fast monohull, 6th Lnt Conference

Human Factors in Ship Design and Operation, London, UK

on Fast Sea Tranportation FAST 2001, 4-6 Sept, Southampton.

Lewis C.H. and Griffm M.J., 1998, A comparison of evaluations and assessments obtained using

alternative standards forpredicting the hazards of whole-body vibration and repeated shocks, Journal

of Sound and Vibration (215)4, 915-926.

O'Hanlon i.F. and McCauley M.E., 1974, Motion

sickness incidence as a function of the frequency and acceleration of vertical sinusoidal motion, Aerospace medicine, April 1974, pp 366-369.

Peterson R. et ai, 2008,HighSpeed Craft Health Monitoring System, Pact/ic 2008 Ini Maritime Conf

(IMC), ABCD Human Performance session, 29-31 Jan 2008, Sydney.

- 15. Tipton M., Eglin C., Golden M. and David G., 2003,

The performance capabilities of crews of daughter

craft involved in offshore operations in the oil and gas industries, HSE Report 108.

Turan O., Ganguly A., Aksu S. and Verveniotis C.,

2003, Human comfort and motion sickness on board high speed crafts, FAST 2003 conference, 7-10 Oct 2003, Ischia, Italy.

wolk H.L. andTauber J.F., 1974, Man's performance degradation during simulated small boat slamming, NSRDC report 4234, Jan 1974.

13. Author's biography:

Ceert K. Kapsenberg is now Principal Researcher

"Impulsive loads" in the MARLN R&D department. He

worked before in the seakeeping department on high

speed vessels in both commercial and research projects.

J. A. ( Lei) Kenning is an Associate Professor at the

Ship Hydromechanics Department of the Delft

University of Technology and specializes in advanced

marine vehicles and sailing yachts.

Jaap L. Ceiling is head of the High Speed Craft

Department of DAMEN Shipyards in Gormchem, The

Netherlands