1
Design of High Speed Craft – The human factor
Dominic A. Hudson
School of Engineering Sciences, Ship Science, University of Southampton, Southampton, UK.
17th Annual Engineering Conference, Malta
17th April 2008
2
High Speed Craft Applications• Planing craft (up to ~80 kts) – now often RIBs
– Life-saving (e.g. RNLI in UK)
– Leisure
• Excursions, dive boats• Personal• Racing powerboats
– Military and para-military
– Offshore industry – variety of roles
3
What is the Problem?
4
100 102 104 106 108 110 112 114 116-2
0
2
4
6
8
10
Time (s)
Acc
ele
tatio
n (
g)
Vertical accleration at bowVertical acceleration at CG
slam impactno slam
slam at bow,no slam at CG
What is the Problem?
• Repeated shock impacts lead to:
– Lower back damage
– Knee injuries
• Depends on:
– Waves
– Hullform
– Boat speed
• 20 Kts
• Sea-state 3
5
Constant Speed Shuttle Run Test
636.9
1063.4
0 200 400 600 800 1000 1200
Pre
Post
Distance run (m)
• 12 subjects
• 8.5m RIB, 40 kts, 1hr 40 min
• Sea-state 0-1
What is the Problem?• Crew effectiveness
reduced:
– Physical performance
– Cognitive ability
• Factors:
– Day/night
– Temperature
– Sound
– Smell
– Everyone is different!
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Solutions?
• Currently design boats for:
– Speed, strength, range, weight, cost, etc.– Consider people later……… – EU Physical Agents Directive enforced
2010
• Can we design for people from the start?
• Or mitigate problems by
– Structural design?– Seat design?
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Research Effort• ~ 1 million EPSRC grant₤
• Univ. of Southampton – SES (Ship design)
– Prof. R. Shenoi, Prof. J. Xing, Dr. D. Hudson, Dr. S. Turnock, Dr. D. Taunton, Dr. J. Blake, S. Lewis, T. Coe.
• Univ. of Southampton – ISVR (Signal Processing)
– Prof. R. Allen, Dr. D. Allen
• Univ. of Chichester (Sports Science)
– Dr. R. Dyson, Prof. T. McMorris, Dr. T. Dobbins, S. Myers
• Additional funding:
Royal Academy of Engineering, School of Engineering Sciences
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Full-scale Tests• Measurement techniques
• Quantify/characterise– Motions– Vibration dose values– Physiological data
• Person in ‘real’ situation
Very difficult
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Full-Scale Results
67 67.5 68 68.5 69
-4
-2
0
2
4
6
8
Time (s)
Acc
ele
ratio
n (
g)
109.5 110 110.5 111 111.5
-2
0
2
4
6
8
Time (s)131.5 132 132.5 133 133.5-3
-2
-1
0
1
2
3
4
5
6
7
Time (s)
x directiony directionz direction
67 67.5 68 68.5 69
-4
-2
0
2
4
6
8
Time (s)
Acc
ele
ratio
n (
g)
109.5 110 110.5 111 111.5
-2
0
2
4
6
8
Time (s)131.5 132 132.5 133 133.5-3
-2
-1
0
1
2
3
4
5
6
7
Time (s)
Top 3 Acceleration Events at the CG
Top 3 Acceleration Events at the Bow
Results – VDV ‘action levels’
Comparison of Average 'Time to VDV Action levels' for all headings and axis
2.766
4.9536.380
2.356
5.887
4.1544.127
10.075
26.916
9.453
34.811
19.009
0.1641.451
6.268
0.516
6.181
2.979
0
5
10
15
20
25
30
35
40
Head Sea (at sea) Beam Sea (at sea) Following Sea (at sea) Head (in channel) Following (in Chanel) Total Average
Heading (location)
Tim
e to
VD
V A
ctio
n le
vel o
f 15
(h
ou
rs)
Time to 15 X Time to 15 Y Time to 15 Z
~10 mins
Results – Spinal health risk (ISO 2631-5)
Health Effect Predictions from Full Scale Trials Data
0
0.5
1
1.5
2
2.5
3
3.5
Record Attempt Working Life
Hypothetical Situation
Sp
ina
l H
ea
lth
Ris
k F
ac
tor,
R
Head Following Beam Lower Limit Upper Limit
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Full-scale ResultsHeart rate and Oxygen consumption
0%
10%
20%
30%
40%
50%
60%
70%
1 11 21 31 41 51 61 71 81 91 101 111
Time (minutes)
Perc
en
tag
e m
axim
al
Heart
rate
0%
5%
10%
15%
20%
25%
30%
35%
40%
45%
Perc
en
tag
e V
O2m
ax
heart rate VO2
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Numerical Modelling• 2D strip theory (after Zarnick)
• Wedge-impact model
• Non-linear, time domain
• Regular or irregular waves
• Well-known ‘conventional’ hulls
• Work on
– Validation
– Front-end GUI
• Limits
– hull form (RIB, VSV)?
– speed?
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Model Tests
• Validate numerical code
• 2 models tested
– Wave-piercing RIB ‘Kali’
– RNLI Atlantic 21 RIB
• Limitations
– Only head seas
– V. short run time (~3 sec)
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Results - comparison
33 34 35 36 37 38 39 40-2
0
2
4
6Full Scale
Time(s)
47 48 49 50 51 52 53 54-2
0
2
4
6
Acce
lera
tio
n (
g)
Model
39 40 41 42 43 44 45-2
0
2
4
6Numerical
CGBow
Current Work
Human spine model
Flow simulation
+ Design optimisation, ongoing model, full-scale testing
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See the Posters!
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Future Aims• Design boat to comply with EU directive
– Test boat = 21 mins
– ‘best’ planing hull = ~1 hour
– Target = 8 hours
• Co-operate with designers, builders, operators, MCA
• Understand human – boat interface
• Trusted design and simulation tools
• Tailor solutions to applications