goalds mhuss presentation 2010-09
TRANSCRIPT
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RULES AND STANDARDS
should define what is to be
achieved (safety of lives,property, functionality ...)
should express publicexpectations on performance
Rules Standards
provide a broad spectrum of requirements on design and
operation of ships that together will lead to an acceptable
level of safety
compliance with standards = fulfillment of expectations
Traditional IMO regulations are a combination
should provide a common
understanding of how thingsare to be done
should facilitateimplementation and
communication
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GOAL-BASED STANDARDS
Explicitly formulated objectives, functions andstandards distinguished from each other
Objectives are achieved by fulfilling functionalrequirements; standards are provided as solutions
May provide a generic scheme for the formulation ofrequirements and regulations for the future, that willfacilitate:
Safety monitoring and analysis
Alternative solutions
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MAJOR IMPACT OF SOLAS 2009
Harmonized assessment methodology for dry cargo
and passenger ships survivability after a collision
Ended a long era of prescriptive requirements ontransverse bulkheads and subdivision of passenger
ships based on floodable length and margin linecriteria
Reduced variation in actual survivability performanceand at the same time increased flexibility in designsolutions for passenger ships
Increased survivability of new ro-ro cargo ships andlarge passenger ships
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A PERFORMANCE STANDARD
The standard does not stipulate how the ship should
be subdivided, instead the performance of aproposed arrangement is evaluated for typicaldamage scenarios
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A PERFORMANCE STANDARD
The standard does not stipulate how the ship should
be subdivided, instead the performance of aproposed arrangement is evaluated for typicaldamage scenarios
The probabilistic methodology introduces a varietyof test scenarios that will cover real contactsituations better than a few representative test cases
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! ! !
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
p2
p3+4
p5+ p
6+ p
7+ p
5+6+ p
6+7+ p
5+6+7
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A PERFORMANCE STANDARD
The standard does not stipulate how the ship should
be subdivided, instead the performance of aproposed arrangement is evaluated for typicaldamage scenarios
The probabilistic methodology introduces a varietyof test scenarios that will cover real contactsituations better than a few representative test cases
The performance is on the other hand evaluated byrather generic criteria that may not fully cover everypossible chain of events after a flooding
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CORE COMPONENTS
1. Required overall level of survivability accountingfor any foreseeable situation where the ship haslost some of its watertight integrity (index R).
2. Distributions describing the degree of survivabilityunder a specific damage (s).
3. Distributions describing damage position andextent (p, r, v).
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DAMAGE POSITION AND EXTENT
Based on scattered collision statistics from a variety
of ship types and situations
Generic distributions coupled to length and breadthnormalized with respect to the stroked ship size;
Vertical extent described by a constant distribution(increased compared to previous for cargo ships)
Improvements: to include grounding (and other largescale flooding below the WL) in the genericdistributions
Recommendations: to maintain a simple and robustformulation of damage distributions
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SURVIVABILITY
The basis is a common format based on three
characteristics of the GZ-curve at equilibrium afterflooding (range, max, heel). Only heel differsbetween cargo ships and passenger ships
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GOALDS WS 2010-09-08, M Huss
SURVIVABILITY
The basis is a common format based on three
characteristics of the GZ-curve at equilibrium afterflooding (range, max, heel). Only heel differsbetween cargo ships and passenger ships
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0 5 10 15 20
Range
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
s
new GZ!0.12
new GZ=0.10new GZ=0.08
new GZ=0.06
new GZ=0.04
new GZ=0.02
existing GZ!0.10
existing GZ=0.08
existing GZ=0.06
existing GZ=0.04
existing GZ=0.02
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GOALDS WS 2010-09-08, M Huss
SURVIVABILITY
The basis is a common format based on three
characteristics of the GZ-curve at equilibrium afterflooding (range, max, heel). Only heel differsbetween cargo ships and passenger ships
Additional requirements for passenger ships forintermediate stages of flooding and heeling moments
Evacuation routes are to be effective after flooding
Improvements: could well be differentiated fordifferent arrangements and ship types as needed inorder to better describe capability; as long as thesurvivability measure is kept on a comparable level!
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REQUIRED OVERALL SURVIVABILITY
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In the case of passenger ships:
R =15,2252.5
5,0001s ++
!
NL
In the case of cargo ships greater than 100 m in length (Ls):
R =152
1281
s +
!
L
Previous SOLAS Ch.II-1 B-1:
R = (0.002 + 0.0009Ls)
1
3
Res. A.265(VIII):
R = 1!
10004Ls + N+1500
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
No of passengers (Ls=100,200,300,400)
Requiredinde
xR
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
No of passengers (Ls=100,200,300,400)
Requiredinde
xR
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
No of passengers (Ls=100,200,300,400)
Requiredinde
xR
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
No of passengers (Ls=100,200,300,400)
Requiredinde
xR
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REQUIRED OVERALL SURVIVABILITY
Is based on the weighted sum of survivability atthree different loading conditions (ds, dp, dl) that doesnot necessary follow the actual operational profile
Improvements: If we believe to have representative
models for damage distributions and consequenceswe should aim at harmonized also the safety levelrequirements
Future development: R could be expanded/dividedinto separate components (terms) to includedifferent safety targets (lives, property,environment ...)
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SOLAS 2009 AS DESIGN STANDARD
Increases dramatically the extent of analysiscompared to deterministic standards, but enablesmore flexible design solutions
Not ideal for easy design optimization but supportsidentification of safety critical design spots
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GOALDS WS 2010-09-08, M Huss
SOLAS 2009 AS DESIGN STANDARD
Increases dramatically the extent of analysiscompared to deterministic standards, but enablesmore flexible design solutions
Not ideal for easy design optimization but supportsidentification of safety critical design spots
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Consideration to meet higher damagestability standards
Additional watertight deck 8 abovefreeboard deck
Raise position of air vents from abovedeck 8 to above deck 10
Result (GM=1.4/1.0/0.85)
R = 0.663 A = 0.513 (vents above deck 8)
A = 0.739 (vents above deck 10)
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SAFETY LEVEL IN SOLAS 2009
A more consistent level of safety than in theprevious deterministic rules
The probabilistic standard has obtained an equalgeneral level of safety, and taking SOLAS 2009 as a
whole the level has been raised for most ship typesconcerned
Water-on-deck for ropax ships is still under dispute
since it is not explicitly targeted within the presentsurvivability criteria
Is the safety level sufficient?
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SUMMING UP THE STATUS
SOLAS 2009 has achieved:
harmonization of the methodology to assesscollision damage stability for dry cargo and
passenger ships
a more consistent level of safety and at the sametime increased design flexibility for passengerships
the basis for a clear structure that could beincorporated into a goal-based standard system
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SUMMING UP THE STATUS
SOLAS 2009 has not yet achieved (but could befurther improved and developed to achieve):
harmonization of damage stability assessment for
all types of flooding causes and all types of ships
fully comparable survivability criteria (s)
harmonization of safety level requirements (R)
the optimum regulation text
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