Paris March 2011 Probabilistic Damage Stability Rules for

Paris, March 2011 Probabilistic Damage Stability Rules for cargo ships and SPS (Part B – SOLAS 2009) Marine Technical Department Stability Section (DT 5)

CONTENTS q Probabilistic concept q Stability criteria to be satisfied q Parameters to be considered q Concepts for simplified analysis q Openings, controls & escape routes q Bottom damage q Minimum required GM q SOLAS 92 and SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 2

APPLICATION q SOLAS PART B – 1 q MSC. 281(85) : Explanatory notes to SOLAS CH II-1 q Dry cargo ships with type B freeboard L > 80 m, if constructed on or after 1 January 2009 L is the length as defined in the ICLL in force q For SPS : MSC. 266(84) : application depending on flag requirements. SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 3

PROBABILISTIC CONCEPT What is the basis of the probabilistic concept? q The probabilistic concept is based on the probability of survival after collision (damaged ship condition) q This probability of survival is expressed by the attained index A q The attained index A is obtained from the summation of the partial indices As, Ap, Al For which values of attained index A do we consider a ship as surviving? q The requirement for the survivability of the ship is set by the required index R q Therefore, the attained index A is to be compared with the required index R SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 4

STABILITY CRITERIA TO BE SATISFIED Four criteria need to satisfied for cargo ships/SPS 1. As ≥ 0. 5 R/0. 9 R, and 2. Ap ≥ 0. 5 R/0. 9 R, and 3. Al ≥ 0. 5 R/0. 9 R, and 4. A ≥ R Partial attained index q As : corresponds to the deepest subdivision draught ds q Ap : corresponds to the partial subdivision draught dp q Al : corresponds to the lightest subdivision draught dl SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 5

REQUIRED INDEX R FOR CARGO SHIPS Where: Ro = R as calculated for Ls > 100 m SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 6

REQUIRED INDEX R FOR PASSENGER SHIPS/SPS N= N 1+ 2 N 2 with N 1, number of persons for whom lifeboats are provided and N 2, number of persons the ship is permitted to carry in excess of N 1 N can be reduced to a minimum of N 1+N 2 subject to the agreement of the flag SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 7

ATTAINED INDEX A Each partial attained index is a summation of the contribution from all damage cases taken into consideration, using the following formula: Where: i : damaged zone or group of compartments under consideration c : the considered loading condition SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 8

FACTORS OF PROBABILITY Example: p(j=3) : represents the probability that only zone number 3 will be flooded taking into account the transverse subdivision (factors r 1, r 2, r 3) SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 9

FACTORS OF PROBABILITY Example 1: Calculation of damage cases Vertical limit: v 1 Penetration: r 1 Select the case which gives the smallest value for s: MIN {s 3; s 321} Case Nr Damaged spaces Transverse Vertical extent (r) extent (v) s-factor 1 3 r 1 v 1 s 3 2 3+2 r 1 v 1 s 32 3 3+2+1 r 1 v 1 s 321 SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 10

FACTORS OF PROBABILITY Example 2: Calculation of damage cases Vertical limit: v 2 = 1 Penetration: r 1 Select the case which gives the smallest value for s: MIN{s 34; s 3421} Case Nr Damaged spaces Transverse Vertical extent (r) extent (v) s-factor 4 3+4 r 1 1 - v 1 s 34 5 3+4+2 r 1 1 - v 1 s 342 6 3+4+2+1 r 1 1 - v 1 s 3421 SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 11

FACTORS OF PROBABILITY Example 3: Calculation of damage cases Vertical limit: v 1 Penetration: r 2 Case 6 a or 6 b depending on B/2 exceeding the CL or not Select the case which gives the smallest value for s: MIN{s 36; s 36251/s 362518} Case Nr Damaged spaces Transverse extent (r) Vertical extent (v) s-factor 4 3+6 1 - r 1 v 1 s 36 5 3+6+2+5 1 - r 1 v 1 s 3625 6 a 3+6+2+5+1 1 - r 1 v 1 s 36251 6 b 3+6+2+5+1+8 1 - r 1 v 1 s 362518 SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 12

PARAMETERS TO BE CONSIDERED q Watertight bulkheads and decks q Weathertight bulkheads and decks q Doors (watertight, weathertight of sufficient tightness and strength to restrict the flow q Air pipes q Ventilators q Piping systems q Horizontal evacuation routes q Vertical escape hatches q Controls: operation of watertight doors, equalisation arrangements, valves on piping or ventilation ducts, etc. ) q Permeability of spaces SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 13

PARAMETERS TO BE CONSIDERED Spaces Permeability at draught ds Appropriated to stores 0. 60 Occupied by accommodation 0. 95 Occupied by machinery 0. 85 at draught dp 0. 60 0. 95 0. 85 at draught dl 0. 60 0. 95 0. 85 Void spaces Intended for liquids Dry cargo spaces Container spaces Ro-ro spaces 0. 95 0 or 0. 95 * 0. 70 0. 90 0. 95 0 or 0. 95 * 0. 80 0. 90 0. 95 0 or 0. 95 * 0. 95 Cargo liquids 0. 70 0. 80 0. 95 * whichever results in the more severe Other figures for permeability may be used if substantiated by calculation SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 14

Specific requirements for SPS SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 15

CONCEPTS FOR SIMPLIFYING THE ANALYSIS V-lines concept Important factors for the calculation of the s-value: θe : Equilibrium heel angle θv : Angle where GZ < 0 or submersion of unprotected openings (downflooding point: openings cannot be closed weathertight) SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 16

CONCEPTS FOR SIMPLIFYING THE ANALYSIS V-lines concept The envelope curve of worst waterlines after damage for all the damage cases giving positive contribution to the attained index A Type of V-lines q “Watertight V-lines” derived from equilibrium heel angle (final or intermediate stages of flooding) q “Weathertight V-lines” derived from positive range (of GZ-curve) Input for the calculation of the V-lines q Bulkheads limiting the boundary of damage under consideration q Decks limiting the boundary of damage under consideration SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 17

CONCEPTS FOR SIMPLIFYING THE ANALYSIS V-lines concept Construction Scantling calculation (sufficient strength to resist flooding loads) Machinery No immersion of Weathertight openings Watertight openings Position of ventilators, air pipes Electricity Control of watertight doors, valves, etc. Safety Horizontal evacuation routes Vertical escape hatch V-lines from equilibrium V-lines from positive range Escape routes, etc. Stability Verification of progressive flooding SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 18

CONCEPTS FOR SIMPLIFYING THE ANALYSIS Safe Area concept q Area far away from side shell (damage) q Probability (r-factor) to have damage to area close to CL is very small q Piping system as much as possible positioned close to the CL q Maximum penetration is the boundary of the safe area (r 2) instead of CL q Way to simplify the investigation of progressive flooding q Negligible impact on attained index A: r 3 = 1 – r 2 is very small SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 19

CONCEPTS FOR SIMPLIFYING THE ANALYSIS No Safe Area q Investigation on progressive flooding for each damage case giving positive contribution to the attained index A q Fitting of valves to prevent progressive flooding q Maximum penetration is CL (or B/2) SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 20

CONCEPTS FOR SIMPLIFYING THE ANALYSIS Shadow of Tank concept CL CL Damage case: Damage in zone 1 3 Consequences: Damage in space 1 1 2 Damage of pipe Progressive flooding of space 3 SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 21

CONCEPTS FOR SIMPLIFYING THE ANALYSIS Shadow of Tank concept Damage case: CL CL Damage in zone 1 Consequences: 3 1 2 Damage in space 1 (No damage of pipe) (No progressive flooding of space 3) SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 22

CONCEPTS FOR SIMPLIFYING THE ANALYSIS Shadow of Tank concept CL CL Damage case: Damage in zone 2, up to r Consequences: 3 1 r Damage in space 2 2 Damage of pipe Progressive flooding of space 3 SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 23

CONCEPTS FOR SIMPLIFYING THE ANALYSIS Shadow of Tank concept CL CL Damage case: Damage in zone 2 Consequences: 1 3 rr 11 r 2 2 up to r 1: damage in space 2 (no damage of pipe, no progressive flooding of space 3) up to r 2: damage in space 2, space 3 and pipe SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 24

OPENINGS, CONTROLS AND ESCAPE ROUTES s = 0 (means: ship is not surviving), if position of q Air pipes, ventilators and openings closed by means of weathertight doors or hatch covers through which progressive flooding may take place q Horizontal evacuation route is below the waterline at final equilibrium q Vertical escape hatch q Controls for the operation of watertight doors, equalisation devices, valves on piping or on ventilation ducts intended to maintain the integrity of watertight bulkheads above the bulkhead deck q Any part of piping or ventilation ducts not fitted with watertight means of closure, carried through a watertight boundary is below the waterline in intermediate stages or at final equilibrium SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 25

OPENINGS, CONTROLS AND ESCAPE ROUTES s not automatically 0 if position of q Air pipes, ventilators and openings closed by means of weathertight doors or hatch covers through which progressive flooding may take place q Horizontal evacuation route and vertical escape hatch q Controls for the operation of watertight doors, equalisation devices, valves on piping or on ventilation ducts intended to maintain the integrity of watertight bulkheads above the bulkhead deck is above the V-lines q Any part of piping or ventilation ducts carried through a watertight boundary is fitted with valves able to prevent progressive flooding SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 26

SIMPLIFIED ANALYSIS – SUMMARY q V-lines concept q Safe Area concept q Shadow of Tank concept q Pipes and valves are adjacent to a bulkhead (longitudinal/transverse) or deck Provision: the separation distance is of the same order as the stiffening structure q Total cross sectional area of pipe < 710 mm 2 (where possible) Otherwise: q Investigation on progressive flooding for each damage case q If pipes and valves are outside the order of the stiffening structure, introduction of a gap or additional zone and investigation of progressive flooding SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 27

LOCATION OF VALVES AT BULKHEADS Example: or or SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 28

SURVIVABILITY FACTORS sintermediate and smom not applicable to cargo ships but to passenger ships/SPS SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 29

S intermediate and S mom SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 30

S intermediate and S mom → S intermediate to be calculated for passenger ships only if : ► progressive flooding / equalization before cross flooding greater than > 60 s ►Non watertight bulkheads restricting the immediate flow of water such as A class fire bulkheads, incenerator room, refrigerated spaces. SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 31

S intermediate and S mom SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 32

S intermediate and S mom SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 33

S intermediate and S mom SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 34

S intermediate and S mom SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 35

BOTTOM DAMAGE Double bottom height [m] h ≥ MIN{B/20, 2} hmin = 0. 76 Bottom damage NO SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 36

MINIMUM REQUIRED GM pr, v-factors s-factor Trim Geometry of watertight arrangement Loading condition VCG Operational trim range ≤ 0. 5% Ls Operational trim range ≥ 0. 5% Ls p: longitudinal direction Light draught (dl) VCGl Actual Partial draught (dp) VCGp 0 0 ≠ 0 with steps ≤ 1% Ls Deepest draught (ds) VCGs 0 0 ≠ 0 with steps ≤ 1% Ls r: transverse direction v: vertical direction If the attained index A = pr v s satisfies the stability criteria of SOLAS 2009, the minimum GM-curve is drawn based on the chosen VCGs SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 37

MINIMUM REQUIRED GM Minimum GM-curve = envelope GM-curve covering calculations for different trim values SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 38

2. SOLAS 92 and SOLAS 2009 ► SOLAS 1992 (cargo ships) l l l Calculations for 2 draughts (deepest & partial) No partial index requirements Permeability for cargo holds is constant and equal to 0. 70 Damage extent is up to CL Calculations are performed at even keel (trim = 0) ► SOLAS 2009 (cargo and passenger ships) l l l Calculation for 3 draughts (deepest, light service & partial) Partial indices Ai ≥ 0. 5 R Permeability of cargo holds is function of draughts and cargo type Damage extent is up to B/2 Calculations are performed for several trims if range of operational trims exceed +/- 0. 5% Ls (subdivision length) SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011 39

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