Comparisons of model experiments to determine survivability limits after damage on roll-on roll-off passenger ferries

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Comparisons of model experiments to determine survivability limits

after damage on roll-on roll-off passenger ferries

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Institute for Ocean Technology

Institut des

technologies oc ´eaniques

Laboratory Memorandum

LM-1996-01

Comparisons of Model Experiments to Determine

Survivability Limits After Damage on Roll-on Roll-off

Passenger Ferries

C. Smith

March 1996

Smith, C., 1996. Comparisons of Model Experiments to Determine Survivability Limits After Damage on Roll-on Roll-off Passenger Ferries. St. John's, NL : NRC Institute for Marine Dynamics, LM-1996-01.

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■"*■

Canada

National Research Council

Canada

Conseil national de recherches

Institute for Marine Institut de dynamique

Dynamics marine

u

COMPARISONS OF MODEL EXPERIMENTS

TO DETERMINE SURVIVABILITY LIMITS AFTER

DAMAGE ON ROLL-ON ROLL-OFF PASSENGER FERRIES

LM-1996-01

U

Claire Smith

March 1996

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REPORT NUMBER

LM-1996-01

NRC REPORT NUMBER DATE

March 1996

REPORT SECURITY CLASSIFICATION

Unclassified

DISTRIBUTION

Unlimited

TITLE

Comparisons of Model Experiments to Determine Survivabiiity Limits after Damage on Roll-on Roll-off Passenger Ferries

AUTHOR(S)

Claire Smith

CORPORATE AUTHOR(S)/PERFORMING AGENCY(S)

Faculty of Engineering

Memorial University of Newfoundland

PUBLICATION

Workterm report __

SPONSORING AGENCY(S)

Institute for Marine Dynamics National Research Council

IMD PROJECT NUMBER

743 NRC FILE NUMBER KEYWORDS ro-ro / ferries PAGES 11, Apps. A-B FIGS. 10 TABLES 6 SUMMARY

This report describes a review of model experiments carried out in support of the IMO panel

of experts on Ro-Ro Safety.

address National Research Council Institute for Marine Dynamics P. O. Box 12093, Station 'A1 St. John's, Newfoundland, Canada A1B3T5

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LM-1996-01

TABLE OF CONTENTS

LIST OF TABLES AND FIGURES v

1.0 SUMMARY.... 1

2.0 INTRODUCTION 1

3.0 MODEL DESCRIPTIONS 2

4.0 UNITED KINGDOM AND SCANDINAVIA 2

4.1 Description of Model Ferry 2

4.2 Model Test Conditions 3

4.3 Discussion of Results 3

5.0 ITALY (MNF) 3

6.0 ITALY (CONFITARMA) 4

7.0 JAPAN 6

8.0 SPAIN 7

9.0 SCANDINAVIA 8

9.1 Description of Model Ferry... 8

10.0 CONCLUSION 10

11 .0 REFERENCES

Appendix A: SOLAS 90 Model Test Conditions

Appendix B: Bibliography

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LIST OF TABLES AND FIGURES

Tables United kingdom and Scandinavian Model Particulars 1

Italian MNF Research Model Particulars 2

Italian CONFITARMA Model Particulars 3

Japan Model Particulars 4

Spain Model Particulars 5

Scandinavian Model Particulars 6

Figures Results of Capsize Boundary Tests (Model 1), UK. and Scandinavia ... 1 Results of Capsize Boundary Tests (Model 2), UK. and Scandinavia ... 2 Description of Damage Cases, Italian MNF Research Model 3 Longitudinal View and Main Deck, Italian CONFITARMA Model 4 Overview of Japanese Ship Research Institute Model 5 Graph of GZ Curves With Water on Deck With GM=3.12m, Ship Research

Institute, Japan 6

Model Arrangement of Ferry, Spain 7

Dependence on Sea State with Significant Wave Height as the Independent

Variable, Spain

.."

8-10

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COMPARISONS OF MODEL EXPERIMENTS TO DETERMINE

j

SURVIVABILITY LIMITS AFTER DAMAGE ON ROLL-ON ROLL-OFF

- PASSENGER FERRIES

; ! 1.0 Summary

The following report summarizes different model experiments performed by ; i countries around the world. The tests were performed in 1995 to observe stability

^

and survivability of ro-ro ferries after damage has occurred. The results of the

tests are useful for the International Maritime Organization, as they are eager to set new regulations to ensure the safety of passengers and crew.

Descriptions of models built by countries who participated in the model testing i i are outlined below. The model test conditions each country used are described in

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Appendix A. Comparisons are made between the results of the tests carried out

by the different institutions and a brief summary outlining the models'

, performances in significant waveheights is presented at the end of the report. 2.0 Introduction

M

In the past year, extensive research has been carried out concerning survivability

limits after damage on roll-on roll-off passenger ferries. After recent tragic accidents of ferries capsizing, the International Maritime Organization became

M

interested in finding out the causes of these accidents and how they might be

avoided in the future. Many tests and experiments have been executed using model ships in several countries around the world.

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The International Maritime Organization selected a group of thirty or more Ocean

Engineering Researchers and Naval Architects to form a Panel of Experts. This

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panel was created to propose new regulations to amend SOLAS 90 (Safety of

- Life at Sea). The new regulations must ensure adequate stability and

survivability and need to be thoroughly reviewed and tested as the lives of many

passengers and crew are at risk.

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Countries around the world, such as the United Kingdom, Norway, Sweden, \ Finland, Denmark, Japan, Italy and Spain received the proposed amendments

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from the Panel of Experts. Participants built models and performed test and

evaluation and analysis followed. This new information could then serve as a j guide in formulating the new regulations based on all the models1 performances

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in the SOLAS 90 conditions.

It should be mentioned as well that Canada did participate in the model testing.

U The Institute for Marine Dynamics in Canada performed tests on a model ro-ro

ferry and obtained experimental data to study patterns and performance after damage had occurred. The data obtained from the tests was considered by the

J Panel of Experts due to the interest in freeing ports on ro-ro ferries. The model

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not be applied in determining the SOLAS 90 regulations. Further information is

available in Reference [1]. 3.0 Model Descriptions

Models built should have represented the actual ship for the internal and external

arrangements, including the damage spaces. The length between perpendiculars was to be at least three meters and the hull of the model was to be thin enough

in areas where this feature had influence on the results. Scaling of the radius of

gyration in roll and pitch motions and wave heights should have been

represented properly. Draft, trim, heel and center of gravity should have

represented the worst damage case. Watertight bulkheads and other main design features should have been modeled to represent the actual ship.

The model test conditions were proposed by the Panel of Experts and are

outlined in Appendix A.

By evaluating certain characteristics of the tests, such as amount of water on deck, number of times capsizing occurred, stability control, and amount of

freeboard, the research institutes that performed the tests were able to submit

this data collected to the Panel of Experts. They will distinguish new regulations

based on the models and the test results. 4.0 United Kingdom and Scandinavia 4.1 Description of Model Ferry

Marine Safety Agency and Joint North West R & D Project [Reference 2], built two ferry models used for testing stability and survivability after damage. The first model represented a centrecasing design and was also tested as sidecasing and open deck configurations. The second model had a different hull configuration, and possessed improved stability characteristics and freeboard in the damaged condition. It was tested as centrecasing and sidecasing designs, as well as having an open deck configuration. The various ship parameters are given in

table 1.

Table 1: Principal particulars (Marine Safety) Scale ratio Ship length (Lpp) Breadth (B) Draught (T) Displacement Freeboards (m) Shipi 1:42.033 131 m 26.0 m 6.1 m 12200t 0.2/0.6/1.1 Ship 2 1:34.667 130 m 25.5 m 5.75 m 11738t 0.5/1.0/1.9

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LM-1996-01

4.2 Model Test Conditions

The model was free to drift in beam seas and tested in periods of 30 to 60

minutes in equivalent scale time. The midship, forward and aft damage situations were tested in long crested waves, having heights ranging from 1.0 to 7.0

meters. The water on deck and vessel motions in six degrees of freedom were measured and recorded. Capsizing boundaries were also investigated by testing intermediate wave heights.

4.3 Discussion of Results

The results of the tests performed on the model used by Marine Safety Agency and Joint North West R & D Project agreed relatively well with the rule proposal. The amount of water on deck (approximately 1000 tonnes at 530 seconds) related to the allowable amount proposed by the regulations. Researchers

concluded that by entering curves at the GM value corresponding to the SOLAS

90 requirements, the limiting wave height for vessels with residual freeboards in the range 0.2 and 0.6 m after damage is 1.0 -1.5 m, thus confirming the Panel of

Experts1 proposal that the SOLAS 90 standard is adequate in significant wave heights up to 1.5 m. The results of the capsize boundary test for the first model tested are shown in figure 1.

The Marine Safety Agency also concluded that sidecasing vessels have enhanced survivability in waves compared with centrecasing vessels. The capsize boundary tests for the second model tested are shown in figure 2. Data collected proves that forward damage results in less water ingress, allowing the vessel to survive in more severe seas. Also, capsize limits were not very

sensitive to the size of the damage opening. 5.0 Italy (MNF)

5.1 Description of Model Ferry

A model built in Italy by MNF Research [Reference 3], had several characteristics that are important to mention. The ship model was characterized by one

compartment subdivision, along with main transversal watertight bulkheads at seven locations on the main ro-ro deck. Below the main ro-ro deck, there were six partial transverse watertight bulkheads. Damage was located across two wing tanks on each side of the model below the bulkhead deck and four double

bottoms. The residual freeboard was 0.98 meters and the GZ-area was 0.0418

meters radians in worst damage case. The various ship parameters are given in

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Table 2: Principal particulars (MNF) Draft fore Draft Ad Displacement Displacement: flooded VCG LCG Actual Ship 8.2 m 6.1 m 200091 220831

11.384 m from base line 74.848 from Aft PP

I I

At MNF Research, tests were performed on the model in various sea states. The model was tested in two trim conditions: the first was at a normal trim in full load condition, worst damage case, and the second was at an even keel, same full load displacement, worst damage case. The ship model motions were recorded and analyzed while the ship model was drifting freely, facing the waves. Twenty probes were installed on the main ro-ro deck to record the level of water

accumulated. Also, different mean values of accumulated water heights obtained from the post analysis of probe signals were considered.

In all tested conditions, the ship model used by MNF research, showed good seakeeping performance. The speeds and accelerations of pitch and roll motions were at low values. By increasing the damaged side residual freeboard, water could reach the opposite side of the model due to the absence of obstructions on the deck. Residual freeboard increased from 0.5 m to 0.72 m due to heeling during the trial.

6.0 Italy (CONFITARMA)

Another Italian research company called CONFITARMA (Confederazione Italiana Armatori) built a model to test stability and survivability after damage [Reference 4]. The model did not contain any subdivisions on the ro-ro main deck. Two compartments below the main deck were flooded through an opening on the starboard side representing the worst damage case. The side tank and double bottom were also damaged. The port side tank was flooded through the double bottom whereas the tank above the double bottom was intact. The model was built using wood with fiber glass reinforced plastic or aluminum plates placed in compartments to keep a thin shell plating. The model was fitted with two

propellers and shafts, rudders and bilge keels. The parameters of the model and ship are given in table 3. Figure 4 shows the longitudinal view and the main deck

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LM-1996-01

Table 3: Principal particulars (CONFITARMA) Scale ratio

Ship length (Lpp) Breadth overall Breadth waterline Depth main deck Draught

Block Coefficient Main deck length Main deck area

Ship 1:30 166 m 27.0 m 25.8 m 8.75 m 6.50 m 0.58 149.5 m

3500 m 2

Model 1:30 5.53 m 0.9 m 0.86 m 0.29 m 0.22 m 0.019 4.983 m

116.7 m2

The model used by CONFITARMA was exposed to long crested, irregular seas and freely drifted approximately parallel to the wave crests with the damage on

the starboard side facing the waves. In order for the waves to become constant in height and speed, it was necessary to wait a few seconds until the sea state

was completely uniform before measurements could be taken. The model ran over a time corresponding to half an hour in full scale time (time scale 1:5.477). The sea states used were defined by the significant wave heights having a range

from 1.5 m to 4.0 m and their modal period having a range from 4.90 s to 8.00 s.

The results obtained by CONFITARMA in Italy, were very positive and agreed relatively well with the rule proposal. Several observations that follow are worth

noting. The rolling motion of the model was not symmetrical about zero due to

water accumulation on the ro-ro main deck opposite the damage hole. For lateral acceleration, again, the rolling motion was not symmetrical due to the gravity component when heeling occurs and to the relative motion in front of the opening. The residual stability due to SOLAS 90 and forward trim stopped the

accumulation of a larger amount of water on the ro-ro main deck.

Reducing the GM to 1.2 m with the ship trimmed on even keel in the damaged condition led to higher freeboard and metacentric height due to the wider

waterline at the stern. This reduction in GM had no significant effect on behavior because the freeboard became so high that only a small quantity of water

appeared. The buoyancy loss in the forebody caused a forward trim, which prevented the accumulation of a larger amount of water on the ro-ro main deck. Due to the stability, the small amount of water did not cause any significant

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7.0 Japan

Model tests were carried out by the Ship Research Institute of Japan [Reference 5]. The model tested had a sidecasing configuration, without any barriers or

centrecasing on the ro-ro main deck. The model was tested with a two

compartment damage condition, and a damaged freeboard of 40 centimeters at the opening. The parameters of the model and ship are given in table 4. An

overview of the model is shown in figure 5. Table 4: Principal particulars (Japan) Scale ratio Ship length (Lpp) Breadth B Depth D Draft d Freeboard f

Height of ro-ro deck Displacement W

Center gravity above keel KG

Metacentric height gm Ship 1:23.5 101.0m 16.0 m 5.7 m 4.37 (5.22)m 1.17(0.33)m 4.84 m 3821.151 5.87 m 1.62 m Model 1:23.5 4.3 m 0.681 m 0.236 m 0.186 (0.22)m 0.05 (0.014)m 0.206 m 272.69 kg 0.25 m 0.069 m

* Numbers in brackets represent after damage conditions

The model used by the Ship Research Institute of Japan, with a certain GM value and freeboard, was placed with the damage opening facing irregular waves 4 meters in height for 30 minutes in actual ship time. The amounts of water accumulated on the ro-ro deck and heeling patterns of the model were measured. Tests were repeated with different wave trains and GM damaged values. Further tests were completed using the same model with centrecasing present. No transverse barriers were present on the ro-ro deck.

The Ship Research Institute of Japan made a significant observation that the water depth criterion of 50 centimeters was too much for the model and did not reflect the physics of capsizing. By observation, the largest GM damaged

condition did not meet the requirements by calculation of 50 centimeters of water on the deck specified in the regulations. Figure 6 shows the GZ curves for a damaged model with a metacentric height of 3.12 meters and various amounts of

water on the ro-ro main deck. The curves clearly show how 50 centimeters of water on the ro-ro main deck does not meet adequate standards for survivability.

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By performing other tests, the amount of water for the least freeboard condition and the high sea condition of 4 m wave height should be 12 centimeters.

The Institute of Japan also concluded that their model, along with many other ro-ro ships complying with the regulation specified, will be able to demonstrate their survivability by model tests carried out, even if the calculation with the water on the ro-ro deck may indicate otherwise. Ro-ro ships capsize because of

insufficient damage stability and not of accumulated water on the ro-ro deck. Researchers of Japan concluded that it is important to have a large enough

stability margin to provide safety of ro-ro ferries. 8.0 Spain

In Spain, CEHIPAR (Canal de Experiencias Hidrodinamicas de El Pardo), built a model based on a Spanish ferry vessel [Reference 6]. It was made using wood

and had a rudder and bilge keel reproduced from the actual ship. The model was

loaded to achieve different residual freeboards with an upright and even keel after damage conditions. To support varying ballast weights, the model contained four holds and reserve buoyancy was placed on the upper deck to prevent the model from completely capsizing. A garage deck was reproduced at 8.1 meters over the baseline without any obstruction, casing or trunks. Damage was near amidships on the starboard side. A vertical extension was produced from the bottom to the upper deck that produced flooding of the main engine room and the auxiliary machinery room. The double bottom was not flooded. The parameters of the model and ship are given in table 5. A model arrangement is shown in

figure 7.

Table 5: Principal particulars (Spain) Scale ratio

Ship length overall Ship length (Lpp) Maximum breadth Moulded draft

Depth to garage deck Garage deck area

Ship 1:24 140.8 125.0 m 22.0 m 6.0 m 8.1 m

2300 m2

Model 1:24 5.867 m 5.208 m 0.917 m 0.250 m 0.338 m

3.993 m2

CEHIPAR's model based on the Spanish ferry was tested in nine different

loading conditions to study the influence of residual freeboard and stability in the ship's behavior after damage. The loading conditions were combinations of three residual freeboards at the damage and three effective metacentric heights after damage. Loading conditions were such that the ship would stay upright at an

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even keel after damage. For each loading condition, the model was subjected to irregular, long crested seas corresponding to the wave spectra with three

different significant wave heights. The model was parallel to the wave crests and the damaged side (starboard) was facing the incoming waves. The model was free to drift and could move in six degrees of freedom. The data acquisition

started after the wave pattern was fully developed.

Results obtained from experiments performed on a model ship in Spain agreed relatively well with the regulations proposed. In all experimental cases, with symmetrical flooding, the model tended to heel to the side opposite the incoming waves thus increasing the real freeboard at the damaged side. The heeling increased progressively until the freeboard at the damage was large enough to avoid further ingress of water. The amount of water accumulated on the garage deck for the waves of 2.75 and 4 meters significant wave height was very similar to that given by the formula of the Panel of Experts. Figures 8 to 10 illustrate the dependence on sea state where significant wave height is the independent variable. With water on deck, the model, with a GM as required by SOLAS 90 or higher, was able to withstand waves up to 4 meters in height with no capsizing. CEHIPAR in Spain did observe that the theoretical calculations of static stability did not take into account any contribution of the hull forms over the garage deck. Researchers thought the calculations of the hull forms should be included

because they seem to have some contribution to the righting arm due to dynamic effects.

9.0 Scandinavia

Tests performed by several countries including Denmark, Finland, Norway and Sweden, used a model to detect the required heights of transverse bulkheads on a ro-ro main deck [Reference 7]. Two configurations of the model were tested; a centrecasing design and a sidecasing design based upon the same basic hull form and subdivision configuration. Two sets of transverse bulkheads were

present, subdividing the vehicle deck into three almost equal sections. The model also contained a hanging deck 45 meters long and 4.5 meters wide. Vessel

parameters are given in table 6.

Table 6: Principal particulars (Denmark, Finland, Norway, Sweden) Ship length overall

Breadth Draft Intact GM: centrecasing Intact GM: sidecasing Ship 130 m 25.5 m 5.75 m 2.5 m 2,1 m

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The tested configuration built by several countries including Denmark, Finland,

Norway and Sweden, was presented against significant wave height in the range ! of 2.5 m to 5.0 m with a corresponding range of modal periods from 6.3 s to 9.0 '-"' s. Tests were performed to investigate the required height of transverse

bulkheads, the effects of lowering hanging decks down onto partial height transverse bulkheads, the effects of openings in centrecasing, the effects of — vessel heading and the effects of sidecasing height.

i J

Using centrecasing and sidecasing configurations, the tests performed by I Denmark, Finland, Norway and Sweden obtained some positive results in

^

relation to detecting adequate heights for transverse bulkheads on ro-ro main

decks. By performing several tests, the flaps on top of partial height bulkheads had a positive effect. By placing openings in the centrecasing, a positive effect in

J

prolonging the time before capsizing was significantly noticed. Changing the

heading by 30 degrees to 60 degrees reduced water ingress and water sloshing. Half height transverse bulkheads were more effective and the vessel survived in

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significantly higher sea states. Increasing the damaged freeboard from 0 to 0.5

meters will have the positive effect of providing a better safety margin against capsize and increasing the GM will also give a better safety margin against

M capsize.

For sidecasing configurations, the researchers found that the sidecasing should M extend at least 2 decks up from the main vehicle deck. Hanging decks next to

^

sidecasing on top of 2.3 meter high transverse bulkheads will have a positive

effect by reducing overflow to adjacent compartments.

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The results of the testing done by these four countries had some negative effects

as well. When testing partial height bulkheads, researchers discovered that water | tends to overflow into the adjacent compartments due to sloshing effects. With

^ partial height transverse bulkheads, water tends to overflow in the comer

between casing and bulkhead. If this problem is not taken care of by pumps, the model capsizes.

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10.0 Conclusion

Safety and survivability are the most important factors while designing and fabricating ro-ro passenger ferry vessels. Research institutes that built and used models according to the proposed SOLAS 90 regulations have found that those regulations set are reliable and will guarantee the safety of ferry vessels after damage has occurred.

Table 7 illustrates the various maximum significant waveheights each model survived in SOLAS 90 conditions. The difference in results between the United Kingdom, Denmark, Sweden, Finland, and Norway and the rest of the group is most likely due to the actual physical shape of the model built for the testing and not due to the SOLAS 90 regulations followed. It is clearly shown that the

majority of the models survived waveheights of up to 4 meters and do provide safety by following the SOLAS 90 regulations. Perhaps further research and more experimental work are needed to determine the most feasible and safe

ferry design.

TABLE 7. Maximum Significant Waveheights Survived

COUNTRY

United Kingdom, Denmark,

Sweden, Finland, Norway

Italy (MNF)

Italy (CONFITARMA)

Japan

Spain

Scandinavia

Maximum waveheight survived in SOLAS 90 conditions Hs, m 1.0-1.5 m 4.0 m 4.0 m 4.0 m 4.0 m

-The analysis of the results of the many tests performed on models used all over the world will have significant importance to the design and manufacture of roll-on roll-off ferries in the future. The experimental data obtainedtrom the model tests will enable naval architects and engineers to improve the quality of ro-ro passenger ferries, increasing their survivability after damage has occurred.

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11.0 References

1. D. Molyneux and D. Cumming, "A Model Experiment Technique for Predicting

the Capsizing of Damaged Ro-Ro Ferries", Institute for Marine Dynamics, NRC,

Canada, 1995.

2. "Consideration and Adoption of Amendments to the International Convention for the Safety of Life at Sea, 1974: Results of Model Tests Carried out by Marine

Safety Agency (UK) and Joint North West European R & D Project", submitted by Denmark, Finland, Norway, Sweden and the United Kingdom, International

Maritime Organization, November 6,1995.

3. G. Mezzani, M. Nattero, C. Falcone, "Memorandum: Italian Research on

Ro-Ro Passenger Ship", Studio Associato Di Ingegneria Navale, MNF, August 1995. 4. P. Blume, "Survivability Tests for a Damaged Ro-Ro Passenger Vessel", Hamburg Ship Model Basin, Confederazione Italiana Armatori (CONFITARMA), Rome, 1995.

5. "Intersessional Working Group on Ro-Ro Ferry Safety: Consideration of the proposed draft SOLAS amendments and related matters", submitted by Japan, International Maritime Organization, 1st session, October 5,1995.

6. "Consideration and Adoption of Amendments to the International Convention

for the Safety of Life at Sea, 1974: Seakeeping Tests of a Damaged Ferry

Vessel", submitted by Spain, Canal de Experiencias Hidrodinamicas de El Pardo,

International Maritime Organization, November 14,1995.

7. "Consideration of the Proposed Draft SOLAS Amendments and Related Matters: Technical Issues Under Draft SOLAS regulations 11-1/8 and 8-2",

required height of transverse bulkheads on the ro-ro deck, based upon model

tests performed under the project "Safety of Passenger/Ro-Ro Vessels",

submitted by Denmark, Finland, Norway and Sweden, International Maritime

Organization, October 6,1995.

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2 3 GMI SOAS90GM Freeboard « 0.6nt GM< SOLAS90GM Freeboard c 1.1m SOLASdOGM CM!

Figure 1

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Freeboard * 0.5m o Capsize O No Capsize • Capsize Boundary! OMi _SOAS90GM Freeboard =1.0m 7 6 5

"4

3 2 1 ;.- -.-• •••—

^^%^^

'vi?:* . '■•'. • ' a .. ■•-•;...•' • • • • "^..S~ '. ( " •'•• ' I a -Capsize t No Capsee ! Capsize Boundary J 1 -2 SOLAS90GM GMI Freeboard «1.5m O GMI

Figure 2

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iz: c r::;.: i czz DAMAGE 12 DAMAGE 11 DAMAGE 10 DAMAGE7 WORSTCOND. DAMAGES OAMACgT* DAMAGE3 "DAMAGE2

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c c: t:;::: [.:::: r:: t::::. r: c i;:;: c::; t:;: c:: rz: t:

8.20 m

flooded spaces below main deck opening

AP

I

Pos. 1 Pos. 2 flooded spaces below main deck

prepared for a bulkhead oft the ro-ro deck

58.57 m -

-I

■ 98.31m 104.94 m

130.28 m distance from Aft Perpendicular

138.68 m

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! Ro-Rojdeck Camera for inside view of deck Center casing (Removable)

Figures

V"5 10 15 20 25 30 35 40 45 5) -02 -0.4 -0.6 -0.8 -1 A 2 •••x»10cm -•-• x=20cm -••- )F30cm x=50cm Figure 6

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LJ

2

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Significant wave heigfit (m)

Mean list In the lasts

minutes - *- GMsSOUS Fb=0.81 • «• GMSSOLAS40.4 fb=0.81 • ^- Gli«S0tAS*&8 fb«0^1 -M-GMeSOLAS Fb»1.15 -»~GMcSOLAS40^ fb»1.15 —♦—GMaSOLAS+14) fb«2.00

Figure 8

DAMAGED FERRY TESTS

Maximum rod angle

2 2.5 3

Significant wave height (m)

—H— GIfeSOUS Ftei.15 —«—GM«SOLAS*4.5 —♦—GfcfeSOLAS+1.0 --+- GM=SOLAS+0.5 fte&OO GIUUSOLAS+1.0 fb=2.00

Figure 9

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DAMAGED FERj?Y TESTS

Mean water level In garager In the last 5 minutes

GM=SOLAS FbsO.81 GMaSOLAS+0.4 fbsO.81 GM=SOLAS+0.8 (b=0.81 GMaSOLAS Fb=1.15 GM=SOLAS+0.5 (bai.15 GM=SOLAS+1.0 (b=1.15 GM=SOLAS+0.5 fb=2.00 GM=SOLAS+1.0 (b=2.00 2 2.5■:' ■ 3

Significant wave1 height (m)

Figure 10

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| i

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APPENDIX A

SOLAS 90 MODEL TESTING CONDITIONS

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ANNEX

PageS

Appendix

DRAFT MODEL TEST METHOD

1 Objectives

In the tests provided for in paragraph 1.4 ofthe stability requirements pertaining to the agreement,

the ship should prove capability to withstand a seaway defined in paragraph 3 hereunder in the worst

damage case scenario.

2 Ship model

2.1 The model should copy the actual ship for both outer configuration and internal arrangement -in particular ofall damage spaces, havirtg an effect on the process of flood-ing and shipp-ing of water. The damage should represent the worst damage case defined for compliance with 2.3.2 of regulation H-l/8 (SOLAS 90). An additional test is required at a level keel midship damage, if the worst damage location according to SOLAS 90 is outside the range ± 10 % Lpp from the midship. This additional test is only

required when the ro-ro spaces are assumed to be damaged. 2.2 The model should comply with the following:

.1 length between perpendiculars is to be at least 3 m;

.2 hull is to be thin enough in areas where this feature has influence on the results;

.3 characteristics of motion should be modelled properly to the actual ship, paying

particular attention to scaling of radii of gyration in roll and pitch motions. Draft, trim,

heel and centre of gravity should represent the worst damage case;

.4 main design features such as watertight bulkheads, air escapes etc., above and below the bulkhead deck that can result in asymmetric flooding should be modelled properly as far as practicable to represent the real situation;

.5 the sh^e of the damage opening shall be as follows:

. 1 rectangular side profile with a width according to SOLAS regulation II-1/8.4.1 and unlimited vertical extent;

.2 . isosceles triangular profile in the horizontal plane with a height equal to B/5 according to SOLAS regulation IM/8.4.2.

3 Procedure for experiments

3.1 The model should be subjected to »long crested irregular seaway defined by the JONSWAP spectrum with a significant wave height Hs, defined in subparagraph 1.3 of the stability requirements and

having peak enhancement factor y and peak period Tp as follows:

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.1

Tp = 4y/Hs

with y = 3.3; and

.2 Tp equal to the roll resonant period for the damaged vessel without water on deck at the

specified loading condition but not higher than 6^/Hs and with y = 1.0.

3.2 The model should be free to drift and placed in beam seas (90° heading) with the damage hole facing the oncoming waves. The model should not be restrained in a manner to resist capsize. If the vessel is upright in flooded condition, 1° ofheel towards the damage should be given.

3.3 At least 5 (five) experiments for each peak period should be carried out. The test period for each run shall be of a duration such that a stationary state has been reached but should be run for not less than 30 min in full-scale time. A different wave realization train should be used for each test.

3.4 Ifnone ofthe experiments result in final inclination towards the damage, the experiments should

be repeated with 5 runs at eafch ofthe two specified wave conditions or, alternatively, the model should

be given an additional 1° angle of heel towards the damage and the experiment repeated with 2 runs at each of the*fwo specified waye conditions. The purpose of these additional experiments is to4 demonstrate, in the best possible way, survival capability against capsize in both directions. *

"• ■ • - . • •

3.5 The tests are to be carried out for the following damage cases:

. 1 the worst damage case with regard to the area under the GZ curve according to SOLAS;

and .' - *

.2 the worst midship damage case with regard to residual freeboard in the midship area if

required by.2.4. \ '

-4 Survival criteria . " .

4.1 The ship should be considered as surviving if a stationary state is reached for the successive test

nms as required in 3.3 but s^^^

:

*

■ * • ■-. •■■•..«.-. ■■■'••.■"■-''■ ., •..,■ .- '■

4.2 Angles of roll of more/than 30° against the vertical axis, occurring more frequently than in 20% of the rolling cycles or steady heel greater than 20° should be taken as capsizing events even if a stationary state is reached.

5 Test approval

5.1 It is the responsibility of the Administration to approve the model test programme in advance. It should also be bonr in mind that lesser damages may provide a worst case scenario. §

5.2 Test should be documented by means of a report and a video or other visual record containing all relevant information of the vessel and test results. A copy of the video and report should be submitted

to the Organization, together with the Administrations acceptance of the test.

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L

appendix b

bibliography

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the Capsizing of Damaged Ro-Ro Ferries", National Research Council of

Canada, Institute for Marine Dynamics, 1995.

2. "Consideration and Adoption of Amendments to the International Convention for the Safety of Life at Sea, 1974: Results of Model Tests Carried out by Marine Safety Agency (UK) and Joint North West European R & D Project", submitted by Denmark, Finland, Norway, Sweden and the United Kingdom, International

Maritime Organization, November 6,1995.

3. G. Mezzani, M. Nattero, C. Falcone, "Memorandum: Italian Research on Ro-Ro Passenger Ship", Studio Associate Di Ingegneria Navale, MNF, August 1995.

4. P. Blume, "Survivability Tests for a Damaged Ro-Ro Passenger Vessel", Hamburg Ship Model Basin, Confederazione Italiana Armatori (CONFITARMA),

Rome, 1995.

5. "Intersessional Working Group on Ro-Ro Ferry Safety: Consideration of the proposed draft SOLAS amendments and related matters", submitted by Japan, International Maritime Organization, 1st session, October 5,1995.

6. "Consideration and Adoption of Amendments to the International Convention for the Safety of Life at Sea, 1974: Seakeeping Tests of a Damaged Ferry

Vessel", submitted by Spain, Canal de Experiencias Hidrodinamicas de El Pardo, International Maritime Organization, November 14,1995.

7. "Consideration of the Proposed Draft SOLAS Amendments and Related Matters: Technical Issues Under Draft SOLAS regulations 11-1/8 and 8-2", required height of transverse bulkheads on the ro-ro deck, based upon model tests performed under the project "Safety of Passenger/Ro-Ro Vessels", submitted by Denmark, Finland, Norway and Sweden, International Maritime Organization, October 6,1995.

8. S. Murashige, "Tests of a Damaged Ro-Ro Ferry in Waves", Ship Research

Institute, Ministry of Transport, Japan, October 24,1995.

9. "Draft Model Test Method\ Safety of Life at Sea Conference, ANNEX,

appendix pp. 5-6.

10.1. Watanabe, "Interrelation Between Three Proposals", Ship Research Institute, Ministry of Transport, Japan.

11. "Full Text of the Report of the Sub-Group on Stability Requirements", Safety

of Life at Sea Conference 3/12, ANNEX 2.

12. K. Rawson, "Ro-ro Ships and IMO: A RINA Comment", The Naval Architect.

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13. D. Molyneux, RO-RO Ferry Passenger Vessel Capsize Investigation:

Physical Model Experiments. Phase 1. National Research Council of Canada,

Institute for Marine Dynamics, report TR-1994-04, St. John's, Newfoundland,

1994.

14. J.S. Pawlowski and D. Molyneux, Analysis of Experiments on RO-RO Damage Stability: Part 1. National Research Council of Canada, Institute for Marine Dynamics, St. John's, Newfoundland, October 5,1994.