EFFECT OF WATERTIGHT SUBDIVISION ON DAMAGE STABILITY OF RO-RO FERRIES

M Pawłowski; A Laskowski

doi:10.5750/ijme.v156ia2.921

EFFECT OF WATERTIGHT SUBDIVISION ON DAMAGE STABILITY OF RO-RO FERRIES

The International Journal of Maritime Engineering ◽

10.5750/ijme.v156ia2.921 ◽

2021 ◽

Vol 156 (A2) ◽

Author(s):

M Pawłowski ◽

A Laskowski

Keyword(s):

Critical Height ◽

Damage Stability

Effect of various subdivision arrangements of ro-ro vessels on damage stability is discussed. The arrangements included single and double sides both below and above the car deck, with and without a double buoyant car deck, and with or with- out a watertight tween deck below the car deck. This gave as many as 16 various arrangements for each compartment length. The double sides both above and below the car deck are of the same width b = 0.1B. The double bottom, when not flooded, worsens damage stability. The car deck and tween decks should be ‘openwork’, to be transparent for water and air. Oth- erwise, the ship can capsize at the very initial stages of flooding. Double sides and a double car deck together improve con- siderably damage stability, both in terms of maximum arm and range. A new characteristic was introduced, termed the critical deck height. Flooding a deck above the critical height leads to a rapid capsizing of the ship.

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Effect of Watertight Subdivision on Damage Stability of Ro-Ro Ferries

10.3940/rina.ijme.a2.2014.283 ◽

2014 ◽

Vol 156 (A2) ◽

Keyword(s):

Critical Height ◽

Damage Stability

Effect of various subdivision arrangements of ro-ro vessels on damage stability is discussed. The arrangements included single and double sides both below and above the car deck, with and without a double buoyant car deck, and with or without a watertight tween deck below the car deck. This gave as many as 16 various arrangements for each compartment length. The double sides both above and below the car deck are of the same width b = 0.1B. The double bottom, when not flooded, worsens damage stability. The car deck and tween decks should be openwork, to be transparent for water and air. Otherwise, the ship can capsize at the very initial stages of flooding. Double sides and a double car deck together improve considerably damage stability, both in terms of maximum arm and range. A new characteristic was introduced, termed the critical deck height. Flooding a deck above the critical height leads to a rapid capsizing of the ship.

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Conception and Evolution of the Probabilistic Methods for Ship Damage Stability and Flooding Risk Assessment

Journal of Marine Science and Engineering ◽

10.3390/jmse9060667 ◽

2021 ◽

Vol 9 (6) ◽

pp. 667

Author(s):

Dracos Vassalos ◽

M. P. Mujeeb-Ahmed

Keyword(s):

Risk Assessment ◽

Probabilistic Method ◽

Probabilistic Methods ◽

Full Description ◽

Safety Level ◽

Probability Of Survival ◽

Damage Stability ◽

Passenger Ships ◽

Flooding Hazards ◽

Flooding Risk

The paper provides a full description and explanation of the probabilistic method for ship damage stability assessment from its conception to date with focus on the probability of survival (s-factor), explaining pertinent assumptions and limitations and describing its evolution for specific application to passenger ships, using contemporary numerical and experimental tools and data. It also provides comparisons in results between statistical and direct approaches and makes recommendations on how these can be reconciled with better understanding of the implicit assumptions in the approach for use in ship design and operation. Evolution over the latter years to support pertinent regulatory developments relating to flooding risk (safety level) assessment as well as research in this direction with a focus on passenger ships, have created a new focus that combines all flooding hazards (collision, bottom and side groundings) to assess potential loss of life as a means of guiding further research and developments on damage stability for this ship type. The paper concludes by providing recommendations on the way forward for ship damage stability and flooding risk assessment.

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Variance reduction in Ueno's method and cylinder sampling for forest volume estimation

Canadian Journal of Forest Research ◽

10.1139/x95-193 ◽

1995 ◽

Vol 25 (11) ◽

pp. 1783-1794 ◽

Cited By ~ 3

Author(s):

Thomas B. Lynch

Keyword(s):

Computer Simulation ◽

Variance Reduction ◽

Volume Estimation ◽

Critical Height ◽

Volume Estimate ◽

Individual Tree ◽

Stand Volume ◽

Reduction Techniques ◽

Antithetic Variates ◽

Volume Equation

Three basic techniques are proposed for reducing the variance of the stand volume estimate provided by cylinder sampling and Ueno's method. Ueno's method is based on critical height sampling but does not require measurement of critical heights. Instead, a count of trees whose critical heights are less than randomly generated heights is used to estimate stand volume. Cylinder sampling selects sample trees for which randomly generated heights fall within cylinders formed by tree heights and point sampling plot sizes. The methods proposed here for variance reduction in cylinder sampling and Ueno's method are antithetic variates, importance sampling, and control variates. Cylinder sampling without variance reduction was the most efficient of 12 methods compared in computer simulation that used estimated measurement times. However, cylinder sampling requires knowledge of a combined variable individual tree volume equation. Of the three variance reduction techniques applied to Ueno's method, antithetic variates performed best in computer simulation.

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Identifying and Characterizing Important Trembling Aspen Competitors with Juvenile Lodgepole Pine in Three South-Central British Columbia Ecosystems

International Journal of Forestry Research ◽

10.1155/2012/573640 ◽

2012 ◽

Vol 2012 ◽

pp. 1-12

Author(s):

Teresa A. Newsome ◽

Jean L. Heineman ◽

Amanda F. Linnell Nemec

Keyword(s):

British Columbia ◽

Lodgepole Pine ◽

Geographic Range ◽

Regression Analyses ◽

Relative Height ◽

Trembling Aspen ◽

Ecosystem Productivity ◽

Height Ratio ◽

Critical Height ◽

South Central

Critical height ratios for predicting competition between trembling aspen and lodgepole pine were identified in six juvenile stands in three south-central British Columbia ecosystems. We used a series of regression analyses predicting pine stem diameter from the density of neighbouring aspen in successively shorter relative height classes to identify the aspen-pine height ratio that maximizedR2. Critical height ratios varied widely among sites when stands were 8–12 years old but, by age 14–19, had converged at 1.25–1.5. MaximumR2values at age 14–19 ranged from 13.4% to 69.8%, demonstrating that the importance of aspen competition varied widely across a relatively small geographic range. Logistic regression also indicated that the risk of poor pine vigour in the presence of aspen varied between sites. Generally, the degree of competition, risk to pine vigour, and size of individual aspen contributing to the models declined along a gradient of decreasing ecosystem productivity.

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Effect of Longitudinal Bulkheads on Damage Stability of Model RO/RO Ferries

Marine Technology and SNAME News ◽

10.5957/mt1.2003.40.1.20 ◽

2003 ◽

Vol 40 (01) ◽

pp. 20-24

Author(s):

Carl T. F. Ross ◽

Ioannis Mourtos ◽

George Papanikolaou

Keyword(s):

Second World War ◽

Motor Vehicles ◽

Scale Model ◽

Experimental Investigations ◽

Free Enterprise ◽

Modified Model ◽

Damage Stability ◽

History Of ◽

Transverse Damage ◽

Second World

The paper reports on experimental investigations which have been made on three model RO/RO ferries. One of these was based on a 1/100th scale model of the Herald of Free Enterprise ferry. The other models were modified versions of the Herald of Free Enterprise which were so modified that they did not decrease the efficient concept of the throughput of a conventional vessel. One modified model had nine longitudinal compartments, while another had six longitudinal compartments; these vessels should meet SOLAS90+50 regulations. The RO/RO ferry models with nine and six compartments had considerably better damage stability characteristics than the conventional model. The experiments were carried out on all models without the consideration of waves and wind. Small weights were placed on the model ferries, to represent motor vehicles, and water was added on the car deck. Measurements of the resulting heel angles were taken. All results were plotted on graphs and they were compared and discussed. The effect of cargo shift on the transverse damage stability of these vessels was found to be significant. The paper also contains a brief history of a few very important RO/RO ferry accidents that have taken place since the end of the Second World War.

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Preliminary Damage Assessment Process Using Decision Support System - Initial Damage Stability Assessment and Verification Based on Existing And Proposals for Future Damage Stability Regulation

10.3940/rina.ds.2015.11 ◽

2015 ◽

Author(s):

J Gullaksen ◽

Keyword(s):

Decision Support ◽

Decision Support System ◽

Support System ◽

Damage Assessment ◽

Assessment Process ◽

Stability Assessment ◽

Initial Damage ◽

Damage Stability

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A Review of the Ninth International Conference on the Stability of Ships and Ocean Vehicles (STAB 2006)

Marine Technology and SNAME News ◽

10.5957/mt1.2008.45.3.147 ◽

2008 ◽

Vol 45 (03) ◽

pp. 147-156

Author(s):

Marcelo A. S. Neves ◽

Vadim Belenky

Keyword(s):

Rio De Janeiro ◽

High Speed ◽

International Conference ◽

Intact Stability ◽

Damage Stability ◽

Operation Stability ◽

The Stability

The paper gives a brief review of the papers presented at the Ninth International Conference on Stability of Ships and Ocean Vehicles that was held on September 25 to 29, 2006 in Rio de Janeiro, Brazil. The review covers the following stability-related subjects: stability regulations, intact stability, wind and waves, damage stability, stability in operation, stability of high-speed craft, and offshore vehicles.

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Tumblehome Ships - From Greek Triremes to the Zumwalt

10.5957/smc-2021-016 ◽

2021 ◽

Author(s):

Robert Forrest Roddy

Keyword(s):

World War I ◽

World War ◽

Steam Power ◽

Loss Of Life ◽

Damage Stability ◽

The Us ◽

Us Navy ◽

Major Loss

After almost a century the US Navy has reintroduced tumblehome into the design of naval combatants. This paper discusses some of the reasons tumblehome was originally designed into ships and why it served it owners well for many centuries. The transition from sail to steam power a little over a century ago led to a variety of problems with the combatant ships designed with tumblehome where the lack of damage stability caused a major loss of life as these ships sank so quickly. During World War I ships designed with tumblehome fell out of favor and some of the ships were actually modified to remove the tumblehome from the design. These changes in the design of tumblehome ships are discussed in this paper.

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