Model Test and Full Scale Measurements of Whipping on Container Vessels in the North Atlantic

2009 ◽  
Author(s):  
Gaute Storhaug ◽  
Jan Mathisen ◽  
Svein Erling Heggelund
Keyword(s):  
Model Test ◽  
North Atlantic ◽  
Ship Design ◽  
Full Scale ◽  
Elastic Model ◽  
Container Ship ◽  
Hull Girder ◽  
The North ◽  
The North Atlantic ◽  
Wave Induced

Ships vibrate due to waves, and these wave induced vibrations can not easily be avoided by moderate changes to the hull lines. The waves may cause the whole hull girder to vibrate due to springing (resonance) and whipping (transient response), which increase the fatigue and extreme loading. Recently this has also become an industry concern. Modern hull monitoring systems in combination with model tests are the best tools to answer the key questions: How important is the wave induced vibrations, and does it have to be included in design? This paper addresses the effect of whipping on the extreme loading. Measurements have been carried out on two container vessels operating in the North Atlantic. An elastic model of the larger vessel has also been tested. Results are obtained at quarter lengths and amidships. From the measurements the increase due to whipping is considerable, even though the wave conditions are not extreme. The full scale measurements and model test show that IACS URS11 rule loads may be exceeded in less than extreme sea states, in particularly amidships and in the aft ship. The IACS UR S11 may need revision for container ship design. MAIB’s report based on the investigation of the MSC Napoli incident (vessel broke in two) also recommends increased requirements for container ship design and further research into the effect of whipping.

Assessment of Hull Monitoring Measurements for a Large Blunt Vessel

2013 ◽  
Author(s):  
Gaute Storhaug ◽  
Ole Jakob Hareide
Keyword(s):  
North Atlantic ◽  
Safety Margin ◽  
Bending Moment ◽  
Original Design ◽  
The North ◽  
Industry Standard ◽  
Design Life ◽  
Collapse Strength ◽  
The North Atlantic ◽  
Wave Induced

A large blunt vessel was designed for a longer target life than usual in world-wide trade. Due to experience with whipping and springing, special attention to these effects was also made during the design and approval in order to ensure satisfactory strength of the vessel. The vessel was consequently strengthened beyond the minimum industry standard, and it has now been operated for several years. The owner/operator who observed wave induced vibrations (whipping/springing) onboard, equipped the vessel with a hull monitoring system from a recognized supplier. After a few years of measurements, the data was sent to DNV for assessment of the effect of the vibrations and the consequence for the particular design. The data shows that the vessel has been trading in more demanding areas than assumed during design, but the environment is less severe than the North Atlantic. The measured fatigue life based on a stress concentration factor of 2.0 has been estimated to be well below the design life, so special attention to cracks need to be taken from now on if the trade remains the same in the future. No cracks have, however, been identified so far during inspection. The vessel has also experienced two severe storms. The maximum loading level has been higher than ever assessed by DNV before based on hull monitoring data of blunt vessels. The rule of thumb value of 20% increase on extreme loading for blunt vessels due to whipping has been exceeded. The wave bending moment according to IACS URS11 has also been exceeded without whipping. The ultimate collapse strength has been assessed and compared to the measured dynamic loading and allowable still water loading. When whipping is assumed fully effective to contribute to collapse, the safety margin is still above 1.0, but on the borderline of what is desirable. However, if the vessel had not been strengthened beyond the original design due to the concern of whipping and springing, the safety margin would have been below 1.0. This may be the first documentation of a vessel that has been saved from breaking in two due to addressing springing and whipping properly during design.

The Currents of the North Atlantic

1892 ◽  
Vol 34 (872supp) ◽  
pp. 13940-13941
Author(s):  
Richard Beynon
Keyword(s):  
North Atlantic ◽  
The North ◽  
The North Atlantic

NATO adaptation to current challenges and mechanisms of Ukraine’s cooperation with the North Atlantic Treaty Organization

2019 ◽  
pp. 73-81
Author(s):  
Oleh Poshedin
Keyword(s):  
North Atlantic ◽  
Task Force ◽  
Response Force ◽  
Cyber Attack ◽  
Adaptation Measures ◽  
Joint Force ◽  
Security Environment ◽  
The North ◽  
The North Atlantic ◽  
Area Of Influence

The purpose of the article is to describe the changes NATO undergoing in response to the challenges of our time. Today NATO, as a key element of European and Euro-Atlantic security, is adapting to changes in the modern security environment by increasing its readiness and ability to respond to any threat. Adaptation measures include the components required to ensure that the Alliance can fully address the security challenges it might face. Responsiveness NATO Response Force enhanced by developing force packages that are able to move rapidly and respond to potential challenges and threats. As part of it, was established a Very High Readiness Joint Task Force, a new Allied joint force that deploy within a few days to respond to challenges that arise, particularly at the periphery of NATO’s territory. NATO emphasizes, that cyber defence is part of NATO’s core task of collective defence. A decision as to when a cyber attack would lead to the invocation of Article 5 would be taken by the North Atlantic Council on a case-by-case basis. Cooperation with NATO already contributes to the implementation of national security and defense in state policy. At the same time, taking into account that all decision-making in NATO based on consensus, Ukraine’s membership in the Alliance quite vague perspective. In such circumstances, in Ukraine you often can hear the idea of announcement of a neutral status. It is worth reminding that non-aligned status did not save Ukraine from Russian aggression. Neutral status will not accomplish it either. All talks about neutrality and the impossibility of Ukraine joining NATO are nothing but manipulations, as well as recognition of the Ukrainian territory as Russian Federation area of influence (this country seeks to sabotage the Euro-Atlantic movement of Ukraine). Think about it, Moldova’s Neutrality is enshrined in the country’s Constitution since 1994. However, this did not help Moldova to restore its territorial integrity and to force Russia to withdraw its troops and armaments from Transnistria.

Traits structure copepod niches in the North Atlantic and Southern Ocean

2018 ◽  
Vol 601 ◽  
pp. 109-126 ◽  
Author(s):  
N McGinty ◽  
AD Barton ◽  
NR Record ◽  
ZV Finkel ◽  
AJ Irwin
Keyword(s):  
Southern Ocean ◽  
North Atlantic ◽  
The North ◽  
The North Atlantic
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