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Trade News: Thordon contract to retrofit tailshaft bearings on 32 tugs

Focus on Thordon Tailshaft Bearings

Africa Ports & Ships

Thordon Bearings has secured a significant contract to convert the rubber tailshaft bearings across an entire fleet of Panama-operating tugs, pilot vessels, and workboats to water-lubricated polymer bearings.

The agreement with the unnamed operator follows the successful retrofitting of Thordon’s SXL tailshaft bearings to twelve of its twin-screw tugs last year during scheduled dry dockings.

The remaining 32 vessels will now be converted in batches at planned maintenance intervals over the next four years.

For the first batch of retrofit conversions, Thordon will supply a total of 62 bearings machined to fit shaft diameters ranging from 63.5mm to 101mm (2.5in to 4.5in). However, the scope of supply also includes Thordon’s ThorPlas-Blue bearings for tiller arms and jockey bars and SXL rudder bearings, both of which operate without the use of grease.

Egnard Bernal, Thordon Bearings’ Business Development Manager, Latin America, explained: “We have worked with this operator since 2020 when we resolved problems with the rubber tailshaft bearings on one of its Spanish-built pilot vessels.

“Following that initial success we have retrofitted one vessel after another but have now received a stock order for the entire fleet. All rubber tailshaft bearings will be replaced with SXL at scheduled dry dockings over the next few years. This is a significant order for Thordon Bearings,” he said.

Commenting on the reason behind the fleet-wide retrofit, Yves Silva, Regional Manager – LATAM, said: “This owner operates a zero-pollution policy, so we are moving very quickly to install a wide range of environmentally friendly solutions. The company wants all of its vessels to have 100% green operation and long lasting Thordon bearings are the most sustainable bearing options available.”

All of Thordon’s polymer bearings require neither grease nor oil for lubrication. Yet, while environmental protection was a major factor in the decision, so too was bearing longevity and reliability.

Interoceanic waterways tend to be very abrasive environments, which are not ideal for bronze-backed rubber bearings. The bronze outer shell and the steel housing are prone to galvanic corrosion, resulting in non-budgeted maintenance costs and drydockings.

“That this owner is planning to ‘Thordonize’ its entire fleet is testament to the reliability, long wear life and robust performance of our bearing technology,” Silva added. “Our bearings deliver on value, performance, and complete elimination of oil/grease pollution for both newbuild vessels and conversions.”

Added 23 May 2024

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In Conversation: Rogue waves in the ocean are much more common than anyone suspected, says new study

SA Agulhas passing the Bluff at Durban. It was from this ship that some of the research into rogue waves was conducted. Picture by Trevor Jones

Alessandro Toffoli, The University of Melbourne

We used three-dimensional imaging of ocean waves to capture freakish seas that produce a notorious phenomenon known as rogue waves. Our results are now published in Physical Review Letters*.

Rogue waves are giant colossi of the sea – twice as high as neighbouring waves – that appear seemingly out of nowhere. Stories of unimaginable mountains of water as tall as ten-storey buildings have populated maritime folklore and literature for centuries.

Recent technology has allowed scientists to spot rogue waves out at sea, making legend become reality. The first and most famous measurement was of the Draupner wave, a 25.6-metre monster recorded in the North Sea on January 1 1995.

Despite observations, we still don’t know how often rogue waves occur, or if we can predict them. A record of a rogue wave doesn’t include specific features that distinguish the sea around it, so we can’t make comparisons or predict the conditions needed.

Our team set sail on the South African icebreaker S.A. Agulhas-II to chase rogue waves across the Southern Ocean, where mighty winds shape Earth’s fiercest waves.

A blue coloured photo of the ocean surface with small white wave crests throughout.

Ocean surface during a storm somewhere in the Southern Ocean.
Alessandro Toffoli

What creates rogue waves?

In the random environment of ocean waves, several mechanisms give rise to rogue ones. One primary source involves the overlap of multiple waves at the same location and time. This results in concentrated energy, leading to tall waves.

Under consistent ocean conditions, rogue waves generated this way may occur once every two days at a set location. But the ocean is dynamic, so conditions are rarely consistent for long – making it less likely for rogue waves to occur. The overlap of waves may be minimal or non-existent even during prolonged and intense storms.

Numerical and laboratory studies suggest strong winds also contribute to the development of rogue waves, because they push harder on some already tall wave forms. But wind has seldom been considered in rogue wave analysis.

A simplified anatomy of ocean waves.
NOAA

Wind prompts ocean waves to grow progressively higher, longer and faster. During this stage, waves are “young” and hungry for wind input. When waves go faster than wind, they stop being accelerated by it and reach a “mature” stage of full development.

Through this process, the wind creates a chaotic situation where waves of different dimensions and directions coexist.

Our recent observations show that unique sea conditions with rogue waves can arise during the “young” stage – when waves are particularly responsive to the wind. This suggests wind parameters could be the missing link. However, there’s even more to consider.

Powerful waves amplify each other

Ocean waves are one of the most powerful natural forces on Earth and could become even more powerful in the future due to climate change. If the wave field possesses an extreme amount of energy – when waves are steep and most of them have a similar amplitude, length and direction – another mechanism can trigger the formation of rogue waves.

This mechanism involves an exchange of energy between waves that produces a “self-amplification”, where one wave grows disproportionately at the expense of its neighbours. Theoretically, studies show this could increase the likelihood of rogue waves ten-fold.

While self-amplification manifests as whitecaps – frothy, aerated crests of choppy waves – until now there has been no evidence it can make rogue waves more likely in the ocean.

Recent experiments suggest wind can make extreme events like rogue waves more common. But this aspect has not been thoroughly explored.

What did we find in the Southern Ocean?

We used a new three-dimensional imaging method for scanning the ocean surface throughout the expedition. It mimics human vision: closely located sensors record sequences of simultaneous images. Computer algorithms then match pairs of them to reconstruct the three-dimensional depths – the wavy surface.

As our ship passed through several storms, the sensors captured data during various phases of wave growth – from the early stages of young waves fuelled by the wind, to mature waves that aren’t influenced by it.

Our results show young waves display signs of self-amplification and an increased likelihood of rogue waves. We recorded waves twice as high as their neighbours once every six hours.

This mirrors what lab models have reported: sea conditions theoretically more prone to self-amplification would produce more rogue waves.

In contrast, mature seas don’t show an increased probability of rogue waves. We detected none under those conditions.

Our findings challenge previous thinking: that self-amplification doesn’t change the likelihood of rogue waves in the ocean. We have also shown that when developing tools for predicting rogue waves, we need to take wind into thorough consideration. After all, it’s a natural feature of the open sea.The Conversation

Alessandro Toffoli, Professor in Ocean Engineering, The University of Melbourne

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Added 16 April 2024

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INVITATION TO TENDER: Dock Pontoon – Pontoon Lifter

Dock Lifter SSR-1

Morska Stocznia Remontowa “Gryfia” S.A., Szczecin, Poland
announces a written invitation to tender for the sale of Set of units:
(Dock-pontoon PN – SSR –1, Dock-pontoon PN-SSR-3, Pontoon Lifter SSR-1)

Dock Pontoon SSR-1
Dock Pontoon SSR-3

The subject matter of the tender procedure is the ownership right to the Set of units (Dock-pontoon PN-SSR-1, Dock-pontoon PN-SSR-3, Pontoon Lifter SSR-1).

Technical description:

Dock-pontoon PN-SSR-1 – Built in 1966

– total length is 91,40 m
– external width 19,40 m
– internal width 17,00 m
– total height 9,30 m
– pontoon height 2,00 m
– load capacity 1460 tons

Dock-pontoon PN-SSR-3 built in 1967

– total length is 91.40 m
– external width 19.40 m
– internal width 16.00 m
– total height 9.20 m
– pontoon height 2.60 m
– load capacity 1460 tons

Pontoon Lifter SSR-1 built in 1966

– total length is 74.00 m
– external width 27.00 m
– internal width 21.00 m
– height of the pontoon 11.00 m
– carrying capacity 1700 tons

II. ASKING PRICE

Set of units – USD 1 100,000 (in words USD: one million one hundred thousand 00/100) net + applicable VAT.

which consists of:

Dock-pontoon PN-SSR-1 – 300 000 USD net + applicable VAT
Dock-pontoon PN-SSR-3 – 380 000 USD net + applicable VAT
Pontoon Lifter SSR-1 – 420 000 USD net + applicable VAT

III. BID DEPOSIT

USD 55,000.00 (in words USD: fifty-five thousand 00/100)

IV. DATE AND PLACE OF THE TENDER, SUBMISSION OF TENDERS

1. The tender will take place on 27.10.2023 at the registered office of Morska Stocznia Remontowa “Gryfia” S.A. in Szczecin, ul. Brdowska 12, 71-700 Szczecin, Poland.
2. The rules concerning the tender procedure and the qualification procedure of the tenderers, and the formal requirements concerning the tender are regulated by the “Tender Rules” available on the website of the Morska Stocznia Remontowa “Gryfia” S.A.:
https://www.msrgryfia.pl/en/przetargi

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Added 3 October 2023

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