Technology Archives - QuantiServ

Propeller Shaft Line Work on New ULCS

21st November 2024

After we have in an earlier post looked at some recent two-stroke main engine crankshaft repair assignments that we have carried out on ships in operation, we now move the focus further towards the after end of the ship.

In this post we look at how we routinely support new building shipyards with shaft line alignment and machining work.

Read more about our recent two-stroke crankshaft work assignments

Shaft Line Work for VLCS in China: Recent Success Stories

At QuantiServ, we routinely perform essential alignment and machining work on behalf of shipyards in China on new vessels under construction. We do this for a wide range of vessels.

In this post we look at some of the very largest vessels that we work on, namely Very Large Container Ships (VLCS). These are vessels with a capacity to simultaneously carry up to 24’000 standard, 20-foot shipping containers. Typically, these ships are 400 meters long, about 62 meters wide and have a draught of about 16 meters when fully loaded.

These colossal vessels typically feature shaft lines that span between 80 to 100 meters in length, with shaft diameters ranging from 900 mm to over 1000 mm. These impressive dimensions are imperative due to the massive power of these ships’ main engines, which can reach up to 60,000 kW. This is equivalent to the power of 600 average-sized cars.¹

Case 1: Stern Tube Bearing Failure Recovery

In one notable project, we assisted a shipyard and shipowner after a stern tube bearing failure on a recently delivered VLCS. While underway, the ship’s stern tube bearing suddenly overheated, reaching temperatures of well over 200 ℃, leading to the complete destruction of the bearing bush. The sudden heat increase also led to cracks in the propeller shaft.

Obviously, this critical issue required prompt action to prevent extensive downtime. Our team efficiently assisted the shipyard to replace the bearing bushes and machined the shaft in-situ to remove the cracks in its surface. Our ability to machine the shaft in-situ eliminated the need to withdraw it, which would have been a time consuming and risky operation. This approach thus not only saved valuable time and therefore minimized operational losses. It also reduced the risk of anything going wrong during the delicate propeller and shaft removal and reinstallation work and ensured that the vessel could return to service swiftly.

After completion of our work, the shaft bearing temperature was recorded at just 32 ℃, no more than 13 ℃ Celsius above the surrounding sea water temperature, which is an excellent result!

Case 2: Construction Phase Alignment and Line-Boring

During the construction of another VLCS, our laser alignment checks revealed that the newly delivered and installed stern tube suffered from ovality and incorrect slope, posing a significant threat to the vessel’s long-term, safe performance. Once our team brought this information to the attention of the shipyard and proposed to line bore the stern tube, the shipyard, classification society and shipowner quickly agreed to our solution.

By employing precise in-situ line boring techniques, we corrected these issues, ensuring that the ship’s shaft line will perform optimally for many years to come. This intervention during the ship’s build phase highlights our commitment to quality and foresight.

Case 3: Long-standing cooperation

QuantiServ has long been a trusted partner for shipyards worldwide. We are often involved from the early stages of new-building projects, providing technical expertise and precision machining services. For example in China we have ongoing agreements with several major shipyards, whereby we carry out laser alignment and inspection services for entire series of vessels.

During the summer of 2024, we for example completed shaft alignment services for the sixth and final delivery in a series of large, LNG-fueled ships built for a major container shipping line. All six ships are now in operation and are performing very well.

Demonstrating Expertise Across the Industry

All three cases were undertaken in China on some of the worlds’ very largest and newest ships, that will be owned and operated by three of the world’s largest container shipping lines. They involved different shipyards and different classification societies. This diverse customer base underscores the broad acceptance and trust in QuantiServ’s expertise and know-how within the maritime industry.

The three ships highlighted in this post are all either LNG-powered or are able to operate on more than one fuel. As such, they contribute to the decarbonisation of the marine industry, which is a goal that QuantiServ very much supports. Furthermore, QuantiServ is proud to contribute to the reliability and efficiency of these magnificent vessels, ensuring they meet the highest standards of operational performance and safety.

A severely damaged stern tube bearing bush

Machining the outer circumference of a stern tube bearing bush

Delicate, ctitical work creates a lot of attention — Delicate, ctitical work always creates a lot of attention

Calibrating the outside diameter of the bearing bush at our workshop in Shanghai

Inspection of a large stern tube bush at the shipyard

¹ In 2018, the most recent year for which data are available, the average car in the European Union was fitted with an engine that was able to produce 98 kW of power.

“Manufactured Again”-Certification Renewed

20th June 2024

Our reconditioning centres in Dubai, Kruiningen, Singapore and Suzhou have been Manufactured Again certified since 2018. This prestigious mark represents the quality, value, and sustainability of our reconditioning (remanufacturing) processes and has just been renewed for another year.

Let’s delve into how this renewal benefits both our customers and our commitment to sustainability:

Quality Assurance: The Manufactured Again Certification ensures that our reconditioned products meet rigorous quality standards. By adhering to stringent processes and standards, we guarantee consistent excellence in our reconditioned goods.
Value Proposition: Reconditioned products offer exceptional value. They combine like-new quality with reduced production costs, resulting in better prices for our customers. By choosing our certified products, customers make an economically savvy choice without compromising on quality.
Environmental Impact: Sustainability lies at the heart of our journey. Reconditioning conserves embodied energy and reduces waste. For instance, reconditioning one large piston consumes about six times less resources than producing a new one! Our commitment to reconditioning and sustainability aligns with global efforts to reduce environmental impact.
Customer-Centric Approach: By holding the Manufactured Again Certification, we demonstrate our dedication to customer satisfaction. Customers can trust that our reconditioned components are not only eco-friendly but also reliable and high-performing.

In summary, our renewed certification reinforces QuantiServ’s position as a responsible service provider, creating value for customers while simultaneously advancing our sustainability goals. Together, we’re driving positive change — one reconditioned component at a time.

Restoring All 90 Teeth on a Two-Stroke Engine Flywheel

2nd December 2022

Being well known for our repair capabilities, we repair damaged two- and four-stroke engine flywheels frequently. In most cases, a few of the flywheel’s teeth are damaged and we quickly restore these by installing a tailor-made repair insert. We usually do this in-situ, either during a port stay or during a docking.

The situation found on an European-owned 2’300 TEU box ship in September 2022 was very different. When the customer contacted us about a damage to the flywheel, we sent our colleagues from QuantiServ Singapore on board for an inspection.

During the inspection it very quickly became clear that this was no ordinary case, as all ninety teeth were found severely damaged. An in-situ repair of 90 teeth would take too long and would not be cost-efficient either. As the ship was about to be docked very soon, we suggested to the customer to carry out the repair during the upcoming docking in southern China.

The colleagues from QuantiServ China took over the case. They worked out a very attractive proposal that was immediately accepted by the customer. Our engineers and technicians then started all preparation and planning.

Once the vessel was in the yard, the yard workers uncoupled the intermediate shaft, took the 3.5 ton flywheel off the engine and moved it out of the engine room through a narrow slot that they had cut into the vessel’s hull. The flywheel was then trucked to Shanghai, where the highly-skilled engineers and technicians from QuantiServ China immediately commenced to machine it.

They machined off its toothed rim and then shrunk on a tailor-made ring of forged steel onto the ø 3.2 meter flywheel. And to make sure that the ring stays put for the lifetime of the ship, they also installed a total of 135 large bolts. Once this was completed, new teeth were milled.

Milling new teeth obviously took time, owing to the large size of the flywheel. In fact it took five days and five nights of continuous milling!

After completing a few more processing steps, our Shanghai colleagues sent the flywheel back to the shipyard and to a very happy customer. The shipyard workers then completed this repair assignment, by reinstalling the flywheel to the 72-bore engine and by re-coupling it to the ship’s intermediate shaft.

Severely damaged flywheel prior to repair

Ready to be delivered back to the shipyard

Links

The repair of every single tooth on a flywheel as presented above is not something that we do every day. Typically, just a handful of consecutive teeth are damaged. Follow one of the links below to see how we repair these cases in-situ.

Flywheel In-situ Repair on the US East Coast

Another successful flywheel repair assignment completed, in Florida, USA

Flywheel Teeth Dentistry in Hong Kong

In-situ repair of a large 96-bore engine flywheel at Hong Kong anchorage

In-situ Flywheel Repair in Mombasa, Kenya

In-situ Flywheel Repair on a 3’400 TEU Container Vessel in Mombasa, Kenya

Webinar from the Swedish Club: Dealing with Crankshaft Damage

18th November 2022

According to statistics compiled by the Swedish Club, crankshaft damage is the most expensive class of engine damage, with an average claim cost of 1.2 million USD.

In a webinar held on 26 October 2022, a panel of experts from the Swedish Club and from QuantiServ explored the common causes and types of damage to internal combustion engine crankshafts. They also explored different repair options and what can be done to prevent damages from occurring in the first place.

Panelists:

Henrik Karle, Technical Manager, The Swedish Club
Peter Stålberg, Senior Technical Advisor, The Swedish Club
Johannes Roberts, Manager, QuantiServ Sweden

This webinar was brought to you by The Swedish Club in collaboration with QuantiServ Sweden. It was broadcasted live via zoom on 26 October 2022.

Special thanks to the Swedish Club for making it possible. Previous webinars from the Club’s Loss Prevention series can be found here.

More Than 1’000 QS50K Pistons Delivered – And Counting!

4th August 2022

In 2019, following an extensive research and testing period, we have introduced the first QS50K pistons into the market. It was the beginning of a lasting success story: Ever since, we have produced and delivered more than 1’000 pieces, to many different customers.

These pistons are now installed all around the world, in ocean going vessels and in power plants. They are performing extremely well and achieve time between overhauls (TBO) that hitherto were unthinkable. The earliest QS50K pistons have accumulated well over 30’000 running hours and are still in service!

Benefits of the QS50K technology

With the introduction of the QS50K coating technology, QuantiServ has redefined the piston reconditioning process. This proprietary technology was developed by QuantiServ and offers the following important advantages:

- Extremely durable, wear resistant coating, resulting in very long life-time / time between overhauls (TBO)
- Fully automated process carried out by a robot, resulting in a top-quality product due to the robot’s very high accuracy, repeatability and consistency.
- Faster than chromium plating, therefore shorter turnaround times
- Less heat input into the piston, eliminating any residual stresses that over time could develop into cracks
- Environmentally sound, non-toxic process

Availability

We offer the QS50K technology for any engine brand and for any cylinder bore above ø 48 cm. The QS50K pistons that we have delivered so far covered the bore range, from ø 48 cm to ø 98 cm. They were destined for engines manufactured by the big three OEMs, in an approximately 45%/45%/10% ratio.

At this moment, our recon centres in Kruiningen (The Netherlands) and Suzhou (China) are equipped with the required machinery to offer this product. Our large recon centre in Singapore will follow very soon.

24’000 Hour Ring Groove Life Time. Guaranteed!

The quality of our QS50K coated ring grooves is so good that we now offer a 24,000 hour* warranty on fully reconditioned, QS50K coated two-stroke pistons!

*pro-rata, 24,000 running hours or three years after delivery, whichever comes first

To give maximum flexibility to our customers, we offer three different ways of working to chose from:

Reconditioning on exchange. The customer gets a newly reconditioned component delivered from one of our four reconditioning centres. Once he has installed the component into his engine, he returns his old part to us.
Reconditioning of the customer’s own part. The customer sends the component to be reconditioned to a QuantiServ reconditioning centre, where it undergoes professional reconditioning after which it is returned to the customer.
Straight sale. The customer purchases a reconditioned piston from us, without returning an old one.

We can apply the QS50K coating to pistons that are undergoing full or partial reconditioning.

Full reconditioning

The entire top surface and ring groove area is first machined off and then rebuilt by robotic MIG or SAW welding. Thereafter, the piston undergoes final machining before the QS50K coating is applied to the ring grooves. The last step is grinding of the ring grooves, which completes the full reconditioning process.

If it is requested by the customer, then we can coat the top of the piston by a protective layer of Inconel. This can be a good solution for engines that suffer from excessive hot corrosion at the piston top.

Partial reconditioning

If only the ring grooves are worn and if a piston is in otherwise good condition, then partial reconditioning is possible. A precondition is, however, that none of the ring grooves has worn so much that not only the chromium layer but the steel substrate itself has worn. In this case, partial reconditioning is not possible and full reconditioning is the only remedy.

During partial reconditioning, any remaining chromium is removed before the QS50K layer is applied to the ring grooves. All mating surfaces will be skimmed, to remove any signs of fretting corrosion and if there are small internal cracks, then these will be repaired too.

Our reconditioning centres

We operate four reconditioning centres that are strategically located along major shipping routes: Singapore, Kruiningen (The Netherlands), Suzhou (China), Dubai. Each of the four centres carries a large inventory, so it can offer components on exchange in addition to reconditioning the customer’s own part. Both ways of working are available, it is entirely the customer’s choice.

Our reconditioning centres are the most modern ones within our industry. Welding and QS50K coating is typically performed by robots and machining is done on numerically controlled (NC) machines.

QuantiServ Reconditioning Centres — We operate four reconditioning centres globally.

This enables us to provide consistently high quality and short turn-around times at attractive prices.

QuantiServ Suzhou Workshop — The QuantiServ reconditioning workshop in Suzhou, China. The others are in Singapore, Dubai and Kruiningen (The Netherlands).

“Reconditioning” Must Mean More Than to “Put Into Good Shape Again”

20th May 2022

Component reconditioning is very popular

Component reconditioning has many advantages. This is especially true in case of large, heavy components:

Reconditioning usually represents a cost saving of 50 – 70% compared to replacement
Reconditioning a component nearly always takes up significantly less time than fabricating a new one
Long lead times or supply chain crunches are less of an issue, as supply chains are shorter and simpler
No new part might be available when one is needed. To reduce risk and stock keeping costs, OEMs manufacture and sell spare parts for ever shorter time periods only.
Reconditioning results in a smaller carbon footprint than replacement

Given these advantages, it is hardly surprising that component reconditioning has been widely used for many years in industries such as marine and power generation, where components are large and where equipment life is long.

But, what does reconditioning actually mean?

Dictionaries and thesauri usually equate the word “reconditioning” with “to put into working order again” or “to put back in shape”. Proposed synonyms are: To fix, mend, patch, renovate, repair and revamp.

This implies that the goal of the reconditioning process is to put the component back into the state it was before it got worn or damaged.

At QuantiServ, we are convinced that we should do much more than to put a component back into its original, unworn condition. We set the bar much higher for ourselves. After all, we are one of the largest reconditioning companies in our industry and we have in-house research and development resources, that enable us to continuously push the technology envelope. Noblesse oblige, as the French proverb goes.

We believe that whenever a machinery component undergoes reconditioning at one of our four reconditioning centres, we are presented with an opportunity to not just put the part back to its original condition, but to improve on it. We habitually apply new technologies, modern materials and advanced processes to improve component design, leading to a better performance and extended Time Between Overhaul (TBO).

This sets us apart from all the low-cost reconditioning companies. These companies return to their customers components that – in the best of cases – perform as good as when they were new, but never better. Unfortunately, by so doing, these companies forego customer value by providing sub-optimal service.

There are many good examples of how we have lived up to our high standards and have engineered, manufactured and delivered to our customers improved components that have subsequently shown superior performance. An illustrative example comes from a power plant in the Caribbean, that suffered from very short TBOs. Pistons on these 90-bore engines had to be pulled every 3’000 running hours, to replace piston rings, pistons and, sometimes, even cylinder liners. To solve the problem of such unacceptably short maintenance intervals and component life-times, we have thoroughly analyzed and then redesigned some components of this 90-bore, two-stroke engines. Specifically, we have altered the number of piston rings, have coated the piston ring grooves with our QS50K material and have applied a coating to the piston skirts.

The result of these modification is that the TBO could be increased from 3’000 hours to 18’000 hours!

Three piston rings instead of five

In internal combustion engines, piston rings seal the combustion chamber. While the piston rings’ purpose is unambiguous, it is less clear how many piston rings are required, to get the job done effectively. Historically, four or five piston rings per cylinder were deemed necessary on low-speed, two-stroke diesel engines. Simulations and field experience collected by us in recent years has shown that on many engine types, pistons with only three or four piston rings perform better than those with five. “Less is more”, when it comes to piston ring tribology.

Anti-friction coated piston skirts

A well performing forced piston cooling system is essential, especially on engines that operate on heavy fuel oil (HFO) to maintain a relatively low and stable core temperature. If the piston temperature rises above a critical threshold, then galling, scuffing or seizing will occur due to thermal expansion and breakdown of the oil film between the piston and cylinder liner.

The performance racing industry has been using coated pistons for some time already for this very reason. These so-called anti-friction coatings, that are applied to the piston skirts, are essentially dry film lubricants with a very low friction coefficient. This results in low friction forces and a reduction of parasitic drag, while also decreasing heat saturation in the piston skirt and core.

A 90-bore two-stroke engine piston with three piston ring grooves (instead of five) and with an anti-friction piston skirt — A 90-bore two-stroke engine piston with three piston ring grooves (instead of five) and anti-friction piston skirt

Anti-friction coatings offer the following benefits:

They act as a thermal barrier coating and reduce metal-to-metal contact
They increase component life time and TBO due to a lower wear rate
Reduced friction (a parasitic loss) results in a lower fuel consumption
They support oil film formation and therefore reduce the risk of galling, scuffing and seizing, particularly under challenging operating conditions such a running-in, high load operation and load changes

QS50K pistons

An excellent example of us improving engine component design is the development of our QS50K pistons. From a few years ago, many customers reported excessive wear in the piston ring grooves. The customers informed us that pistons with chromium plated ring grooves, which has been the industry standard for decades, would only last for a few thousand running hours. As reported this applied, in equal measure, to new as well as to reconditioned pistons and to many different engine types.

Our engineering and development colleagues started to investigate. They eventually developed an entirely new process of coating the piston ring grooves. They replaced the chromium in the ring grooves with a very advanced, proprietary material formula which has been proven to easily last for 20’000 hours and more. The successful development and market introduction of the patented QS50K coating process is a good example of how QuantiServ developed a solution to problems reported to us by our customers.

Since its introduction, more than one thousand QS50K pistons have entered service. The earliest ones have meanwhile accumulated well beyond 30’000 running hours!

Do talk to us if you have a specific problem with your installation. If machine uptime or performance is lower than it should be, if components wear out too fast, or if they fail prematurely. It is quite possible that we a solution available – perhaps we have already solved a similar problem for another customer. And if we do not have a tried and tested solution ready, then we will be happy to investigate and look for one.

In the case of the Caribbean Power Plant we have also supplied special piston rings that the engine OEM does not have in his portfolio for this engine type. This, in addition to implementing the modifications described above.

Our Reconditioning Offering

Sustainability

QuantiServ’s enduring commitment towards resource reduction and sustainability is demonstrated by our membership in the Association for Sustainable Manufacturing (MERA). We proudly carry MERA’s Manufactured Again Certification Mark, which is a recognizable symbol
that represents the quality, value and sustainability of our processes.

Image Gallery

Example of anti-friction coating on 90-bore piston skirts in our reconditioning centre in Kruiningen, in the Netherlands. Once the anti-friction coating is applied, the piston skirts get cured in an oven. As is usually the case, reconditioning of these piston skirts included the replacement of the four bronze bandages.

Inspection of two 70 Year Old Marine Engines in Switzerland

4th October 2020

One of our most-seasoned engineers recently had the rare opportunity to carry out an inspection and condition assessment on two 70-year old main engines installed on an inland cargo vessel in Switzerland. During its long history, the ship changed ownership two or three times and now belongs to one of Switzerland’s prime construction companies and is used to transport construction gravel to a cement plant, where the gravel gets recycled.

The vessel was originally built in 1948/49 in a shipyard in The Netherlands as an inland cargo vessel. She is a twin-screw design.

When she was built, she had a displacement of 1’246 metric tons, an overall length of 83 meters, a beam of 9 meters and a draught of 2.6 meters. In 1969/1970, she was converted to a self-unloading gravel carrier. Her length was extended by 8 meters, resulting in a new tonnage of 1’447 metric tons.

The two main engines were build by Sulzer Brothers in Winterthur, Switzerland, in 1948 and are connected to the propeller shafts through reversible gearboxes. The engines are of the two-stroke, trunk-piston type and have the following specification:

Engine Type: Sulzer 6TW24
Bore: 240 mm
Rated Speed: 400 rpm
Rated Output: 450 hp each

As can be seen in the cross-sectional view on the right, the engines are equipped with piston-type scavenge pumps, which explains the for the time considerable power output of 450 horse power per engine, or 900 horse power (671 kW) in total.

Our engineer spent a few days on board, compiled an extensive report and after the visit continued to support the customer, for example to identify spare parts.

Because we have a soft spot for antique marine installations, we carried out this assignment and the subsequent customer support activities pro-bono.

An early picture of the vessel on the Rhine river

One of the two main engines, photo taken in 2020

Top view of the engine room, photo taken in 2020

Photo credits:

www.commons.wikimedia.org/w/index.php?curid=59313086
www.swiss-ships.ch
QuantiServ own

Cooling Water System Reverse Engineering

18th May 2019

After 25 years of intermittent operation and of being exposed to the elements, the cooling water radiators of an 3500 kW emergency diesel generator installed in a thermal power plant in Macau had degraded considerably. Thus, the power plant owner decided to replace them.
Unfortunately, the original documentation and specification were not available anymore. Therefore, QuantiServ reverse engineered them and got 12 new elements made by a specialized manufacturer.
The new radiators have just been installed and commissioned and will provide reliable cooling for many years to come.
Although this was a small case, it illustrates the important advantages that reverse engineering provides. Many of the industrial plants that we maintain and repair on behalf of our customers have a lifetime of many decades. But that does not mean that the documentation always survives that long, or that spare parts are still available. And sometimes even the OEM himself, or his sub-supplier, may not exist anymore.
It is thus comforting to know that QuantiServ has the skills, tools and experience to reverse engineer and reproduce all kinds of machinery components, even very complex ones and entire systems.

: New radiators installed

: Hoisting the new radiators in place

: New radiators installed

Our Brand-new Case Study Page is now Online!

17th December 2018

The new QuantiServ Case Study page is now online. It introduces recent work that we have done for customers coming from a variety of industries ranging from Marine, Mining, Hydro and Thermal Power Plants to Oil & Gas.

The cases are sortable by industry and cover services such as in-situ machining, metal stitching, reconditioning and many more. They each include a short description of the problem that the customer was facing, the solution and include many before/after and in-process pictures.

Case Studies

Be Aware of Cam Effect/Ridge Wear that Affects Four-Stroke Crankshafts!

1st December 2017

Whenever a four-stroke engine has accumulated around 60,000 running hours or more, then its crank pins are in all likelihood affected by what is called the “cam effect” or “ridge wear”.

This phenomenon develops over time and manifests itself in an uneven wear pattern that is, with the right tools, easily detectable as a protruding band (“cam”) that goes around the circumference of the crank pin. It usually only develops on engines equipped with grooved bearing shells and its development is a function of time. The more impurities (abrasive particles) the lubricating oil contains, the faster the cam effect develops.

The two major makers of medium-speed diesel engines, MAN Diesel & Turbo and Wärtsilä, have booth issued Service Letters to make their customers aware.

The following pictures are typical and exemplify well how the cam effect develops and what damage it can cause. The pictures were taken during an attendance on a German-owned small tanker, where QuantiServ’s specialists machined one crank pin and polished all the others on the vessel’s single 50/54 main engine. The damage was in fact so severe that in-situ heat treatment (annealing) had to be performed too in order to reduce the crankpin’s hardness, which had increased as a result of the failure.

QuantiServ very much recommends to all owners and operators of medium-speed four-stroke engines to keep a close eye on the condition of the crankpins and to regularly inspect them once they have surpassed around 60,000 running hours. The cost of rectifying the pin geometry in good time pales in comparison to the cost of a repairing a failed crankpin bearing. And fail they will, if no action is taken.

: A failing crankpin. The location of the seizure marks is symptomatic of the cam effect.

: Another crankpin on the same engine. The uneven wear is clearly visible.

: Following in-situ heat treatment, machining of the damaged crankpin.

: One of the crankpins after polishing, with proper geometry restored.

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