main engine Archives

Customer Feedback: “Good Quality, Reasonable Cost, Finish on Time”

5th September 2024

Excerpt from an email from the attending Superintendent of the customer to his office, after completion of the work:

"Reasonable costs, where no any additional surcharges were implemented after repair completion / Invoiced amount is corresponding to offer / Not too big amount compared with other vendors, who suggest this type of repair service / Works complete in time (as per the offer) / Good job quality"

Project Overview

QuantiServ recently undertook a challenging and comprehensive repair project on a 46-bore main engine installed on a 12,000 DWT container vessel. The ten-year-old vessel had sustained significant damage to both the crankshaft and engine block. Our team of three highly skilled specialists carried out the repair work in the Caribbean, ensuring the engine was restored to optimal condition and performance.

The entire repair took eight weeks, from start to finish.

Inspection and Proposal

Upon arrival, our team conducted a thorough inspection of the damaged engine components. The inspection revealed extensive damage, necessitating a detailed and precise repair plan. We promptly submitted a comprehensive repair proposal to the vessel’s owner and the classification society. Once the proposal received approval, we commenced the repair work, which included several critical tasks to address the damage.

Whenever we face larger damages, we usually use a 3D scanner to scan the components to be repaired. The highly detailed and accurate geometrical data thus acquired offers numerous advantages. Not only does it accelerate the repair process because it eliminates time consuming manual measurements, it also helps to create very detailed and precise repair castings.

Simulation to show how the repair inserts will fit together

Engine Block Repair

Damage Sustained:

Crankcase door damage on both starboard (SB) and port side (PS)
Cam floors damaged on both sides
Various additional cracks in the crankcase

Our metal stitching repairs are permanent repairs. So much so that we grant up to 5 years of warranty on them.

Total length of cracks/junctions stitched: approximately 6 meters
Number of stitching pins installed: Approximately 1’000 pieces
Number of tailor-made repair inserts installed: 8 (with the larger inserts casted in a classification-approved foundry and shipped to the vessel prior to commencement of the on-site repair)
Pre-fabricated sleeve installed in the lower cylinder liner guide
In-situ line boring and installation of sleeves in two camshaft pockets that were found out of line due to the accident

Our specialists meticulously stitched the cracks and installed the necessary inserts, ensuring the structural integrity of the engine block was fully restored. The use of about 1’000 Castmaster C3 stitching pins and eight custom-cast inserts highlights the extent and complexity required for this repair.

One of the repair inserts — Visual simulation how one of the repair inserts is to be fitted into the block

Removal of cracked and deformed material

Stitching-in one of the repair inserts (left)

Metal stitching is physically very demanding and is often performed in tight spaces

Preparing the engine block to receive repair inserts

During stitching in place one of the smaller repair inserts

The completed repair — The almost completed repair, prior to drilling of some minor holes and painting

Crankshaft Repair

Damage Sustained:

Extensive mechanical damage to one crank pin
Connecting rod, big end bearing housing thrown out of the engine block
Both counter weights thrown out of the engine block, studs sheared off
Deep indents in the crankpin surface
Long cracks, easily visible by naked eye

Repair Details:

Damaged crankpin machined to undersize
Landing surfaces of counterweights milled
Counterweight fastening bolt stubs removed

The crankshaft repair involved machining one crankpin to an undersize diameter and installing a pre-fabricated sleeve in the lower liner guide. These steps were crucial in restoring the crankshaft’s functionality and ensuring the engine’s smooth operation.

Blueing check of the completed crank pin

Installation of new studs, after removal of the broken stubs. — Installation of new studs, after removal of the broken stubs

Customer Feedback

The customer expressed immense satisfaction with the repair results. The attending superintendent conveyed his positive feedback to his management, highlighting the professionalism and expertise demonstrated by the QuantiServ team. He recommended QuantiServ for future repairs on the company’s vessels, underscoring the trust and confidence our services have earned.

At QuantiServ, we pride ourselves on delivering high-quality, reliable repair services that meet and exceed our customers’ expectations. This project is a testament to our commitment to excellence, precision, and customer satisfaction. We look forward to continuing to provide top-tier repair solutions for the maritime industry.

Follow these links for more information about our in-situ and metal stitching services.

Five In-Situ Machining Jobs on Large Two-Stroke Engines in Three Months

29th August 2024

At QuantiServ, we are dedicated to providing exceptional in-situ machining services to the maritime industry.

Over the past three months, our team has successfully completed five significant crankpin machining assignments on large two-stroke marine main engines. These projects, carried out on four different engine types built by the two market-leading OEMs, highlight our versatility and expertise.

Project Highlights

North America: We performed extensive crankpin machining on a container vessel, ensuring the engine’s optimal performance and reliability. Almost simultenously, we also worked on a bulk carrier, deliverig high-quality crankshaft machining services that meet the stringent standards of the maritime industry.
The Caribbean: Our team tackled a challenging crankpin machining job on an oil tanker, restoring the crankshaft to its full operational capacity in less than two weeks.
North Asia: On a Ro-Ro ship, we executed a complex crankpin machining task, demonstrating our ability to handle diverse vessel types with ease.
South East Asia: Another successful project involved a gas tanker, where our team ensured the engine’s reliability and efficiency through crankpin machining and other repair works.

In all these cases, we worked on crankpins from Ø 600 to 900 mm and machined off anywhere from 4 mm to 10 mm, due to excessive hardness and cracks following a bearing failure. Typically the repair work involves machining and then machine polishing of the cylindrical crankpin surface and of the fillets¹. On some of these vessels our specialists worked in a single-shift modus, while on others they worked around the clock in two shifts. It always depends on the customer’s wishes and on her operational requirements.

*The fillets are the radial undercuts at the transition of the crankpin to the crank web.

After machining and polishing — The same crankpin after machining and polishing

Comprehensive Services

In addition to the crankpin machining work, we also provided a range of related services, including:

Planning: Remotely assisting the customer to find the best repair solution and to make arrangements before the vessel even reaches the location where the repair is to be carried out.
Sourcing of Under-Size Bearings: : Ensuring the availability of tailor-made bearings, with short lead time. Under-size bearings have a thicker white metal layer and are usually not available off-the-shelf. They have to be produced on a case-by-case basis. Some of these bearings we produce in-house, others we source from specialized manufacturers.
Reconditioning of Engine Components: Extending the life and performance of critical engine parts in one of our four reconditioning centres.
Other Repair Works: Addressing various repair needs not related to the crankshaft, ensuring comprehensive engine maintenance.

Commitment to Excellence

Each of these projects underscores our dedication to providing reliable and efficient in-situ machining services. Our ability to mobilize almost instanteneously and to perform these tasks on-site in a 24/7 manner, saves our clients valuable time and limits loss of income. Whether it’s a container vessel, tanker, Ro-Ro ship, bulk carrier, or gas tanker, QuantiServ is equipped to handle the unique challenges of each job with precision and professionalism.

We look forward to continuing our tradition of excellence and supporting the maritime industry with our specialized in-situ machining services.

Crankpin machining whereby the cutting tool moves in a continous orbital path around the crankpin, resulting in uniform material removal

Blueing test to verify that the bearing shell makes full and even contact with the crank pin. — Final blueing test to verify that no high spots are present and that the bearing shell makes full and even contact with the crankpin

Note: All photos in this post originate from the five projects, they are not depicting the same project.

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

Large Reconditioning Order in China Successfully Completed

2nd November 2022

Our colleagues working at our reconditioning centre in Suzhou, China, have completed what most likely will be their single largest order of the year 2022.

The work came from an european-owned, 6600 TEU boxship docked in a shipyard in Zhoushan, China. Many components of the 19-year-old, 12 cylinder, 96 cm bore main engine were in need of reconditioning and/or overhauling. Of course our colleagues in Suzhou were more than happy to comply.

The components arrived at our workshop on 30 July 2022 and were returned to the vessel in two batches, on 28 August 2022 and 01 September 2022 respectively. Thus, the work took just took 32 days, from start to finish.

During this time, we reconditioned the following components:

15 pistons: Full reconditioning including coating of the piston ring grooves with the QS50K material
13 piston rods: Reconditioning of the running surface, skimming of the landing surfaces
9 piston skirts: Renewal of the rubbing bandages and skimming of the landing surfaces
12 stuffing boxes: Overhaul and modification of the housings (upgrade)

The work included dismantling, reassembling and pressure testing where required

This case neatly demonstrates that our reconditioning centres have sufficiently many skilled workers and machining capacity at their disposal to handle even the largest reconditioning orders with ease.

Piston assembly — Assembly of the stuffing boxes

Six of the piston assemblies ready for delivery

Metal Stitching Repair on a Small Diesel Engine Bed Plate

18th August 2022

A customer reached out to us in May 2022 in Singapore, asking for our help in repairing a damaged two-stroke engine bed plate. The cast iron bed plate suffered from cracks and missing material, inflicted as consequential damage following a connecting rod failure.

Our experts immediately carried out an inspection on board. They found this main engine bed plate to be repairable, but determined that the damage area could not be accessed properly without removing the engine’s A-frame. The shipowner therefore decided to bring the 19-year old, 100 m long asphalt carrier alongside a ship repair yard in Singapore.

“We are very satisfied with your service.”

Customer’s Technical Superintendent, by email, August 2022

While the shipyard’s personnel dismantled the ø 38 cm bore, japanese-made engine, our specialists prepared a repair plan and discussed it with the customer and classification society. Simultaneously, they arranged for a tailor-made repair patch to be made, including a set of accompanying classification certificates.

In late June 2022, once the engine had been suitable dismantled, three metal stitching specialists from QuantiServ Singapore carried out the bed plate repair. They first removed all damaged and deformed material and dressed up the facture. They then installed the newly fabricated cast iron repair patch with Castmaster™ stitching pins. They repaired all cracks in the same manner, including a 150 mm long one that had not been visible until the deformed material had been removed.

Once all stitching pins had been installed, our specialists then added high-strength locks, made of heat treated steel. These are always installed perpendicular to the fracture line and serve to distribute stresses over a wider area. They also add additional strength to the repair.

The completed repair was thoroughly checked by Magnetic Particle Inspection (MPI). The attending classification surveyor witnessed this. And last but not least, our in-situ team carried out a laser alignment check of the main bearing pockets. This was done to rule out any deformation in the bedplate due to the impact forces exerted upon it by the broken connecting rod.

Damage area prepared for stitching repairs

Classification surveyor attending the Magnetic Particle Inspection (MPI) — Class surveyor witnessing Magnetic Particle Inspection

Installation of stitching pins along the crack line

Magnetic Particle Inspection (MPI) of the completed repair

Preparing the repaired bed plate for laser alignment check of the main bearing pockets

In-situ Machining the World’s Largest Four-Stroke Diesel Engines

12th August 2022

Ø 64 cm bore, 90 cm stroke, 2’150 kW (2’880 hp) power per cylinder: The world’s largest four-stroke engines are very mighty machines indeed!

These powerful engines were built during the late 1990’s, mostly in a 6-cylinder configuration. With a nominal power output of 12’900 kW, they found popular application as single propulsion engines in multi-purpose cargo vessel of about 20’000 DWT size.

During 20 – 25 years of operation until now, these engines have accumulated more than 120’000 running hours each. In terms of number of engine revolutions, this is equivalent to a car driving for 1.8 million kilometers (1 million miles)!

It is therefore hardly surprising, that after that many running hours signs of wear were found on the crankpins of these engines. As is often the case on medium-speed, four-stroke engines, the crankpins were suffering from what is called “cam effect” or “ridge wear”.

Has your four-stroke engine accumulated around 60,000 running hours or more?

Although the crankpins might appear to be in good condition, it is very likely that they suffer from the cam effect (also known as ridge wear) and are in need of machine polishing. If this is not done, then you might face a failure soon!

Usually, then the cam effect will manifest itself in two ways:

Through uneven wear in horizontal direction, with nearly no wear at the centre of the pin and at the edges, but with easily noticeable wear to the left and right of the oil bore.
The pin is not affected evenly throughout its circumference. The cam effect is usually most pronounced at about 30 – 45 degrees after Bottom Dead Centre (BDC). For this reason it is called “cam effect” – the pin is not perfectly circular anymore.

QuantiServ appeals to owners and operators of medium-speed four-stroke engines to sensitize the crew about the cam effect. We highly recommend that the pins are carefully checked whenever an engine overhaul or bearing replacement is carried out. If any uneven wear patterns are detected, then the pin must be machine-polished to restore its proper geometry before any new bearings are installed and the engine is restarted.

If the cam effect is detected in good time, then machine polishing of the pins is usually sufficient to correct the problem. After machine polishing, the crankshaft will be ready again for several years of continuing operation. Whether standard bearings or undersize bearings will have to be installed after polishing will depend on the actual situation.

If, on the other hand, the cam effect goes undetected for too long, then a crankpin failure is almost inevitable. Such was also the case here on the first engine. Heat treatment and machining was therefore necessary and was swiftly carried out by our Swedish specialists. Having seen the excellent result and now aware of the cam effect, the customer tasked us to machine polish all pins on this engine and on the sister vessels, which is why we eventually polished about 70 pins in quick succession but in different ports.

All work described above was carried out on board by our Swedish in-situ specialists. They were supported by our reconditioning experts that meanwhile worked on those engine components that were removed from the vessel for an intervention ashore. These components were sent to our reconditioning centre in Kruiningen, The Netherlands, where they underwent thorough overhauling and machining works.

By the time of writing in August 2022, we have overhauled around 70 cylinder heads and have re-bored a similar quantity of big end bearing housings. Machining the big end bearing housings became a necessity due to excessive ovality in the bore.

Newly overhauled cylinder heads in our workshop

The Benefits of a Global Footprint: Connecting Rod Repair “On the Fly”

24th March 2021

If your ships operate globally, then you benefit from relying on a service partner that has a truly global footprint. This post neatly exemplifies this fact.

The subject is an American-owned, 9’000 TEU container ship with an 82-bore main engine. The vessel experiences a crosshead bearing failure while crossing the Atlantic. We repaired it “on the fly” with a minimum of down-time:

During the last days of 2020, the vessel experiences a severe crosshead bearing failure close to Bermuda island. The crosshead pin and connecting rod are found severely damaged and are in need of repair or replacement. Our experts assess the situation and give remote assistance to the crew during removal of the connecting rod from the engine. Once that is done, the vessel continues its journey towards Europe with one cylinder cut out.
On 15 January 2021, the vessel arrives in Algeciras. The damaged connecting rod gets offloaded and is transported by truck to our workshop in Genoa.
It arrives at our works on 18 January and at once undergoes repairing. After completion of the repair, we ship the connecting rod by air freight from Milan, via Doha, to Singapore. It arrives in Singapore in the morning of 05 February 2021.
Our technicians in Singapore assist the crew to reinstall it. After a short and successful trial run, the ship continues its journey towards the South China Sea.

QuantiServ operates out of 15 locations that are strategically placed along major shipping routes or close to important ports. Wherever your ships go, we are never far away.

Corrosion protected and ready for dispatch

15 Years Service Experience With Metal Stitched 2-S Engine Columns

25th January 2021

In October 2020, kindly acting upon our request, the crew of a 53’000 DWT bulk carrier checked the condition of the guide rails on their main engine. Specifically, they checked whether a metal stitching repair that was done in 2005 is still in good condition. Besides a periodical visual inspection, the crew carried out liquid penetrant testing (PT) to check for the presence of cracks.

The inspection revealed that the repair is still in perfect condition. No abnormalities such as cracks or loose stitching components were found.

At the time of writing, this engine had accumulated over 77’000 running hours / 15 years in service since the said metal stitching repair was carried out in October 2005 in Kure, Japan.

Location of the 660 mm long crack that was repaired in 2005 — Location of the 660 mm long crack in the gear column, repaired in October 2005

At that time, the engine had 27’000 hours on the counter. Meanwhile, until October 2020, the engine has accumulated 103’000 running hours, 77’000 of them were with repaired guide rails.

To the best of our knowledge, this makes this engine the longest-running one with structural repair to the columns (A-frame) or bedplate carried out by metal stitching.

The permanent repair done in 2006 involved the installation of stitching pins and locks from Lock-N-Stitch to repair a 660 mm long crack. The crack was located in a 13 mm thick steel plate in the gear column of the 6-cylinder, 48-bore two-stroke engine.

The vessel remains in service and we continue to monitor it. Not because we have even the slightest doubt about the quality or durability of the repair, but because she is a living testament to the permanence of our metal stitching repairs.

Area repaired at the side of the intermediate gear wheel boss

The general area where the crack was repaired

Close up of the repaired area — A close-up view of the repaired area

After application of dye penetrant — Non-destructive examination: Application of dye penetrant

Red dye cleaned, developer about to be applied — Non-destructive examination: Dye penetrant removed

Developer applied - no defects visible — Non-destructive examination: Developer applied

Non-destructive examination: Outline of locks and stitching pins just barely visible

Metal Stitching Repair of Two-stroke Engine Bedplates

4th January 2021

This post introduces metal stitching as an attractive solution to repair cracks in two-stroke engine bed plates.

Background

The term “metal stiching” is most commonly associated with the repair of cast iron parts, as an alternative to welding, to which cast iron does not lend itself easily. Due to its brittle nature, cast iron tends to fail again rapidly after welding, unless the welding takes place at very elevated and uniform temperatures. These conditions are hard, if not impossible, to achieve in most workshops, let alone at site.

It is less commonly known that metal stitching is also an increasingly often used process for the repair of steel parts, where welding actually would be possible. There are good reasons for chosing stitching over welding, even in steel.

First and foremost, metal stitching is a cold process and thus does not lead to deformation or latent heat-induced stresses in the part being repaired. Post-repair (in-situ) machining to correct these deformations is therefore rarely required.

Second, as we have shown through independent labaratory testing, a metal stitched junction that has been made by a qualified operator using Lock-N-Stitch tools and stitching components, exhibits a tensile and fatigue strength that is equal to, or better, than that of a welded junction.

During the last few years, QuantiServ have gained extensive experience in applying the metal stitching process to crack repairs in two-stroke engine bedplates and columns. Two instructive cases are discussed below, both involving container ships with 96-bore engines.

On the first vessel, the stitching was carried out in stages, during successive port stays. On the second, the repair was carried out during a regularly scheduled dry docking in China.

Case 1: Bed Plate Metal Stitching During Successive Port Stays

In the course of a crank case inspection, a 800 mm long crack was found in the main engine bedplate on board a 15,500 TEU container vessel in 2019. Contacted by the ship owner, we carried out an assessment. It revealed that the crack would propagate quickly if the engine, a 14-cylinder, 96-bore one, would continue to operate at, or near, its nominal speed.

We proposed to the customer to carry out the repair while the ship remained in service. As the thirteen year old vessel was engaged in a “high-rate/less-time” trade, the customer of course jumped at the opportunity to get the crack repaired without any vessel off-hire. Following a review of the vessel’s trading pattern, we decided to carry out the repair during successive port stays during the vessel’s Northern European loop.

Our specialists commenced their work as soon as the vessel was alongside in port and did not stop anymore until the engine had to be restarted. They then rested during the short voyage to the next port, where they continued in the same manner.

While working, our specialists discovered that the crack in fact was about 300 mm longer than had previously been reported by the crew. This meant that the time in Europe was insufficient to repair the crack in its entirety.

Our specialists revisited the vessel a few months later, again in Europe, to repair the previously unreported section of the crack. All in all, it took seven port stays of a few hours each to repair the bedplate.

Attendance	Voyage	Number of port stays
First	Antwerp – London	4
Second	Bremerhaven – Antwerp	3

In total, we repaired on this bed plate over 800 mm of crack in steel plates with thickness ranging from 18 – 50 mm, without a single day of off-hire or otherwise interfering into the vessel schedule.

To repair this bed plate, metal stitching was chosen over welding because it has the following advantages:

The vessel stayed in operation throughout the repair. The stitching was done in stages during port stays, a few centimeters at a time. With welding, this would not have been possible. The vessel would have had to be taken out of operation for around three weeks.
Lower costs, compared to welding. A competitor proposed to carry out repair by welding in 20 days. We repaired it by stitching in 12 days. Less time spent means less costs.
For metal stitching, a hot work permit is not normally required. Such a permit would be very difficult to get in container terminals, meaning that welding would not have been possible from a safety point of view.

Crack runs from the girder side plate down into the oil sump — The crack runs from girder side plate down into the oil sump

Crack without the sealing compound that was temporarily applied — View of the crack without the sealing compound that was temporarily applied

The completed repair, prior to cleaning and painting

Case 2: Bedplate Stitching During Dry Docking

The second case discussed here concerns an 8-year old, 13,000 TEU container vessel with a 12-cylinder, 96-bore main engine. The crack discovered on this engine was quite similar to the one described above.

Since the crack was discovered shortly before the vessel was scheduled to undergo a routine dry docking, it was decided to repair it during the docking period in China in 2020.

The crack extended over a length of 750 mm in steel plates with thickness ranging from 18 – 50 mm. Repairing it took our specialists eight days, working in single shifts.

Crack runs from girder side plate down to oil sump — The crack runs from the girder side plate down into the oil sump

Stitching of the crack in progress — Metal stitching of the crack in progress

The completed repair prior to repainting

The first two-stroke diesel engine that we have metal stitched has meanwhile accumulated 77,000 hours. We repaired a 600 mm long crack in the gear column (A-frame), in 2006. The repair is still in perfect condition today.

04 January 2021

The two repairs presented above were carried out using stitching components from the American company Lock-N-Stitch. We would like to stress that we have labaratory-tested other products available in the market and that we have found their strength to be insufficient for demanding applications like these.

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

Flywheel In-situ Repair on the US East Coast

4th March 2019

Starting up a handymax bulk carrier’s 48-bore, two-stroke main engine with its turning gear engaged resulted in the turning gear shattered and in damage to 12 consecutive teeth on the flywheel.

The turning gear was damaged beyond repair and had to be replaced. Not only was its housing shattered but the planetary gears were completely destroyed too.

Faced with the costly and unpalatable reality of most likely having to replace the flywheel as well, the ship management company turned to QuantiServ for help. Always liking a challenge when we see one, we engineered and delivered a comprehensive solution that consisted of the following:

Inspection on board
CAD and FEA modeling to engineer an economical yet structurally very strong solution
CNC machining of repair inserts in our workshop
In-situ machining of the flywheel on board
Stitching the repair inserts in place

Our in-situ machining and metal stitching specialists carried out the work in February 2019, during the vessel’s port stay in Florida, without interfering in her schedule.

QuantiServ carries out a number of gearwheel repair assignments every year, mostly for industrial, marine and mining customers.

: Flywheel was damaged over 12 teeth

: CAD simulation, used for engineering a repair

: 3-D printed prototype of a repair insert

: Prefabricated repair insert

: Flywheel undergoing crack testing after repair

: The completed repair

Brand New Light Surface Grinding Tools Now Available for Sale!

27th October 2018

We are asked frequently, whether we are selling the in-situ machining tools that we have developed and manufactured and that our specialists use in the field. While such requests are of course flattering and while we appreciate that other companies find our tools appealing and would like to purchase them, we have up to today always politely declined such request. The reason is that we first and foremost see ourselves as a top-notch in-situ machining company and not as a tool manufacturer. Our tools are thus a means to end – the more accurate and efficient they are, the better the result of our machining assignment that our customer comes to enjoy.

Our very newest Light Surface Grinding machine (LSG) has now proven to be so popular, that we have decided to break with tradition and to make it available for sale.

The machine was designed to be as compact and portable as possible. It has an adjustable base, no heavy adapter plates are therefore necessary. Its total weight is 30 kg (66 lbs). This is significantly less than any comparable machine currently on the market and means that it does not have to be sent as cargo to a ship or power plant, but can be brought along as checked-in luggage.

The tool’s main purpose is to quickly and accurately skim the cylinder liner landing surfaces at the top of medium-speed engine blocks. It can be used to machine diameters of 360 – 670 mm, which makes it suitable for engines with a bore size of 260 – 500 mm. Additional accessories to also skim the landing surface on the cylinder liner are also available.

The advantages of the Light Surface Grinder (LSG) are many:

High accuracy
Fast to set up and easy to use
Compact design
No adapter plates are necessary as the machine’s base is continuously adjustable
A single machine covers the range from ⌀ 360 – 670 mm
Total weight = 30 kg (66 lbs)

Two-stroke Bedplate Line Boring in Mexico

5th March 2018

When a six year old bulk carrier suffered main bearing failures on its Japanese-made main engine, QuantiServ was called in for an initial inspection and for discussions on how to arrange the repair in the fastest and most economical way. The inspection in Veracruz, Mexico, showed that main bearings # 7 and 8 failed and that the crankshaft as well as the main bearing pockets were damaged.

The crankshaft was beyond repair and had to be replaced by a new one. The bed plate, on the other hand, could be recovered by line boring. With the engine frame lifted up, QuantiServ’s in-situ specialists carried out

a thorough inspection of the bedplate, including NDT crack detection and hardness measurements
laser alignment checks before line boring
line boring of main bearing pockets # 7 and 8
laser alignment checks after line boring
blueing checks

The work was carried out successfully while the vessel was alongside in the shipyard in Mexico.

: Setting up the boring bar

: Line boring

: Flatness measurement

: Flatness measurement

Reconditioning of Fourteen 96-bore Cylinder Covers

30th November 2017

In November 2017, our Reconditioning Centre in Shanghai carried out reconditioning of fourteen cylinder covers for a major European ship owner. These covers came from one of the world’s largest container ships, equipped with a 14-cylinder, 96-bore main engine.

All fourteen cylinder covers and all fourteen exhaust valves were reconditioned within a period of less than one month, while the vessel was undergoing steel work at a shipyard in Qingdao.

This was the third vessel out of a series of similar vessels for the same customer. QuantiServ carried out the reconditioning work for all these vessels.

Significant Reconditioning and Field Service Job in Shanghai

30th November 2017

In September our Reconditioning Centre in Shanghai carried out a a major reconditioning and field service order for an Iranian-owned tanker that was docked in a Chinese shipyard. This example shoes well the breadth of QuantiServ’s offering.

The following components were reconditioned:

8 piston rods
7 piston crowns
7 cylinder covers
6 exhaust valves
7 crosshead pins
plus a number of smaller, related components

We also sourced for the customer a couple of new crosshead and crankpin bearings while we re-babbitted others, such as for example guide shoes.

QuantiServ engineers also carried out the overhaul work on board, supervised the oil flushing and attended the seatrial after the docking. We also replaced the stern tube shaft seals and in-situ polished some of the crankpin journals.

All the work was completed in 32 days.

Polishing All Main Journals and Crankpins on World’s Largest Engine

1st September 2017

QuantiServ in-situ machining specialists from China, Sweden and Singapore joined forces in a shipyard in China to carry out in-situ polishing on one one of the world’s very largest diesel engines. The 14-cylinder, 96-bore engine is installed on a 14,000 TEU container ship.

Our engineers and technicians worked in two shifts, around the clock, seven days a week to machine-polish 17 main journals and 14 crank pins while the vessel was docked in Beihai Shipyard, Qingdao, undergoing steel work. It was one of the most extensive polishing jobs that we have ever carried out. And it was done in record time!

All the necessary dismantling and reassembling work was carried out by us as well. In a case like this it pays off that many of our in-situ personnel are multi-skilled – they don’t only do the machining work, but can conduct any mechanical work as well if required.

In addition, our reconditioning centre in Shanghai also carried out cylinder cover reconditioning for a sister ship, belonging to the same customer, that was docked in the same shipyard a few weeks earlier.

Lateral surfaces before and after in-situ machining

In-situ machining of lateral surfaces on 20V32 engine block in Bangladesh

21st November 2016

Lateral surfaces before and after in-situ machining

In-situ machining of lateral surfaces on a 20V32 engine block in a power plant in Bangladesh

In October 2016, QuantiServ received an urgent request to carry out in-situ machining on a 20-cylinder 32-bore engine block in a power plant in Bangladesh. During the replacement of the crankshaft it was noticed that both lateral surfaces of main bearing cap number 5 showed signs of severe fretting and were in need of machining.

Immediately, in-situ machining equipment was prepared at QuantiServ’s Dubai workshop and was sent to site. Once the equipment had arrived at site, QuantiServ’s engineers from Dubai performed in-situ machining on the engine block to achieve a clean surface that was free from damage. The in-situ machining process was constantly monitored by laser to ensure perfect alignment and adherence to very tight machining tolerances.

The main bearing cap was sent to a local workshop in Bangladesh for machining and installation of compensation plates. This process was supervised by QuantiServ’s engineers. Once the machining was completed, all mating surfaces for the main bearing cap were checked with marker blue to ensure a perfect fit.

Once the work was completed, a final check by laser on the assembled bearing cap showed that both the bore alignment and diameter fully conformed to the engine maker’s specification.

: Severe fretting corrosion at the lateral surface guiding the main bearing cap

: In-situ machining of the lateral surfaces

: Lateral surfaces after in-situ machining, all fretting removed

: Engine block laser alignment check

: Main bearing cap with compensation plates installed

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

11th August 2016

Milling and tapping, preparation for the teeth inserts to be installed

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

QuantiServ received a request from a customer to repair the serration on a main engine flywheel. The vessel called Dubai, where QuantiServ engineers carried out an inspection. They found that five teeth were missing; an isolated one and four in a row.

While the vessel continued her voyage to Africa, our technicians manufactured new teeth and fitted bolts at our workshop in Dubai. They then brought these jointly with the required in-situ machine tools to the vessel, which had meanwhile reached the port of Mombasa in Kenya. There, the machining and installation work was carried out by four engineers in two shifts, around the clock, while the vessel was undergoing cargo operations.

Prefabricated teeth and fitting bolts

The work was completed successfully within a tight time window of 72 hours without delaying or otherwise interfering with the vessel’s normal sailing schedule.

The final result, five missing teeth replaced

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Project Overview

Inspection and Proposal

Engine Block Repair

Damage Sustained:

Repair Details:

Crankshaft Repair

Damage Sustained:

Repair Details:

Customer Feedback

Project Highlights

Comprehensive Services

Commitment to Excellence

Links

Another successful flywheel repair assignment completed, in Florida, USA

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

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

Background

Case 1: Bed Plate Metal Stitching During Successive Port Stays

Case 2: Bedplate Stitching During Dry Docking

In-situ machining of lateral surfaces on a 20V32 engine block in a power plant in Bangladesh

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