Equipment Re-chocking After an Engine Room Fire

Overview

QuantiServ recently undertook a significant repair project in Europe involving a 20,000 DWT chemical tanker built in 2016. The vessel had sustained severe damage in an engine room fire, which destroyed the main engine’s, auxiliary engines’, and shaft generator’s epoxy resin foundations. The shipowner contracted QuantiServ to carry out the necessary repairs, including the alignment work of the equipment.

Scope of work

Main Engine and Auxiliary Equipment

The single main engine, a German-made medium-speed engine with a nominal output of 8’000 kW, along with the three auxiliary engines and the shaft generator, required a complete foundation redo.

Given the vessel’s modern propulsion system comprising of a gear box, controllable pitch propeller (CPP) and shaft generator, precise alignment was critical to ensure optimal performance and, especially, longevity.

To recast the foundations, we used our very own two-component QuantiCast epoxy resin. Simply speaking, we used the epoxy to fill up the voids between the welded steel foundation of the ship and the equipment to be installed. The height of these voids  ranged from about 25 mm below the shaft generator to about 50 mm below the main engine. This was very well in range, as for QuantiCast we allow a minimum chock thickness of 10 mm and a maximum one of 70 mm.

In total, 26 cans, equating to 260 liters of material, were used to pour the various foundations in this project. The work was completed efficiently within a week, showcasing the team’s experience and dedication.

Quality Assurance

During pouring of the resin, ten samples were taken. Once fully cured, they were subjected to hardness testing in our laboratory. As expected, the results were perfect, with hardness values ranging between 45 and 67 Barcol, significantly exceeding the minimum acceptable limit of 35. This ensures that the repaired foundations can withstand the operational stresses and will last for the vessel’s service life.

Advantages of QuantiCast Epoxy Resin

As already mentioned, QuantiCast was the material of choice for this repair assignment. QuantiCast is QuantiServ’s own product and is uniquely suited for such projects as it offers several key advantages:

  • No shrinkage or creep, maintains precise alignment
  • Ease of application, short construction time
  • Excellent adhesion on various substrates (concrete, steel, …)
  • High compressive and impact strength
  • Highly resistant to chemicals, solvents and moisture
  • Tough, durable and very corrosion resistant
  • Low total cost

Conclusion

This project underscores QuantiServ’s capability to handle all kinds of marine and industrial equipment installation works efficiently and effectively, be that for new installations or, as in this case, a repair project.

QuantiServ is able to provide end-to-end solutions, ranging from foundation machining (which was not required in this case), through equipment alignment, carrying out the necessary static calculations and drafting a chocking plan, all the way until the eventual damming and pouring works. And of course we have the chocking material available for sale, with or without additional services.

Read more about our epoxy resin services by following this link:

Read more

Propeller Shaft Line Work on New ULCS

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

Read more

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!

Shaft alignment check by laser
Shaft alignment check by laser

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
A severely damaged stern tube bearing bush
Machining the outer circumference of a stern tube bearing bush
Machining the outer circumference of a stern tube bearing bush
Stern tube line boring
Stern tube line boring
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
Calibrating the outside diameter of the bearing bush at our workshop in Shanghai
Inspection of a large stern tube bush at the shipyard
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.

Very Extensive Crankshaft and Block Repair on a Passenger Ferry

Overview

QuantiServ recently completed a large-scale repair assignment on a passenger ferry. The ferry was built in the year 2000 and is equipped with four 12-cylinder, 46-bore main engines, with a nominal power output of 12.6 MW each.

In early 2024, two of these engines required extensive repairs, having each accumulated over 120,000 running hours and having suffered a recent failure.

QuantiServ was contracted to carry out the repair of both engines. As additional defects were found during the repair, the work turned into a sizeable project that took almost four months to complete.

Our in-situ machining specialists from Sweden carried out all work during the winter months of 2023/2024, while the vessel was out of operation during the low season.

One of the two crankshafts was removed from the engine and underwent repair on the vessel's car deck.
One of the two crankshafts was removed from the engine and underwent repair on the vessel's car deck.

Damage

The following damages were found. They were all addressed by our specialists during the repair.

Engine Number 1

  • Crankpin bearing failure
  • As a consequence: Multiple cracks, excessive surface hardness of 600 – 680 HB

Engine Number 2

  • Failure of four crankpin bearings
  • Crankshaft bent
  • Failure of one adjacent main bearing
  •  A collapsed main bearing saddle, as a consequence of the heat generated
  • Poor fitting of another bearing saddle
  • Severe cam effect on all other crankpins
Multitude of cracks in the crankpin journal
After cutting off some material from the crankpin, a multitude of cracks became visible. They were caused by the rapid temperature raise and fall during the bearing failure.
In-process hardness measurement during machining. The areas with increased hardness are easily visible.
In-process hardness measurement during machining. The dramatic temperature changes resulted in changes in the local microstructure that are easily visible.
Surface hardness of up to 680 HB following the failure. The acceptable limit is 300 HB.
Due to excessive heat generated by the failed bearing, the surface hardness had increased to 600 - 680 HB. The acceptable upper limit is 300 HB.

Detailed Work Performed

All repair works was done while the vessel was berthed during low season.

Engine Number 1

Crankshaft Repairs:

  • Heat Treatment and Machining: One crankpin was machined to an undersize of -3.00 mm.
  • Polishing: Two main bearings were polished to ensure smooth operation.

Engine Number 2

Due to damage found on the engine block, the crankshaft was removed so that line boring on the block could be carried out. Heat treatment and in-situ machining on the crankshaft was carried out on the vessel’s car deck.

Crankshaft Repairs:

  • Heat Treatment: Four crankpins and one main journal underwent heat treatment.
  • Machining: The treated components were machined to undersize diameters ranging from -2.00 to -5.00 mm, depending on their condition.
  • Straightening: The crankshaft, found bent with a run-out of 1.50 mm, required peening (in-situ straightening).
  • Polishing: All main journals and crankpins, exhibiting strong indications of the “cam effect,” were polished.

Engine Block Repairs:

  • Bearing Saddle Realignment: The overheating of one main bearing caused misalignment, necessitating the replacement of the bearing cap and subsequent line boring.
  • Bearing Cap Adjustment: Another main bearing cap showing a gap with the cylinder block was corrected.

Additional Improvements

In addition to the primary repair tasks, QuantiServ addressed machining work previously carried out by another company on some of the crankpins. The fillets were not nicely cut, and the radius around the oil hole needed improvement. Our specialists refined these areas, ensuring optimal performance and longevity of the crankshafts.

Summary Table of Work Done

 

Engine Work done
# 1 Heat treatment and machining to -3.00 mm undersize of one crankpin
Polishing of two main bearings
# 2 Removal of the crankshaft for external heat treatment and in-situ machining
Machining to undersize diameters of -2.00 to -5.00 mm
Peening (in-situ straighening) to correct a bent crankshaft with 1.50 mm run-out
Polishing of all main journals and crankpins
Replacement of a bearing cap and line boring due to misalignment
Adjustment of a main bearing cap gap with the cylinder block
One of totally five crankpins that our specialists machined to under-size
One of totally five crankpins that our specialists machined to under-size
The mirror-like finishing on one of the crankpins.
Impressive, mirror-like finishing after polishing of the crankpins.

Conclusion

This extensive in-situ repair project on a passenger ferry highlights QuantiServ’s expertise and ability to perform critical repairs without interrupting service.

The phenomena known as “cam effect” or “ridge wear” could be identified as reason for the bearing failures and the ensuing, rather extensive and therefore costly, repairs. It is therefore very important that ship owners and operators are sensitive to this issue and regularly check the condition of the crankpins once their engines have surpassed aproximately 60,000 running hours.

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!

Read more

Line Boring of a Locomotive’s Diesel Engine Block

Our in-situ machining specialists recently carried out line boring of the main bearing pockets on a 20-cylinder, two-stroke engine. The engine is installed in an American-built diesel-electric locomotive and operates in Scandinavia.

Line boring became necessary due to the seizure of three main bearings. We performed the repair work in our workshop in Gothenburg, Sweden.

We routinely carry out line boring on all kinds of diesel and gas engines, mostly on main bearing and camshaft bearing pockets, or to install sleeves to stop water leaking along the cylinder liners into the oil sump.

This particular job stands out due to the innovative design of the engine. And not only is the design innovative, it was very successful too. Between 1965 and 1983, almost 29’000 such engines were built!

Engine particulars:

  • 20-cylinder V-engine
  • 2’900 kW (3’950 hp) output
  • 230 mm bore, 250 mm stroke
  • 900 – 950 rpm nominal speed
Line boring of the main bearing pockets
Line boring of the main bearing pockets

Innovative engine design

In a nutshell: This engine is very compact, very powerful and it runs at a rather high speed for this size of engine: 900 – 950 rpm. This results in a rather remarkable maximum piston speed of just over 12 m/S at mid-stroke1. Because of its high power and compact packaging, this engine has a high power to weight ratio. This is achieved through innovative design features that are worth looking at. Here we look at three of them.

1) 45 degree angle between A- and B-bank

V-engines are a common configuration for internal combustion engines. In a V-engine, the cylinders are arranged in two banks, which form a “V” shape when viewed from the front of the engine. The angle between these two banks is known as the “V-angle” and can vary significantly between different engines.

Most V-engines have a V-angle of 90 degrees. However, this engine type uses a V-angle of only 45 degrees. This design choice can have several implications for the engine’s performance and characteristics.

A 45-degree V-angle results in a more compact engine design compared to a 90-degree V-angle. This can be particularly beneficial in applications where space comes at a premium, such as in high-performance sports cars, in motorcycles or, you guessed it, in railway locomotives.

However, a smaller V-angle can also result in increased mechanical stress and vibration, as the forces generated by the pistons are not evenly distributed across the engine block. This can lead to increased wear and tear on the engine components, and may require additional mechanisms to counteract the imbalance.

In terms of performance, a 45-degree V-angle can potentially offer improved balance and smoother operation compared to a 90-degree V-angle. This is because the smaller angle allows for better primary balance and reduces vibrations.

In conclusion, while a 45-degree V-angle can offer some advantages in terms of compactness and potentially smoother operation, it also presents challenges in terms of increased mechanical stress and complexity of manufacture. As with any engineering decision, the choice between a 45-degree and 90-degree V-angle will depend on the specific requirements of the application.

2) Non-offset V-engine block

Some V-engine blocks have cylinders that are not offset (when viewed from above), meaning that the cylinders of both banks are exactly aligned. This design is known as a non-offset V-engine block. One advantage of this design is that it results in a more compact engine, as the cylinders are arranged in a more space-efficient manner.

However, there are also some disadvantages to this design. One potential issue is that it can result in increased mechanical stress and vibration, as the forces generated by the pistons are not evenly distributed across the engine block. This can lead to increased wear and tear on the engine components, and may require additional mechanisms to counteract the imbalance.

Overall, the choice between an offset and non-offset V-engine block will depend on the specific requirements of the application. While a non-offset design can offer some advantages in terms of compactness, it may also have some drawbacks in terms of increased mechanical stress and vibration. It is important for engineers to carefully consider these trade-offs when designing an engine.

3) “Blade and fork” connecting rods

The blade and fork type connecting rod arrangement is a unique way of joining two pistons to a single crankpin. In each pair of engine cylinders, a “fork” rod is divided into two parts at the big end and a “blade” rod is tapered from the opposing cylinder to fit this gap in the fork. This type of connecting rod has long found application on for example V-twin motorcycle engines (by BSA and Harley Davidson, among others) and V12 aircraft engines. The most famous example of a “blade and fork” engine is probably the Rolls Royce Merlin aircraft engine. Close to 200’000 such engines were built over many years. They were installed in many very famous aircrafts, such as the North American P51 Mustang, the Supermarine Spitfire, the Avro Lancaster and the Hawker Hurricane.

The advantage of this arrangement is that it allows both cylinders and rods to be in the same plane, as is required by an non-offset engine block. It also makes the motions of the two pistons identical. In the aircraft world, there were additional reasons for using fork-and-blade rods, rooted in history. Both Allison and Rolls-Royce produced V-12 engines which used knife-and-fork rods.

However, there are also some disadvantages to this arrangement. The underlying physics and manufacturing practice supporting plain journal bearings have improved to the point that big-end bearings no longer require the support of a full-width bearing. This means that side-by-side con-rods can now be used instead of fork-and-blade rods, which are more complex to manufacture.

Overall, the blade and fork type connecting rod arrangement has its advantages in terms of simplifying design and making piston motions identical, but it is more complex to manufacture than side-by-side con-rods. With advances in bearing technology, side-by-side con-rods have become a viable alternative. However, the choice between the two arrangements ultimately depends on the specific requirements of the engine design.

Work performed

The work that we carried out to get this 20-cylinder engine block back into good working condition consisted, broadly, of the following tasks:

  • Laser alignment and dimensional check
  • Hardness check and Magnetic Particle Inspection (MPI) to search for cracks
  • Line boring of the 12 main bearing pockets to remove existing fretting corrosion. We machined all main bearing bores to nominal dimension.
  • Blue fitting of the bearing caps

Read more about line boring

1This is an approximation calculated according to the formula PSmax = 250 x π x 950, where 250 is the piston stroke in millimeters and 950 is the engine speed in revolutions per minute

20-cylinder engine block at workshop
The 20-cylinder, welded engine block in our workshop. Note that the gear train is centrally located.
The block turned on its side with main bearing caps removed.
The block turned on its side, main bearing caps removed
Blueing test of the main bearing cap serration
Blueing test of the main bearing cap serration

Metal Stitching Repair on a Small Diesel Engine Bed Plate

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

Damage location
Damage location

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.

Damaged bed plate prior to repair
Damaged bed plate prior to repair
Damage area prepared for stitching repairs
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
Installation of stitching pins along the crack line
Stitching in the repair patch
Stitching in the repair patch
Magnetic Particle Inspection (MPI) of the completed repair
Magnetic Particle Inspection (MPI) of the completed repair
Magnetic Particle Inspection (MPI) of the completed repair
Magnetic Particle Inspection (MPI) of the completed repair
Preparing the repaired bed plate for laser alignment check of the main bearing pockets
Preparing the repaired bed plate for laser alignment check of the main bearing pockets

15’000 TEU Container Ship Intermediate Shaft In-situ Machining

Our colleagues from QuantiServ Shanghai have just completed an intermediate shaft repair assignment on a 15’000 TEU container ship.

While underway to a southern Chinese port, the almost new vessel had suffered a breakdown to one of its line shaft bearings. Running steel to steel as a consequence of the bearing failure, the intermediate shaft got severely damaged.

QuantiServ Shanghai got contacted while the vessel was on tow to one of Chinas largest shipyards in the greater Shanghai area.

Our experts immediately got to work and presented to the shipowner and shipyard a repair plan and schedule, before the vessel even reached the shipyard. The plan included the re-design of the line shaft bearing, the design and fabrication of special in-situ machining tools and the execution of the work in three shifts, around the clock. All stake holders agreed to the plan.

Once the tools had been fabricated, our technicians performed the following work on board the vessel, while alongside in the shipyard. Some of the tasks had to be carried out multiple times, for example laser alignment checks before, during and after machining.

  • Laser alignment checks and alignment calculation
  • Dimensional and hardness measurements, non-destructive crack testing
  • Removal of cracks, shaft journal area machining to under-size, then polishing
  • Shaft alignment adjustment
  • Bearing load jack-up tests

Our six technicians performed the work in two shifts, around the clock. The entire repair took just seven days to complete to the full satisfaction and appreciation of the shipowner, shipyard, classification society and shaft line bearing OEM.

 

Key data of the installation:

  • Intermediate shaft total length: ~ 39 m
  • Shaft diameter: 790 mm
  • Shaft journal length: 1’200 mm
  • Max continuous engine power transmitted through shaft: ~ 53’000 kW
Intermediate shaft in-situ machining
In-situ machining (cutting)
Measuring of the diameter
Measuring of the diameter
In-situ polishing
In-situ machine polishing

Line Boring Work on Large Hydraulic Forming Press

Last month, our colleagues from QuantiServ Shanghai completed an in-situ repair assignment on two large hydraulic forming presses. The two presses, that have a capacity of 2,000 tons each, are installed in a factory in Northern China. They are used to manufacture automobile chassis parts for BMW and Mercedes Benz, among others.

The situation on both presses was almost identical. Specifically, it was the gearbox sections at the upper ends of the press that were in need of repair. A total of six bearing housings (2 x 3 each) were found to be worn. Their diameters, concentricity and coaxiality were all out of tolerance.

Large hydraulic forming press
One of the two 2,000 ton hydraulic forming presses that we worked on

To bring the bearing housings back into specification, our in-situ specialists line bored them. Thereafter, they installed specially manufactured bushes. Non-destructive crack testing and multiple laser alignment checks prior, during and after the repair completed the work.

To minimize expensive down-time, the work was carried out around the clock, 24/7, to the full satisfaction of the customer.

Installing the boring bar
Installing the boring bar
Laser alignment check in progress
Laser alignment check in progress
During line boring
During line boring
Coaxiality calculation
Coaxiality calculation

Stern Tube Machining: Two Case Studies and a Time-Lapse Video

Within the marine industry, in-situ machining of stern tube bearing pockets or of bearings themselves belong to a group of line-boring assignments that we carry out very frequently. In this post we would like to introduce two recent cases, one performed in Las Palmas, Canary Islands, and the other in Singapore.

Case 1: Machining of stern tube forward and after bearing pockets in Singapore

Damage to the stern tube bearings is found during the routine dry docking of a vessel in a shipyard in Singapore. Upon this discovery, the ship owner turns to us for advice. As this is evidently an unplanned and serious case, our specialists mobilize very quickly and carry out an initial laser check of the pockets’ alignments and geometries. The check reveals that the bearing pockets are misaligned and that the ovality that is measured is excessive.

The customer concurs that line boring presents itself as the best remedy. Again, our machining specialists mobilize quickly and rectify the poor alingment and ovality. Both the forward and after bearing pockets are machined. Working around this clock, this is acomplished in just five days.

We arrange two new bearings to be made in Spain on an urgent basis. Once they are delivered, we supervise their installation at the shipyard in Singapore. A final laser alignment check confirms that the alignment is correct now. We also carry out a load test of the entire shaft line and attend the sea trial, which goes smoothly.

Case 2: Machining of stern tube after bearing pocket in Las Palmas, Canary Island

A Norwegian ship owner decides to upgrade the stern tube bearings and seal assembly on a 20-year old ship to a newer, improved design. The upgrade means that the after bearing pockets has to be machined to accomodate the new bearing bush and seals.

Our work scope is as follows:

  • Measure stern tube diameter using a micrometer
  • Find the existing center line through laser measurement
  • Set up the CLB80 line boring machine inside the stern tube and align it with the help of lasers
  • Machine the stern tube according to drawings
  • Final measurement of the stern tube using a micrometer and laser measurement equipment

As is usually the case with stern tube bearing bushes, three different inner diameters (Ø525, Ø524 and Ø523 mm) have to be machined. The  total lenght of the of the stepped area is 935 mm. Two QuantiServ specialists from Gothenburg, Sweden, complete the work in two weeks.

They use our new CLB80 line boring machine that we designed and built ourselves. This machine is capable to very accurately bore holes with Ø140 – 600 mm that are up to 10,000 mm long. Its flange facing capability ranges from Ø90 – 700 mm.

Here is a time-lapse video of the line boring work performed in Las Palmas. The laser alignment and measurement works taking place before and after the line boring are omitted from the video to keep it short.

 

Two-stroke Bedplate Line Boring in Mexico

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.

Lateral surfaces before and after in-situ machining

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

Lateral surfaces before and after in-situ machining

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.