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

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
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.

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Repair Details:
  • 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.

Damage around the crankcase door
Damage around the crankcase door
Dressing up one of the repair inserts
Dressing up one of the repair inserts
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
Removal of cracked and deformed material
Stitching-in one of the repair inserts (left)
Stitching-in one of the repair inserts (left)
Metal stitching is physically very demanding and is often performed in tight spaces
Metal stitching is physically very demanding and is often performed in tight spaces
Preparing the engine block to receive repair inserts
Preparing the engine block to receive repair inserts
During stitching in place one of the smaller 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
Badly damaged crankpin
Badly damaged crankpin and crankwebs
Extensive impact marks
Extensive impact marks on the crankpin
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
Blueing check of the completed crank pin
Counterweight landing surface restored
Counterweight landing surface restored
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.

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

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.
One of the crankpins undergoing repair
One of the crankpins undergoing repair

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.

One of the crankpins prior to repair
One of the crankpins prior to repair
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
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.

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Webinar from the Swedish Club: Dealing with Crankshaft Damage

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.

Large Reconditioning Order in China Successfully Completed

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
Robotic welding of pistons
Robotic welding of pistons
Piston rod reassembling
Piston rod reassembling
Six of the piston assemblies ready for delivery

Inspection of two 70 Year Old Marine Engines in Switzerland

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
An early picture of the vessel on the Rhine river
One of the two main engines, photo taken in 2020
One of the two main engines, photo taken in 2020
Top view of the engine room, 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