Crankpin Grinding in 18 Hours, Between Christmas and New Year

True to our credo of “whenever, wherever”, our in-situ machining specialists in Singapore completed a repair assignment during the final days of 2021 in just 18 hours.

At 22:00 on 29 December 2021, at a time when most people traditionally enjoy seasonal festivities and spend time with their loved ones, they boarded the ship with just a few hours notice. The vessel, a German-owned 4200 TEU box ship had arrived in Singapore 9.5 hours earlier and was now waiting for them on anchorage. Once our specialists were on board, the vessel proceeded to the terminal while our colleagues immediately went to work on one of the three Japanese-made auxiliary engines. This engine had suffered a crankpin failure on one of its units.

The engine is equipped with a hardened crankshaft. This means that the crankpin could not be machined but had to be ground. Through the night, our two specialists ground the pin from 260.00 mm to 259.50 mm so that the first undersize bearing can be fitted.

In-situ crankpin grinding
In-situ crankpin grinding

At regular intervals during and after the grinding and subsequent polishing work, our two in-situ specialists verified the dimensional accuracy and the hardness of the pin. The final hardness was measured to be 625 HB, which is a very good value. And for final verification, our specialists also checked the contact area on the completed pin. For this, they used a specially manufactured template and engineering blue.

Our specialists completed their work and disembarked from the vessel at 16:00 on 30 December 2021. It took them just 18 hours to repair the crankshaft!

Fifty minutes later, after the completion of cargo operations, the vessel left Singapore for China. The ship crew will install the new – 0.50 mm undersize bearing shells once they arrive on board and will then restart the engine.

Verifying the contact area on the completed crankpin
Verifying the contact area on the completed crankpin
Surface roughness measurement on the completed crankpin
Final surface roughness measurement

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

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:

  1. 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.
  2. 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.
  3. 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.
  4. 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.

Severely damaged crosshead bearing bore
Severely damaged crosshead bearing bore
Close-up of the damaged area
Close-up of the damaged area
While sailing with one cylinder cut out
While sailing with one cylinder cut out
After initial cleaning
After initial cleaning
Remachining of the bore
Remachining of the bore in Genoa
Crosshead bearing bore after machining
Crosshead bearing bore after machining
Corrosion protected and ready for dispatch
Corrosion protected and ready for dispatch
Connecting Rod ready for dispatch
Connecting Rod ready for dispatch

Nuclear Power Plant Emergency Diesel Generator Block Repair

The operational requirements for emergency diesel generators (EDG) installed in nuclear power plant are very strict and demanding. In case of an emergency event leading to the loss of off-site power, a nuclear power plant’s EDGs are meant to supply independent, redundant power. From this follows that they have to start reliably and quickly  under any condition and must be able to take on load almost instantaneously, which generally means within about 10 Seconds. This is tested regularly under real-life conditions, according to the prevailing nuclear codes, standards and regulations.

This testing regimen of sudden load changes puts an enourmous thermal loading on most of the EDG’s internal components and on its auxiliary systems. Excessive wear and tear is therefore to be expected and is indeed a small price to pay for ensuring plant safety.

For years, QuantiServ has been supporting nuclear power plant operators and contractors serving them with specialist services throughout the long service life of the plants. We are happy to play a small, but nevertheless important role in ensuring safe and reliable electricity supply from whatever source.

The enclosed pictures show the machining of an impressively large, 20-cylinder engine with a rated output of 4000 kw, a cylinder bore of 240 mm and a stroke of 230 mm. It suffered from a small internal defect, caused by wear and tear, that we successfully remedied in our workshop in The Netherlands in 2020.

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.

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.

In-situ flywheel repair on a 3400 TEU container vessel in Mombasa, Kenya

milling-and-tapping-quantiserv

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

In-situ flywheel repair on a 3400 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

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

The final result, five missing teeth replaced