The CSOV, on which the work was performed, under construction

Epoxy Chocking of a Retractable Thruster in Vietnam

QuantiCast is a very versatile material, that we often use in grouting jobs big and small. In the latter category falls a chocking assignment recently carried out in Vietnam. It took place on a 88 m long Construction Service Operation Vessel (CSOV), under construction in one of Vietnam’s prime shipyards for an European owner. Once completed, the vessel will be employed in building offshore wind parks.

The vessel is equipped with two steerable thrusters (also known as Rudder/Propellers), two transverse thrusters and one retractable thruster. Particularly on the retractable thruster, perfect initial alignment is very important alignment. And not only that – the alignment must also remain accurate and stable througout the life of the vessel. For this reason, chocking retractable thrusters with epoxy resin is the norm.

Since QuantiCast was the shipyard’s epoxy resin of choice for this project, we would in this post like to briefly outline the various steps of support that we usually give to shipyards. Not only for this project, but in general whenever we are contracted to carry out equipment installation work using epoxy resin:

The CSOV under construction on the slipway
The CSOV under construction on the slipway
  1. Designing the foundation jointly with the shipyard.Finding an economic and efficient solution while closely respecting the equipment maker’s technical requirements.
  2. Deciding on the size and location of the individual chocks under consideration of the the load and the positions of the holding down and jacking bolts. See sketch below.
  3. Calculating loads and tightening torques of the holding down bolts, ensure that they comply with the specified limits imposed by the epoxy resin manufacturer and the vessel’s classification society.
  4. Creating a chocking plan, which is then submitted either by the shipyard or by us to the classification society for approval.
  5. Once the chocking plan is approved, we supply the correct quantity of epoxy resin.
  6. Pouring the foundation at site.
  7. Labaratory testing of the samples taken.

The total footprint of the 16 individual chocks supporting this retractable thruster amounts to 1.6 m2. Each chock is 35 mm high, well within the 10 – 70 mm range acceptable for the QuantiCas material. The total amount of material used is 86 litres.

Although this was a small project, it nevertheless shows the comprehensive offering and involvement that the QuantiServ epoxy resin experts are routinely providing to their customers. Read more about our epoxy resin services by following this link:

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The properly aligned retractable thruster standing on jacking screws
The retractable thruster standing on jacking screws
Simplyfied chock layout sketch
Simplyfied chock layout sketch
Damming in place, prior to pouring of the epoxy resin
Temporary damming material in place, prepared for pouring the epoxy resin
Epoxy resin after curing, prior to removal of the damming material
Epoxy resin after curing, prior to removal of the damming material
Epoxy resin after curing, prior to removal of the damming material
Epoxy resin after curing, prior to removal of the damming material

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:

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Compressor Skid and E-Motor Baseplate Grouting

Our epoxy resin specialists just finished a grouting assignment in a petrochemical plant in Germany. It consisted of the installation of a large compressor skid and of the corresponding electro motor.

For such projects, where the task is to install large machinery base frames or sole plates on a concrete foundation, we typically use a three-component epoxy grouting compound. Three-component grouts include, in addition to the usual epoxy resin and its hardener, also an inert aggregate that acts as a filler material. Typically, silicon dioxide (quartz sand) is used as aggregate. It makes up the bulk of the mix, about 85% by weight.

Epoxy resin compounds are ideally suited for application on concrete. They possess a much higher resistance to many chemicals than concrete and therefore act as a physical barrier, protecting the concrete. Their compressive strength is also superior to concrete.

And since they experience virtually no shrinkage during curing nor creep, they are ideal for maintaining critically aligned equipment firmly in position throughout their long life time.

Scope of work

The customer asked QuantiServ to perform the following services:

•  Select the grouting material suitable for the purpose
•  Define grouting standards and requirement (i.e. concrete roughness, pouring temperature,…)
•  Develop a detailed site grouting procedure
•  Supply the grout material and deliver it to site
•  Carry out the pouring at site, including damming and other related work

The material that we chose is Chockfast Red from ITW Performance Polymers. About 2.5 m3 of it was used for this job.

The work at site consisted of three steps:

1. Grouting of the anchor bolt cavities

2. Grouting of the centrifugal compressor/gear box sole plate and of that of its electro motor

3. Grouting of the approximately 100 mm gap between the concrete foundation  and compressor/gear box skid

Click on the pictures on the left below for a larger view of these steps.

Electro motor aligned on foundation block
Electro motor aligned on foundation block
After grouting of the anchor bolts
After grouting of the anchor bolts
Grouting completed, damming about to be removed
Grouting completed, damming about to be removed

Number of Trained QuantiCast Applicators Grows Steadily

In 2020, we have introduced QuantiCast into the market. QuantiCast is QuantiServ’s very own brand of pourable epoxy resin. It is a top modern chocking or grouting system that offers a number of advantages over competing products:

  • 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
  • Possibility to modify the hardener to resin ratio, to vary pot life and curing time
Successful graduates of our training program in July 2022

QuantiCast is most often used as equipment foundation in marine and industrial environments. It is equally popular in new equipment installation, as in retrofit projects and repair.

To keep up with the material’s increasing demand, we constantly keep on training and certifying applicators. Our in-house training courses equip them with the necessary skills and knowledge to master all situations and applications, such as static pours and resin injections.

We would like to congratulate the July 2022 cohort for having successfully completed their formal training, which consisted of a theoretical part, a practical part and an examination! They are now ready to join our experienced applicators to continue their learning in the field.

Follow the links below to learn more about epoxy resins and the services we provide, or about QuantiCast.

Epoxy Resin Services

 

QuantiCast

 

QuantiCast Epoxy Resin Now Globally Available!




We are happy to announce that after the completion of extensive development and testing work, our very own epoxy resin compound is now globally available for purchase through the QuantiServ organization, starting from 01 January 2021 onwards.

The product is called QuantiCast. It was developed to suit a very wide range of applications in various industries. QuantiCast is an advanced chocking and grouting material for indoor and outdoor use.

This highly durable, non-shrinking material is characterised by high compressive and impact strength. It is absolutely non-poreous and is resistant to a wide range of chemicals, such as hydrocarbon fuel and lubricanting oils, solvents, sea water and many more.

Epoxy Resins that are to be used for marine applications do require classification society type approval. QuantiCast is type approved by DNV-GL and by Lloyds Register.

QuantiCast is priced very competitively. Do ask us for an offer!

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Wrapping of a rudder shaft at QuantiServ Italy

New Video: Wrapping of Propeller Shafts and Rudder Stocks

Shaft wrapping is an activity that our specialists perform on a regular basis, mostly for new ships while they are under construction.

Whenever the design of a vessel mandates that the propeller shaft or rudder stock lies exposed to open seawater, then it should be protected against electro-chemical corrosion. This type of corrosion occurs in the presence of (sea-) water and air (or dissolved oxygen) and the usual way of avoiding it is to coat the shaft with a protective layer of fiberglass.

The following picture shows an example of a rudder stock showing severe signs of corrosion. This is the very outcome that wrapping prevents.

The wrapping process as such is very well established and the results are excellent. During dry docking, we have recently inspected some shafts that we have wrapped ten years ago. We found the wrapping in still perfect condition.

Witness here how our specialists are doing it:

Protecting exposed rudder stocks with fiber glass

QuantiServ’s resin engineers are used to work on a very wide variety of equipment. They are equally versed in repair jobs as in new installation work.

The work shortly described here falls into the latter category. In December 2016 we received for fiber glass wrapping two rudder stocks from a multipurpose frigate currently under construction in an Italian shipyard. The shipyard used to carry out the wrapping by themselves, in the yard. But they lacked the expertise and the right equipment, so decided to give these two rudder stocks to QuantiServ for wrapping in our workshop in Genoa.

The work included the sandblasting of the area to be wrapped, the verification of the surface roughness, the wrapping and final coating itself, as well as the spark testing. The surveyor from the shipyard, who attended the whole process, appreciated the result and said that the speed as well as quality of the work was superior compared to the earlier ones done by the yard.

Because of the good service and result, the shipyard intends to have the next few rudder stocks done at QuantiServ Genoa too.