Customer Requirement

Tufcot were approached in the first quarter of 2020 by one of our long-standing customers and one of the leaders in the oil and gas sector – APL Norway AS.

An upcoming project working on an FPSO, (Floating Production Storing Offloading), operating off the East Coast of India required some large diameter composite bearings for the Swivel Stack assembly on an STP Buoy.

These were required on a strict deadline and at a size and section that made them difficult to source.

Tufcot were more than happy to assist with a solution and supply with our proven T100G material, manufacturing capacity and previous experience.

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Project Outline

Typically, applications for the oil and gas sector are subject to hostile and varying environments.

This is a problem that is further exacerbated when considering the challenges for an FPSO – with so many feed and process connections having to allow for swell and heave in the moored position the Swivel Stack is key in turret mooring and fluid transfer systems – one of the key considerations is flexibility including rotational function and smooth operation on such a large piece of equipment.

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In this instance the requirement for the bearings was to be a composite material with a diameter of over 2600mm and a section of only 18mm x 20mm but with tight tolerances on the diameter, section and wall thickness.

Any dimensional anomalies would result in failure of the assembly and considerable downtime and ultimately cost for production on the FPSO.

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Tufcot Solutions

Large diameter rings of this size hold their own very unique problems for manufacture –

Raw Material – Manufacture & Material Control

Tufcot’s extensive experience in large bearing material manufacture meant that we were able to produce a cost effective large single use pattern for the raw material.

With the assistance of one of our suppliers Quad CNC, we were able to produce an accurate pattern to begin the material manufacture. Our large capacity marine bearing wrapping machine easily handled the size.

Using our own unique cure control process ensured the integrity of the material and size maintaining concentricity to within just 2mm – vital for the rest of the manufacturing process.

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Pre-Machining Preparation

To ensure material at this size remains stable during machining we were able to leave the material on the pattern whilst curing due to the capacity of our large oven.

A secondary cure with the material flat on the oven floor ensured complete stress relief of the material. This meant the material condition and accuracy were almost perfectly concentric.

Allowing Tufcot to use the minimum possible machining allowance giving significant cost saving to the customer in both material cost and machining time.

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Machining – Capacity, Stability, Control & Accuracy

Machining of a bearing at this size and section presented its own unique difficulties.

On this occasion working with one of our trusted subcontractors who has an extensive list of large machining equipment, capability and capacity meant this was no problem.

Goodman Metalworks experience in machining composite materials meant we were able to machine the bearings on the large vertical borer.

Machined fully supported to maintain concentricity and ensure the tight tolerances were met accurately (as low as 0.05mm).

Accuracy of this level at these diameters is a challenge but using innovative custom tooling and the capacity and capability of Goodman’s we achieved the required result.

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Packaging & Logistics

Bearings of this size and section naturally require considerable care and protection during transport from the UK to Norway due to their flexibility and obvious fragility as a composite material.

The problem was that for parts with such a low weight the packing crate would have to be substantial enough to protect the product but light enough to ensure the customer wasn’t put to extra cost during transport. We had to design a crate with reduced mass where possible to ensure the product could be manually handled safely during transport whilst fitting exactly round the dimensions of the finished part. Assisted by Quad CNC we managed to achieve this.

Moving items around the size this project involved meant we had to think a little further beyond normal freight methods. DP Services Machine Removals came to our assistance using some of their specialist vehicles to cope with the unusual size of the material and finished packed products ensuring safe transport from start to finish of the project.

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At almost 3m in diameter Tufcot are proud to have been able to produce one of the largest small section composite bearings made to date for this type of application – completed ahead of schedule (even during the Global Pandemic), delivered on time to exacting tolerances and to the highest quality.

Our experience, technical and manufacturing knowledge and, where required, highest calibre of manufacturing partners allowed us to hit every specification to support our customer 100%.

With extensive experience of supply into the oil and gas sector, Tufcot have a range of technical materials and solutions for a range of bearing applications.

Please contact our technical office to see if Tufcot can assist with your next or upcoming projects.

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