Helping Mor Engineering develop new mooring line solutions for Floating Offshore Wind

Background

Mor Engineering are at the forefront of development of new products and services for the floating offshore wind (FLOW) sector. The business is a specialist commercial consultancy based in Falmouth, founded in 2018 by Dr Sam Weller.

Sam has over 23 years’ engineering experience, having worked in both industry and academia. Sam is highly experienced in engineering analysis of marine energy devices and mooring systems, including condition monitoring – a field which will be crucial for the successful development of Floating Offshore Wind (FLOW) in UK waters.

The Challenge

A recent study by Marine-i partner ORE Catapult called ‘Mooring and anchoring systems – market projects’ highlighted the need for condition monitoring systems for FLOW Turbines. It pointed out that if 95GW FLOW turbine capacity was installed by 2050, this would require 23,223 mooring lines. 

While not all lines are likely to require condition monitoring instrumentation, there is a real need to understand the performance and integrity of flexible materials. A particular subset of polymers and elastomers have characteristic working strain ranges which are significantly greater than metals. 

Although the use of these materials in the offshore sector is not new, their short- and long-term performance is not fully understood. Whilst forces can be monitored using load pins and shackles, no subsea system currently exists which is capable of monitoring large strain ranges. This can have severe safety implications, such as the dangers of snap-back to deck personnel if mooring lines suddenly come apart. 

Mor Engineering’s Approach  

Dr Sam Weller explains: 

“Our initial market research identified that the technologies which are currently employed for measuring strain and displacement tend to either be generic equipment which require marinization, be unreliable in hostile environments or have limited operational lifetimes. 

“Therefore, there were two options open to us address this challenge. Either we could adapt and improve existing measurement technology to suit this new application or we could develop a significantly different concept. 

“The latter approach is clearly higher in risk, but potentially avoids having to make the compromises that would be necessary to achieve functionality with existing equipment. The proposed sensor topology has been the subject of R&D in other fields but has yet to be applied to offshore applications. 

“In order to determine concept feasibility, this project involved the design and fabrication of prototype sensor topologies, integration into a use-case (synthetic rope), physical testing and analysis. This would bring its maturity to technology readiness level (TRL) of 3.”

Successful testing of the new concept

A desk-based study was initially carried out to determine which technologies are likely to be suitable in a subsea environment as well as initial scoping of appropriate manufacturing and fabrication techniques for the prototypes.

The Marine-i project supported Mor Engineering in the crucial testing phase at DMaC. Jonathan Maiden of University of Exeter explains:

“The Dynamic Marine Component (DMaC) test facility is a purpose built test rig that aims to replicate the forces and motions experienced by marine components in offshore applications. The test facility is based within the Renewable Energy Research Group of the University of Exeter at Penryn Campus, Cornwall. 

“DMaC was the perfect test facility for this project. The rig is capable of replicating dynamic tensile forces up to 20 tonnes, static tensile forces up to 40 tonnes, and displacements up to 1m. Our team worked closely with Mor Engineering to ensure that the testing regime yielded the exact data that they needed.”

Dr Sam Weller adds:

“ We were really pleased to have this expert testing support from the Marine-i project, which enabled us to fully assess the performance of this new concept. Marine-i funding has enabled Mor Engineering to carry out proof of concept work on two mooring line condition monitoring approaches by subjecting fabricated prototypes to a series of ISO 18692-2:2019 quasi-static and dynamic tests using DMaC. Particular emphasis has been placed on loading regimes which result in large strain ranges, to allow comparison of measured data from the prototypes over sufficiently large tension and strain ranges.”

Prof Lars Johanning, Programme Director for Marine-i says:

“The work being carried out by innovative Cornish companies such as Mor Engineering will be crucial in enabling us to realise the full potential of Floating Offshore Wind in the Celtic Sea and beyond. These pioneering businesses are advancing our knowledge and understanding in ways which will have worldwide implications for the marine renewable energy industry.”

[Image: Mor Engineering]