SCORCH is a major industry-funded research program for the offshore industry. Existing guidelines (API, BV, DNV and ISO) for estimating wire rope and chain corrosion have been derived from measurement in cold waters. No guidance on the effects of seawater temperature on the life of the materials used to construct offshore moorings is available, despite temperature being a major factor on rate of corrosion and thus the life of such materials. The lack of accuracy of existing design rules is an acknowledged issue within the industry.
The objectives of the SCORCH are to provide participants with:
- Design guidance on the specification of wire ropes and chains to maximise their design service life for given site conditions, in particular in tropical waters.
- Design analytical tools, underpinned by field and test data, to estimate the design service life of steel wire mooring ropes and chains for given input site conditions.
The overall program of the SCORCH will include the following tasks:
- Conduct a state of the art literature review on corrosion in seawater.
- Acquire and analyse material samples - the objective of this task is to gather real world samples of mooring materials and from these to better describe the effect of local conditions on the failure mode and rates of failure of these materials.
- Conduct field studies to quantify the effects of the marine environment on service life - series of field tests on wires, wires ropes and chains samples will be conducted to quantify the effects of external factors driving corrosion in marine environments.
- Conduct laboratory studies to quantify the effects of the marine environment on service life.
- Conduct data analysis and modeling focused on corrosion and wear – both may interact together as wear will remove the protective layer, therefore increasing corrosion rate, and corrosion will affect the material internal composition and therefore its mechanical properties and ability to resist wear.
- Design Guidance - data analysis and modelling will be reviewed by Bureau Veritas with the aim of deriving both recommendations and application guidance that will be fit for class rules and other industry codes of practice (e.g. API RP 2SK).
The present scope of work will be conducted by world experts, including Prof. R.C. Chaplin for wire ropes and Prof. R.E. Melchers in the fields of corrosion and reliability, together with highly recognized personnel from AMOG Consulting and Bureau Veritas. Estimated completion time is 2.5 years.
