The Challenge:

Despite the incorporation of self-cleaning systems in Offshore Supply Vessel tanks more than two decades ago, many operators in the UK still opt for manual cleaning of tanks in between operations. This has a number of drawbacks, uppermost of which is the safety factor. Manual cleaning is one of the most hazardous activities still undertaken today. Added to that, manual cleaning involves quayside downtime, which is costly and time consuming

The Response:

Since it was founded, AMS Global Group has been committed to identifying ways of enhancing safety in the sector and to streamlining and optimising operational processes by challenging conventional ways of working to bring about improvements.
In 2016, as a first step to optimising OSV tank cleaning, we switched from flushing lines with water in favour of flushing them clean by using pressurised air. It achieved the same results and reduced waste water by almost 50%.
In 2018/2019 we started pushing for the use of self-cleaning systems – which had been incorporated in most OSVs built over the past 25 years – to be revisited. To do this, we successfully enlisted the support of a number of major operators, who agreed to take part in trials which would enable us to gather data which we believed would highlight the benefits of adopting the self-cleaning system.
We collated data over a six month period, monitoring the differences in time taken to carry out the cleaning by manual cleaning as opposed to self-cleaning, and the difference in costs between the two systems. We also noted the number of enclosed space entries by personnel.
This was followed a by a period of independent verification.
During the trial Clients A & B employed manual cleaning, Client C used self-cleaning.

  • Cleaning Hours Billable Hours Tank Cleaning Costs Enclosed space entries
    Client A 83.15 87 £21,750 71
    Client B 78.10 92 £23,000 58
    (Self Clean) 24.45 0 £0 0


We also carried out trials which saw Client A manual tank cleaning as per their normal process (unmanaged), Client B working with guidance from our surveyors to try to reduce waste (managed). This included using air instead of water to clean the vessel  lines and certain other processes before they started to use water.

The data recorded shows that Client A’s unmanaged cleaning produced 279.48MT of waste at a disposal cost of £55,896; Client B, using our managed guidance, produced 124.08MT of waste, less than half the waste of Client B, at less than half the disposal cost (£24,816). Self-cleaning produced 132MT of waste at a disposal cost of £26,400. A similar amount of waste produced between Client B and self clean – but no additional cleaning costs.

The Result:

Following the trials, which demonstrate the clear benefits of the self clean system, AMS Global Bulk Cargo Surveyors and AMS Global Marine Technical team have invested a considerable amount of time, working with vessel owners to help train crews to understand and operate their self clean systems. Owners continue to report excellent results after adopting the self clean process.

“The driving force for us in campaigning for companies to revisit self-cleaning of tanks, was to improve safety. That has been and always will be, key for us.” AMS Global Group

If a self-cleaning system is employed:

  • It negates the need for confined entry, improving safety
  • It negates working at height, improving safety
  • It reduces time in port and downtime – vessels can be cleaned while traveling between port and site, with waste carried back to port and discharged as part of their normal waste
    • Unmanaged manual cleaning – 07.45hrs down time per tank
    • Managed manual cleaning with AMS Global support – 04.36 down time
    • Self clean – 00.00 down time
  • It significantly reduces costs
    • No labour costs, only disposal costs
    • Cuts downtime at harbour berth
  • It can reduce waste produced
  • It reduces congestion quayside because there is no need for a squad of tank cleaners plus associated kit


  • Reduces total project cost
  • No requirement to be berthed while cleaning
  • No confined entry/permits
  • No tank cleaning costs

The future

AMS Global is now working with a local university to develop an innovative new line flushing tool.