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Propeller cleaner tested on Royal Navy flagship protects environment and saves fuel
1 November 2024
Engineering experts believe they’ve helped protect the marine environment – and helped the UK’s flagship power through the water more efficiently – thanks to an ingenious cleaning device.
The technology removed 11 kilogrammes of marine life clinging to the propellers of HMS Queen Elizabeth – growth which slowed the vessel down and made her the less fuel efficient.
In the past that cleaning process has had the potential to introduce tiny, possibly invasive bio-organisms from wherever a ship has been into the UK marine environment and ecosystem.
The Royal Navy and BAE Systems – responsible for support and upkeep of HMS Queen Elizabeth and her sister ship HMS Prince of Wales in Portsmouth Naval Base – have been working with UK firm SeaTec, part of V.Group, on an environmental-friendly solution.
SeaTec has developed a combined ‘polisher/scraper/vacuum’ – the firm calls it a closed-circuit propeller polishing system – which safely removes the marine growth without damaging the propeller and runs the water through a series of filters to scrub it of the most harmful contents.First tested on frigate HMS Lancaster, the SeaTec system, which is operated by divers, next tackled the two huge propellers – weighing 33 tonnes and delivering up to 50,000 horsepower apiece – powering the 65,000-tonne aircraft carrier through the water.
The propellers were cleaned before HMS Queen Elizabeth headed off on her maiden deployment to the Far East in 2021 – during which she sailed more than 56,000 miles.
That mission and subsequent activity added 11kg of unwanted marine life – such as barnacles, zebra mussels and tube worms – to the propellers, now safely removed.
As well as adding to a vessel’s drag, the unwanted bio-fouling also impacts the noise signature as the ship powers through the ocean – making her several Decibels louder and therefore easier for potential foes to locate.
The team aboard HMS Queen Elizabeth are delighted with the initial results – the ship is faster, quieter, burns less fuel (clean propellers can cut fuel consumption by 5 per cent, at the same time as reducing greenhouse gas emissions, according to data gathered by SeaTec from other contracts outside the MOD) and there’s no evidence of invasive organisms entering the Portsmouth/Solent ecosystem.
Since cleaning the carrier, the closed-circuit cleaning system has also been successfully used on destroyer HMS Duncan and tanker RFA Tidesurge, removing 13 and 18kg of growth from each vessel respectively.