A news article that caught our eye this week concerned the widespread adoption of “bubble curtains”. If you’re familiar with the offshore industry, the term won’t cause bemusement but, be aware, Google searches could bring up curtains with a bubble design!
Bubble curtains, in terms of offshore, are becoming widespread, but first, let’s summarise what they actually are. Put simply, they’re a technological advance using air bubbles to protect Marine life in offshore oil and wind industries.
Companies are exploring the benefits of enveloping their work with walls (or curtains) of bubbles that distort noise waves.
Their genesis began in California in 2003 and 2004, when massive hammers were used to drive new pilings into the seabed for the San Francisco-Oakland Bay Bridge. Early tests, without bubble curtains, did show deaths of fish and autopsies revealed punctured bladders and damaged kidneys.
“When a pressure wave hits an air bubble, it will compress the bubble, then it will expand again, so energy is lost,” said Bud Abbott, a marine biologist. Bubbles absorb sound.
Germany, like the States, has seen its own marine deaths from offshore wind farms in the North and Baltic seas. The 1000 ton wind turbines create high decibel sound waves which have deterred porpoises from swimming there within a 20 mile radius. A limit of 160 decibels was imposed by the German governments and bubble curtains have played a huge part in this.
We need to put these numbers into perspective – normal chat is measured at 60 decibels, a jet engine is 140 decibels and anything above 130 decibels causes pain to humans.
The technology has taken a long time to adopt from its invention in 2002. This is because it is a complex and costly operation and it’s also a challenge to keep the perforated hoses, or bubble curtains on the seabed. But with sound levels amplified underwater, it’s a challenge that needs to be met to protect sea creatures.
James Fisher are blazing a trail with this and are commissioned with a key project in Taiwan supporting the installation of jackets on turbines, that follows their success with bubble curtains and their “noise mitigation vessel”.
‘We are delighted to have secured this new contract, ’says Barry Craig.‘ It shows a vote of confidence in the work we have been doing in the region – work which we have successfully completed despite the difficulties and limitations of a global pandemic.’
News like this is welcome for marine life and our industry.
“We owe it to our children to be better stewards of the environment. The alternative? – a world without whales. It’s too terrible to imagine.”
Pierce Brosnan
