If Australia gets a submarine deal from France, it will be the first time in more than 40 years that the country has bought military hardware from an ally. The last time was during World War II when Britain sold a number of Short S Class submarines to Australia.
Australia’s Prime Minister Malcolm Turnbull said he had ‘deep and grave’ concerns about French submarines’ capabilities after recent leaks by former Navy officer Herve Morin who claimed they could not detect US nuclear-powered aircraft carriers.
The Australian reported that Turnbull said French submarines are not as ‘quiet’ as those made in Japan by the Australian Submarine Corporation (ASC). The ASC has been lobbying for a submarine deal to be awarded to them.
Australian public broadcaster ABC’s Fact Check unit questioned claims that French built submarines are “noisy”. Their research showed that it is difficult to be sure of the breaching submarines’ capabilities because little information has been provided by the Australian government.
The research showed that all submarines make noise when they move forward at low speeds due to “flow noises” in front and behind the submarine. But if it moves faster, there would be less noise created. The French used a pump-jet propulsion system instead of a propeller which was designed to reduce noise.
The French submarine manufacturer DCNS said the French Navy’s new Barracuda Class submarines were “the most silent” in the world.
According to ABC, Australia’s government had “not released even basic information about how it knows this.” However, they did note that there were some measures which can be taken to improve the ability of submarines to detect other vessels.
The use of sound-absorbing tiles and anechoic coatings would reduce noise emissions. However, they could only be used in small sections of a submarine and would add weight and maintenance costs. Australia Defence organisation said it had “no plans to use these features on the future submarines.”
The US Navy uses sonar to detect other vessels. It’s unclear whether Australia’s using it or not, according to ABC.
ABC said that The French have used “tactical” stealth system which was designed to make it harder for the submarine to be found by other ships, planes and anti-submarine weapons. The French Navy’s website said their submarines had “piercing hulls” to reduce noise. It also uses a “multi-frequency sonar” which gives it the ability to track ships, submarines and torpedo attacks.
It was noted that the Australian Defence organisation could not say whether Australia would use the same sonar.
In conclusion, it was stated that “it is hard to measure the noise made by so-called ‘stealth’ capabilities because there’s not a lot of publicly available information about them.”
However, all submarines make some amount of noise so so it would be difficult for other vessels to detect them if they’re travelling