With the Royal Navy (RN) working hard to cast off the "Jonah" reputation of its Astute class nuclear attack submarines, BAE Systems has successfully completed the latest RN boat Artful’s maiden dive. The third of the British A boats, which are billed as the most advanced submarine in the world, Artful submerged while tied to the BAE dock at Barrow in Furness, Cumbria as part of its commissioning process.

The Astute class has had something of a checkered history since the first (HMS Astute) was launched in 2007. From the very beginning, the submarine was plagued by a series of mishaps, which delayed it entering service. Problems with its reactor and turbine, which kept it from reaching top speed, were followed by a serious leak due to a faulty pipe cap, and electronics faults.

Even worse was an embarrassing grounding of Astute in 2010 off the Isle of Skye, and violence erupted in 2011 when a seaman under the influence of alcohol entered the control room and opened fire with an SA80 assault rifle, killing one officer and wounding another. As a result, Astute only entered service in May of this year – the same month when Artful was launched.

In contrast, Artful as had a fairly quiet time of things. The 7,400 tonne (8,157 ton) boat’s maiden dive took place at BAE’s Ramsden Dock next to the facility where she was constructed. On board were 22 Royal Navy submariners, and about 60 engineers and technicians.

The idea was to confirm the stability of the boat by measuring its hydrodynamics profile, weight distribution profile, and other factors using what’s called a "trim and incline test." In this, four trolleys of lead weights weighing 16 tonnes (17.6 tons) altogether are placed inside the hull and rolled up and down the deck while engineers took measurements to within a millimeter’s tolerance.

The goal is to make sure that Artful floats with such stability that the Captain will be able to balance her perfectly by filling the ballast tanks until she has neutral buoyancy. That is, the sub neither rises, nor sinks. Once that’s done, filling the “Q tank” will allow the boat to descend as easily as a lift.

According to BAE, the dock where the test was carried has a dive hole constructed beneath it to provide 25 m (82 ft) of depth. This can’t cover an A boat completely from bridge to keel, but it was still plenty deep as Artful descended to 15 m (49 ft). If something had gone wrong, it could have sparked a full-blown rescue operation with all the dangers that involves.

Overall, the crew and engineers spent seven hours submerged over a two day period. Meanwhile, the crew tried out Artful’s sonar, navigation and optical systems. According to BAE, the test was successful, opening the way for Artful to undertake sea trials over the next year as she moves towards commissioning.

Artful is the third of the class after Astute and Ambush, which are currently in service, and will be followed by Audacious, Anson, Agamemnon, and a yet-unnamed seventh boat. The £1 billion (US$1.6 billion) attack submarine is larger than the old Trafalgar class boats that it replaces, but requires a smaller crew.

Astute is powered by a Rolls-Royce PWR2 nuclear reactor that never needs refueling for the life of the boat, which isn't even designed to carry out such an operation. This gives the vessel an unlimited range that is only restricted by the need to carry enough food for the complement of 98 officers and enlisted. It's armed with Tomahawk missiles and Spearfish torpedoes, and is equipped with an Atlas DESO 25 echosounder and the Thales Sonar 2076 sonar suite, which the RN bills as the most powerful in the service. In addition, there are two Thales optronic masts which, unlike conventional periscopes, have no direct optics. These transmit directly to a screen, so there’s no need for the periscope mast to penetrate the pressure hull.

“It was exciting and rewarding to be the first person to dive HMS Artful – it’s a significant milestone towards her joining the Fleet,” says Commander Scott Bower, Artful’s Commanding Officer. “There is a real sense of expectancy surrounding the boat now as she moves ever closer to exit Barrow and sea trials.”

The video below shows a timelapse view of Artful’s dive.

Source: BAE Systems

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