LR11: the new submersible stalwart?
A boat coming to a halt at sea is one thing. A naval submarine, stranded below the surface, is quite another. Time is of the essence if the crew are to survive.
“A distressed [naval] submarine weighs tens of thousands of tonnes. Even if there was a way to do it, you can’t possibly lift the submarine out all in one piece, and certainly not in time to rescue all the people inside,” says Chris Buckle, Senior Operations Manager and Defence Specialist at Forum Energy Technologies.
The answer is submersible rescue vehicles (SRVs), like the LR11, which can rescue 17 crew per trip from submarines as deep as 600 meters.
Internal view of LR11's rescue hatch and chamber.jpg (Credit: Forum Energy Technologies)
Proven technology trumps the latest technology
Forum Energy Technologies has been in the SRV business for over forty years. The world’s first rescue submarine, created in 1982 by Forum Energy Technologies (then part of the Vickers), was a converted fibreglass submarine. In the 1990s, the team developed the first purpose-built SRV. The LR11 (LR being a nod to Sir Leonard Redshaw, who pioneered British shipbuilding in the 20th century) is the latest SRV.
While the technology used for the SRV’s has changed over time, each new version is not built solely with the newest technology. “These systems are military products that will go down to 600 meters…it has to work first time every time. Nobody wants a completely brand-new system that hasn’t got any proven technology or history,” Buckle explains. That’s not to say there is little evolution. Instead, for each new vehicle, “we take the last design and then develop it. Then we may add other proven technologies – sensors and battery systems [for example].” Among other things, the LR11 can carry more people, go to deeper depths, and travel at a greater speed than its predecessors.
Equally important is that the customer can maintain the SRV. “We’ve got a 24/7 support team, but [the customer] could be in the middle of the sea, three, four, five hours, or even more from land. If [they] need to repair something, and [they’ve] got people trapped in a submarine, they need to be able to do it themselves,” explains Buckle.
From Yorkshire to Vietnam
As with all rescue vehicles, the LR11, which was built for the Vietnam People’s Navy, underwent a series of tests, starting at the Kirkbymoorside facility in Yorkshire, England. “We’ve got a lab test pool built six metres deep and a hyperbaric chamber where we can test [how the SRV performs] under pressure. We [then] went to Newcastle and spent ten days in the harbour to confirm everything,” says Buckle.
The trials didn’t end in the UK. Once the LR11 reached Vietnam, it was subject to further testing. “Because [the SRV] is built under Lloyd’s Register for shipping, we have to do certain sea trials, for example, taking the vehicle to full depth,” Buckle explains. Then there is the connection to a distressed submarine. “On the bottom of the rescue vehicle is an upside-down cone with a seal [on one end, and a hatch to the vehicle on the other]. That seal goes over the hatch of the distressed submarine, then you pull the water out and transfer the people through…we need to test that with the Navy [submarines],” says Buckle. The customer will also run their tests. “We love all that, so we support them during those extra tests,” Buckle adds.
Ultimately, it is hoped that an SRV will never be needed, but if one day it is, the LR11 will be ready.
Read about the engines that power the RNLI here and watch the presentation on the RNLI’s latest lifeboat design on IMarEST TV.