Original URL: https://www.theregister.co.uk/2010/02/26/blightys_seal_minisub/

US Navy SEALs' new airlock minisub - made in Blighty

Brit knowhow cracks 'exploding iPod' battery-inferno snag

By Lewis Page

Posted in Science, 26th February 2010 12:57 GMT

A groundbreaking new miniature submarine in use by the US Navy's secretive, elite frogman-commando special operations force was actually designed and built in old Blighty, the Reg can reveal.

We reported first on the S301 mini-sub two weeks ago, noting from federal documents that the famous US Navy SEALs had leased a demonstration model for "doctrinal, operational, and organizational purposes". This was followed up last week by the Honolulu Advertiser, which had spoken to Submergence Group, the American firm listed by the US government as provider of the S301.

It emerged that the S301 - now in trials with the SEALs in Hawaii - had cost just $10m to develop, which contrasted especially well with the $885m+ spent on the ill-fated Advanced SEAL Delivery System (ASDS).

The S301 at its makers in Plymouth. Credit: MSubs

The stylish ride for today's more discerning frogman-commando. Needs to come in black, though.

The ASDS, from US defence behemoth Northrop Grumman, had been intended to supersede the SEALs' current Mark 8 Mod 1 minisubs, which are carried in a "Dry Deck Shelter" (DDS) airlock docking bay fitted to a full-sized US Navy nuclear submarine - either a normal attack boat or an Ohio-class dedicated Stingray-style special-ops mothership. The Ohios, nuclear missile subs retired from their old job under arms-reduction treaties, have space aboard for a large force of SEALs and pack a powerful armament of conventional-warhead cruise missiles for precision shore bombardment.

The trouble with the present Mark 8 minisubs is that their interiors are open to the sea and SEALs riding in them for long periods can be so chilled by the cold ocean as to be unable to carry out their mission once they are dropped off.

Hence the ASDS, a bigger battery sub with a dry interior, which was to replace the deck hangar and dock with the mother sub directly. It had its own airlock, and so would be able to carry a team of frogmen to work in comfort, locking them out into the sea once it was close to the target.

But the ASDS was dogged by technical snags and cost overruns: it tended to get damaged if the mothership sub went at all fast, and its battery system, we gather, was subject to "thermal runaway". The ASDS programme finally expired altogther when the prototype boat was gutted by fire while stored ashore in Hawaii.

Plymouth-built S301 brings the men in black rubber in from the cold

An SDV minisub with mothership

Mobile parking facilities available.

It had been thought that the SEALs would content themselves with a somewhat modernised wet Mark 8-style minisub, the proposed Shallow Water Combat Submersible: but then news emerged of the S301. Following up on our original report, the Reg has found that in fact the S301 was not produced in America by Submergence Group: it was actually designed and built for Submergence here in the UK by Plymouth firm Marlin Submarines (aka MSubs), in which Submergence owns a substantial stake.

We spoke to MSubs' Paul Moorhouse this week, who confirmed that the S301 can carry two pilots and six frogmen in the dry, and can lock out the passengers in one cycle. Better still, it is of a size to fit in existing US Navy DDS docking bay/hangars aboard mother submarines - the necessary sliding trolley is being built for tests. In effect it solves all the problems the expensive ASDS was designed to solve, for far less money.

"I do feel sorry for Northrop, though," says Moorhouse. "They took a lot of criticism over the ASDS, but the main problem was the battery and that wasn't from Northrop. Anyone can have problems with the new battery technologies - look at all these exploding iPods and laptops and so on. It will take time to eliminate this kind of thing."

The new generation of submarines, like the latest electric cars, are seeking to replace the well-understood but low capacity batteries of old with newer technologies such as lithium-ion. Problems with these are rarely worse than embarrassing in a gadget, but a battery intended to power a car or the still bigger unit needed for a mini-sub can be a serious fire and explosion risk.

Moorhouse is confident, however, that the S301 won't suffer from runaway battery overheating of the sort which did for the ASDS.

The British Special Boat Service (SBS, the maritime counterpart of the SAS) are known to possess a single US-style dry hangar which has been fitted at times to Royal Navy nuclear subs. The SBS also have some Mark 8 wet minisubs, too.

Would the MoD like to buy some? 'No, all their money has to go on keeping BAE Systems alive'

This should mean that the S301 could be used by British frogmen, too, offering the same dry ride in to a landing or a maritime target. We asked Moorhouse if he'd had any interest from the Ministry of Defence.

"No," he said. "They're wedded to the likes of BAE [Systems]. All the MoD's money has to go on keeping them alive. Don't get me wrong - we've had stong interest from the actual services, but they seem to be totally powerless. It's a sad thing."

Funnily enough one of the SBS' more recent acquisitions is known to have been a version of BAE Systems' Talisman unmanned submarine.

Even so, we suggested, it's nice to see British engineering solving a problem that mighty Northrop had stubbed its toe on, and potentially winning a nice bit of export business.

"It's the sort of thing we're good at here [in the UK], solving these one-off little problems," said Moorhouse.

"Frankly this is the same kind of thing that gets done every single year by every race-car team," he added, alluding to Blighty's famous "Motorsport Valley" where most of the world's motor racing titans have their technical headquarters. Motorsport delivers benefit to the UK economy on the same order as the entire ordinary car-making sector - and unlike the ordinary car factories, requires very little in the way of government help.

"Compared to those guys we're rather watered down," says Moorhouse, modestly.

View through the S301's nose port underwater. Credit: MSubs

Now, somewhere round here there should be an oil rig full of terrorists.


Even so, we here on the Reg defence desk would argue that MSubs is the kind of company that the MoD might consider spending our money on, rather than bloated inefficient monoliths like BAE. Genuinely innovative firms who can deliver what nobody else can are a much better investment than pouring taxpayers' cash into BAE to reinvent other people's wheels.

At any rate, it's a nice success story to round off the week with - and perhaps a further illustration of just why British engineering and manufacturing is so far from dead, and of the type of jobs we should nationally be looking to do. ®