Tag Archive for: LHD

Navy’s LHDs under the microscope

The Royal Australian Navy’s flagship, HMAS Canberra, has completed trials off the NSW coast to help engineers assess whether its mechanical problems have been caused by a serious design flaw or a less serious issue, such as degraded seals.

The Navy’s two giant Amphibious Assault Ships, also known as Landing Helicopter Docks or LHDs, at 27,000 tonnes, they are the biggest ships ever operated by the RAN. Both have had problems with the two large ‘azimuth pods’ which drive and steer the vessels.

Canberra’s sister ship, HMAS Adelaide, is in dry dock in Sydney’s Garden Island so that it’s pods can be dismantled, examined and undergo routine maintenance. The decision to move the Adelaide into dry dock was made in large part so that bearings in its pods could be thoroughly examined, said Navy chief Vice Admiral Barrett: ‘It’s inconclusive at the moment.’

Instead of having a drive shaft running through the ships from engines to propeller, and a conventional rudder, the LHDs have two electrically driven pods near the stern of the ship, each bearing two forward and aft sets of 4.5 metre propellers. They increase the vessels’ manoeuvrability by swivelling to push or pull them in the required direction. Similar pods are used on many modern cruise ships, allowing them to dock easily with little or no assistance from tugs.

The azimuth pod system makes room at the stern of the vessels for landing craft to enter and leave via a giant well dock which is flooded to launch and recover them. Each ship can carry 1000 troops with all their equipment and a formidable array of armoured vehicles.

The LHDs were built by the Spanish company, Navantia, and their propulsion systems came from Germany’s Siemens. The British firm BAE Systems was the project integrator and prime contractor. All three companies have sent specialists to work through the issues.

The Spanish Armada has one such ship of its own, the Juan Carlos. It is currently due to have one of its pods repaired in Spain, but because of a different issue, apparently relating to a seal and bolts at the point where an azimuth pod meets its hull.

Australian Navy chief Admiral Tim Barrett and the head of maritime systems at Defence’s capability and sustainment group, Rear Admiral Adam Grunsell, said different problems had emerged with the pods on HMAS Canberra and HMAS Adelaide. Oils of different viscosity used in separate parts of each pod were found to have mixed in one of Canberra’s pods, possibly because a seal had failed.

In a pod from HMAS Adelaide, particles believed to be metal fragments were found mixed with oil. The physical examination is intended to find out if the metal came from a bearing wearing excessively, or from another metal part. Until the bearings were thoroughly examined it would not be clear how serious the damage was, Vice Admiral Barrett said, though he said that the amount of particulate matter found in one of HMAS Adelaide’s pods ‘was not catastrophic’.

The Australian ships have already travelled about twice the distance of the Spanish Navy’s vessel. Vice Admiral Barrett said the RAN had operated its two ships within their specifications. ‘We are investigating whether there are differences in how we operate.’ He has been in close contact with the Armada over the issue.

The pods contain sensors to monitor issues such as oil temperature, vibration and bilge level. Some of them were found to be malfunctioning and they’ll be replaced. HMAS Canberra can still operate at cruising speed of around 16 knots.

The two ships were to be stars of the show at the coming Talisman Sabre exercise with the United States and other allies in June, but Vice Admiral Barrett said the Adelaide wasn’t likely to be available in time He hopes the Canberra would take part, but said that other Navy vessels could fill the gap.

With HMAS Adelaide in dry dock the engineers will be able to check if seals have become unseated. They’ll also assess whether the particles found in the oil had been worn off a metal part such as a bearing or a shaft because of a relatively minor problem with a seal, or because of a more serious issue elsewhere in the system. ‘The program is to discount things, to point to whether it’s a bearing issue for instance, and from there we’ll decide whether to change its activity, an operating limit or something along those lines,’ Vice Admiral Barrett said.

Rear Admiral Grunsell said the three companies involved were working very closely with the Navy to find out what was wrong. ‘They want to understand what caused this as well. It may well be something simple or a design issue. ‘

Vice Admiral Barrett said the ships may still have some residual warranty but commercial sensitivities had to be managed. Last October, the ships had a problem with their high voltage cabling systems which was resolved with the help of the manufacturer.

Vice Admiral Barrett said the possibilities were being narrowed down. The answer might be as simple as a seal being pinched when the pod was assembled. ‘We’re slowly working through what it’s not to determine what it is’, he said.

Rear Admiral Adam Grunsell added: ‘It’s a complex array of equipment down there and the purpose of the investigation is to look at every piece of equipment in a disciplined engineering fashion so that we can rule in or rule out contributing factors. It may be a singular cause, or it may be an aggregation of a number of issues’.

The ‘Silver Bullet’ conundrum: naval losses in a world of small fleets

Image courtesy of Flickr user QUOI Media Group.

In the post-Cold War era, western navies have continued to seek the highest levels of technology and capability in an environment of declining defence budgets. This has caused a reduction in overall fleet sizes as unit costs increase, and the creation of ‘silver bullets’ in fleets that rely on a smaller number of more capable platforms. At the same time naval vessels face increasingly lethal and numerous anti-surface weapons. So the costs of losing even one vessel may be more significant than we imagine.

Losing ships is a likely (and therefore expected) part of naval conflict, but losses affect navies of differing sizes to different degrees. Most modern navies haven’t lost a ship to enemy action since World War 2 so they haven’t had to deal with the consequences first-hand in a long time. However, the Falkland Islands war in 1982—one of the few examples of naval conflict in the missile age—provides some interesting insights.

The UK deployed 37 warships (25 surface combatants, six amphibious ships and six submarines) as a part of the taskforce assembled to take back the Falkland Islands, supplemented by auxiliaries and civilian vessels. The Royal Navy (RN) at the time consisted of 92 combat vessels, so 40% of its combat vessels were sent to the South Atlantic. During the conflict the RN lost four combat vessels—two destroyers and two frigates—to Argentine air and missile strikes. Those losses accounted for 16% of its deployed combat strength but only 4% of its overall fleet combat strength. Additionally 11 combat vessels from the task force were damaged, accounting for 30% of its total deployed combat strength and 44% of its deployed surface combatant strength. Keep in mind, the losses inflicted upon the RN came from an Argentine military operating at the edge of its operational range, and using anti-ship missiles (and unguided bombs) that aren’t nearly as accurate as their modern-day counterparts.

If the UK was to deploy a similar task force today—assuming it can deploy a similar percentage of the fleet as it did in 1982—it could assemble a meagre task force of 13 combat vessels from an overall fleet of 32. Assuming losses in the same proportion as 1982, one or two vessels would be sunk and another four damaged, which would leave the task force with only 8 undamaged vessels. In fact, the UK may not be able to conduct such an operation today with such low numbers.

For smaller navies such as the Royal Australian Navy, taking similar losses would be devastating. It’s unlikely that the RAN would unilaterally send a naval task force into a high-end conflict. However running the ruler over the fleet using the percentages noted above is illustrative of the risks that naval capability planners across the board are taking by investing in ‘silver bullets’.

The RAN currently operates 19 combat vessels: two LHDs, three guided missile frigates (FFG), eight helicopter frigates, and six submarines. If the RAN were to deploy a task force of similar proportion to the one sent by the RN to the Falkland Islands, it would likely consist of eight ships. Assuming the same loss rate, the Australian task force would lose one ship outright and 2 or 3 vessels would be damaged, leaving around four or five vessels to continue operations. Those numbers may even be optimistic, as a small task force means there are fewer ships providing defensive cover. That leaves little margin to absorb the loss and achieve objectives.

Applying those loss figures to specific classes of RAN vessels exposes the inherent vulnerability of small navies. If one submarine or FFG is lost, the task force may lose its air or subsurface cover and the RAN would lose at least one-sixth or one-third respectively of the gross total fleet of that platform (and that’s assuming that every vessel is available all of the time). If the LHD is sunk, or just damaged enough to cause its withdrawal, then the task force will no longer have an amphibious capability, likely leading to mission failure, and the RAN has lost half of the amphibious capability provided by the LHDs (plus the personnel, aircraft and equipment on board).

Admittedly, comparing naval capability from the early 1980s to now, and the RN to the RAN, isn’t perfect. Today’s ships are more capable, have improved countermeasures, and are better able to cooperate with supporting capabilities such as airborne surveillance. But anti-surface weaponry is now more lethal, accurate and numerous than it was in 1982; these weapons also have the advantage of being significantly faster and more manoeuvrable than their targets, which makes defending against them more difficult. In a world of small navies where each vessel is incredibly capable and quite expensive, losing just one vessel can undermine the chances of success.

Quantity does have a quality of its own; however there’s a trade-off between numbers and capability that must be met. But that’d require another 800 words…

The LHDs and the rotor-wing option—a pilot’s response

HMS Illustrious is pictured during Exercise Cougar 12 in the Mediterranean Sea.Where H is for helicopter, emphasising the H in LHD is imminent. HMAS Canberra is now due to conduct initial underway deck, embarkation and aviation support trials with ADF ground-support helicopters. In a recent Strategist post Albert Palazzo and Antony Trentini advocated the use of SH-60 Romeo helicopters from the LHDs for anti-submarine warfare, in a new tasking to complement the oft-stated amphibious and humanitarian operations. Their welcome piece expands thinking of the LHDs in a strategic light, but includes yet another ‘swing’ at possible F-35B operations from the LHDs. I hope this follow-up helps add some light to this new strand in ASPI’s LHD discussions.

The LHDs are not LHDs. They’re ‘strategic projection ships’, a clunky term admittedly that doesn’t much help describe their full capabilities. In plain English, they’re better described as multi-role flat-tops. LHD is an obsolescent and single-role label that’s used for easy signage, but does not indicate the possible air-power capabilities Australia has to hand with these ships. Rotary ASW is certainly one of those capabilities, and the ADF already states that the Canberras will be able to support Romeos as well as the ground-support MRH-90, Chinook and Tiger aircraft. But as expert contributors to The Strategist have pointed out, they’re designed to accept fixed-wing aircraft—they’re not solely a ‘rotary-wing’ platform. Read more

Forget the carrier option: an engineer’s response

An aviation boatswain’s mate maneuvers BF-04, front, the U.S. Marine Corps variant of the F-35B Lighting II

Nic Stuart’s piece, ‘Forget the carrier option’, makes a large and important judgment: that politics and defence funding won’t allow the option of deploying F-35Bs on Australia’s LHDs. But in making that case Nic repeats erroneous assumptions that are hindering a true exchange of views. It’s vital that defence reviews are supported with facts—and some of them bear repetition.

First up, the technical facts. F-35B operations from LHDs are feasible. The F-35B is specifically designed not to drive major ship modifications. The LHD wouldn’t need ‘conversion’ to take F-35Bs, although it would require minor modifications, similar to those being applied to the USN ‘Wasp’ class. The flight deck is capable of taking an F-35B. The F-35B won’t require massive changes to the ships’ air-traffic control facilities, assuming that they are already up to operating rotary-wing aircraft day or night in bad weather. It won’t need huge changes to ship structure or facilities.

Those modifications would’nt ‘cost a great deal’, as Nic stated. And to repeat, giving the LHD an ability to operate F-35B doesn’t mean turning it into a ‘mini aircraft carrier’. Read more

LHD and F-35B: the debate opens up

Marine Corps Joint Strike Fighter F-35B on a test flight on the Patuxent River, Maryland.Debate over the possibility of operating F-35B aircraft from the Canberra LHDs has opened up—a good thing. This post offers technical and tactical thoughts to stimulate the debate and challenge recent assertions.

The feasibility of acquiring an F-35B/LHD capability is a key issue. Some assert that it’d be highly complex, take the ships out of service for long periods, cost $500 million, and require decades to achieve. Those assertions massively overstate the problems and ignore a plethora of inconvenient facts.

The Canberras retain the essential capability of the ‘Juan Carlos I’ design, including features that support the F-35B. They have air traffic control facilities for helicopter operations, which would support STOVL, although an additional lighting system may be required for bad weather operations. The F-35B wouldn’t require large ‘specialised’ maintenance facilities to be built into the ship, although adaptation of existing spaces might be required. The Canberras have enough fuel to support F-35Bs, and large weapons magazines. Claims to the contrary are incorrect.

Read more

Aircraft carriers for Australia?

An F-35B Lightning II makes the first vertical landing on a flight deck at sea aboard the amphibious assault ship USS Wasp (LHD 1).Commentators are suggesting Prime Minister Abbott and Defence Minister Johnston haven’t completely discounted the possibility of acquiring the jump-jet version of our future F-35 fighter, and might even be keen on the idea. As a result, friends and colleagues are lining up to rib me for supporting the target of spending 2% GDP on Defence. ‘See what happens when the funding taps open up?’ they chide.

In my defence, I’d argued that Australia requires both sound strategy and adequate funding. Since strategists have to plan for a highly uncertain, and seemingly increasingly threatening, future, it’s generally better to have more capabilities in order to give Government a wider range of options across various credible scenarios. Signalling strategic resolve and weight can also be useful in troubling times. But taking steps to be able to operate jet fighters off our LHDs doesn’t pass the cost-benefit test for me, and could send signals we’d rather not. So while it’ll be useful for the White Paper authors to revisit the case for fixed-wing navy jets in changing strategic circumstances, I’m sceptical they’ll identify strong grounds to proceed. Read more