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Landing Craft Capability Advances and Implications for the Force Mix

Following the protracted and costly land campaigns of the early 21st Century, national security

strategies are refocusing upon the maritime domain as their preferred base from which to generate

and sustain required effects. The littoral remains an important and challenging part of this domain,

not least when projecting power ashore during an amphibious operation. Both contemporary and

emerging threats have made this seam between land and sea even more contested, reflected in the

doctrinal push to position sea bases well beyond the horizon. For example, the USMC Expeditionary

Force 21 Concept1 refers to advance force/shaping operations being launched at ranges from 65+

Nautical Miles (NM), and surface assault waves with ranges between 30 – 12 NM for transit to the

beach2. Operating at such range provides increased protection to the amphibious task force and a

greater degree of uncertainty for any adversary; they will struggle to predict both where and when

beaches may be crossed to manoeuvre towards a number of potential objectives. Conversely, it

creates a significant problem for the amphibious force in generating the required tempo of the

surface assault, providing the necessary offload volume in time to complement and support the

aviation assault component. To meet this challenge, amphibious forces should embrace recent (and

affordable) advances in surface connector technology to decrease both transit times and craft

vulnerability.

The Drive to Launch at Range

Threats to an Amphibious Task Group (ATG) operating close to the land are varied and considerable.

Fast aircraft and guided missiles will use terrain masking when approaching over land; the closer the

ATG to the shore, the shorter it’s response times. The ranges of any enemy shore based artillery

(and their associated surveillance mechanisms) must be considered when selecting an Amphibious

Operating Area. Platforms tasked with protecting the ATG will need maximum manoeuvre space

and a high ship speed to ensure the effectiveness of decoy measures. Threats from Fast Inshore

Attack Craft (FIAC), (whether deployed as an asymmetric (state operated) or irregular (terrorist

operated) means) is mitigated by range, allowing earlier tracking, identification and selective action.

The greater the range from FIAC operating bases, with a potentially increased sea state further from

shore, makes such craft less potent. Below the waves it can be argued that shallower water reduces

the conventional submarine threat (although uncertain hydrography bites both ways) but small SSK,

mini-submarines and even divers could devastate an ATG in confined and shallow waters. Mine

laying options increase with proximity to the coastline, as does the vulnerability of mine counter-

measure operations. An ATG operating at range will allow an early warning of threats, platform

manoeuvrability, full operating freedom of weapons and counter measures and a reduced

vulnerability to mines; it is also increasingly difficult to detect and track.

The Transfer of Risk from Platforms to Connectors

Whilst many of the capabilities available to a defender are not new (at least in concept) the modern

amphibious force’s appetite for risk has reduced, reflecting the decrease in the number of assets

1. (USMC 2014) 2. (USMC presentation at Sea-Air-Space 2014)

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available and the consequences of the loss of even one major platform. Carrier strike and

amphibious platforms may need to group even closer in order to share some or all of the anti-air,

anti-surface and anti-under-water capability available. In the same way that a modern amphibious

force will not choose to select a landing beach it knows will be heavily opposed, it will also strive to

minimise the threats to the launch and sustainment of the operation.

In effect, these littoral risks are transferred to the aviation and surface connectors. Whilst critical as

a component, they are more numerous, detection and targeting is more difficult and individual

losses are more bearable. The increased range to the amphibious objectives clearly affects the

tempo for both aviation and surface assault waves, critical for exploiting the advantage of

operational surprise, but the latter faces a disproportionately negative impact. Despite the wider use

of heavy lift helicopters (e.g. MH53, CH47) within the amphibious inventory, and the development of

such capabilities as the tilt rotor MV-22 Osprey, their maximum payload capability is between 8 - 15

tons3, below the weight of many modern fighting and logistic vehicles. The need for greater anti-

mine protection has seen these vehicle weights increase. The utility and reliance on these vehicles,

alongside the inherent flexibility of delivering force by both sea and air, means that surface

manoeuvre remains a fundamental element of projecting power from the sea.

The Surface Connector Challenge

The performance of the heavy Landing Craft Air Cushion (LCAC) continues to provide a very real

solution to the issue of covering distance quickly; with the full weight load of a Main Battle Tank

(MBT) it has a planning speed4 of 40 knots and can reach a beach (and beyond) at 30 NM from its

launch in 45 minutes5. Their ability to cross 80% of the globe’s coastlines6 and operate into the

hinterland over mud, marsh, ice and sand make them a highly attractive asset. However, they are

comparatively expensive to purchase, run, maintain and train to operate, and numbers carried

within an ATG are limited. Their wide beam restricts the number stowed in the amphibious platform

dock, being broadly twice the width of an LCU (UK MK10) that can lift the same MBT load.

Fig 1 - US LCAC

3. (Bell n.d.) (Placeholder1) 4. Planning Speed – the operating speed used to gauge journey times for planning purposes. 5. (Textron Marine & Land Systems 2011) 6. (ibid)

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There are indications of concern within the most capable amphibious force in the world, the United

States Navy (USN) and the United States Marine Corps (USMC), that their current surface connector

capacity does not close the gap between doctrinal aspiration and operational reality7. Despite the

impressive speed of the LCAC, their finite numbers carried within an ATG and the extended

operating range means that the build-up of heavy equipment shore side is not fast enough. The fact

that the USMC have abandoned their extensive and expensive efforts to develop an Expeditionary

Fighting Vehicle that could triple the afloat speeds of the current Amphibious Assault Vehicle

(between 8- 12 knots)8, exacerbates this issue further. The Mobile Landing Platform concept9,

providing more LCACs and an increased operating capacity, will undoubtedly mitigate some of this

shortfall. However, the transition of Ship Life Extension Programme (SLEP) LCACs to the new LCAC-

100 fleet over the next 20 years may see a decline in availability before the new connector fleet is

fully in place.10

The challenge of operating well beyond the horizon is even more of an issue for those amphibious

forces without heavy LCAC to deliver armour, vehicles and combat supplies to the beach. The speed

of conventional displacement landing craft (utility) has changed little since their development from

World War II, with planning speeds varying from approximately 14 knots for lighter loads (60 ton

tank and below) to 9-10 knots (72 ton tank). Originally planned to operate within less than 5 NM of

the beach, the extended range of declared sea bases does not allow the required tempo of

amphibious flow. Whilst first waves can be launched to ensure arrival at H-Hour, it is the interval

between the second, third and on stream waves that are so important to the Commander Land

Forces, to ensure consolidation on the objectives before any counter attack. Slower landing craft

become more exposed and vulnerable to enemy action on theses longer transits to and from the

beach, with crew times extended and embarked troops fatigued.

Modern Alternatives to the LCAC?

However, recent developments offer a real alternative to non-displacement surface connectors. The

French company CNIM have designed the L-CAT 100, a catamaran hulled landing craft used by the

French Navy since 2011, with a well deck mounted on rams, that when raised clear of the water is

able to operate at speeds of up to 25 knots, depending on the load.11 When the ramp is lowered the

craft can operate in shallow water towards the beach, or even offload at a jetty.

7. (USMC Surface Connector Summit 2014) 8. (LVTP7 Landing Vehicle, Tracked 2014) 9. (The US Navy’s Mobile Landing Platform Ships (MLP) 2015) 10. (Commander Naval Sea Systems Command | 1333 Isaac Hull Avenue, SE | Washington Navy Yard, DC 20376-1080 | 202-781-0000 | n.d.) 11. (IHS Janes 2015)

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Fig 2. CNIM L-CAT 100

A more traditionally robust design, but with a step change in capability, is BMT’s Fast Landing Craft

(FLC), the Caimen® 90. A shaped monohull with BMT’s Tribow design and three powerful waterjets,

it is broadly the same size as a UK Mk 10 LCU. It has been tank tested to be able to deliver a 90 ton

load at 22 knots, and 40 knots when unloaded12. Notably this performance is only marginally

impacted by sea state, with a speed drop of only 1 knot at sea state 4. The same sea state, with

wave heights between 1.25 – 2.5 metres, will have a far more detrimental impact on a loaded LCAC’s

operating speed13.

Fig 3. BMT Caimen®90 Fast Landing Craft

There are other penalties associated with operating LCACs. High daily and routine maintenance

rates reflect both the complexity and cost of a gas turbine against a diesel engine, and the

vulnerability of some LCAC components such as the skirt. The twin gas turbine engines have a high

fuel use rate, at approximately 1000 US gallons per hour (with payload) to transit 40 NM14.

12. (BMT DSL 2014) 13. (Textron Marine & Land Systems 2011) 14. (Landing Craft, Air Cushion (LCAC) 2014)

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Compare this to a UK LCU Mk 10, which carries a similar payload weight. In the same hour it will

consume approximately 70 US gallons - but will only travel 9-10 NM15. To deliver the same payload

the same distance, the LCU will use less than a third of the LCACs fuel – but take over four times as

long to complete. The BMT Fast Landing Craft will straddle these rates, burning 315 US gallons an

hour, using 525 US gallons to deliver the payload 40 NM (but taking 40 minutes longer)16.

Surface Assault Performance Comparisons

The following tables compare broad speed and estimated fuel consumption data from the US LCAC,

the Tribow FLC, the L-CAT 100 and a UK LCU Mk 10, showing time taken to deliver combat loads to

beaches at 12 NM (fig. 4) and 30 NM (fig 5). A common offload time of 5 mins, and a reload time of

10 minutes, has been added to each assault wave interval period.

Planning Speed

(knots) 1

st

wave

on

beach

2nd

wave

on beach 3

rd

wave

on beach Estimate of

total fuel used

(US Gallons)

LCAC (H) 40 18 mins 69 mins 120 mins 2,000

FLC 22 out/ 40 return 33 mins 99 mins 165 mins 872

LCAT - 100 18 out/ 25 return 40 mins 123 mins 206 mins 1,496

LCU Mk 10 10 72 mins 231 mins 390 mins 455

Fig. 4 - Journey times and fuel usage - 12 NM to beach

Planning Speed

(knots) 1

st

wave

on beach 2

nd

wave

on beach 3

rd

wave

on beach Estimate of total

fuel used (US

Gallons) LCAC (H) 40 45 mins 150 mins 255 mins 4,250

FLC 22 out/ 40 return 82 mins 224 mins 366 mins 1,811

LCAT- 100 18 out/ 25 return 100 mins 287 mins 474 mins 3, 440

LCU Mk 10 10 180 mins 555 mins 930 mins 1,085

Fig. 5 – Journey times and fuel usage - 30 NM to beach

Connector Stowage

Whilst payload and speed remain important connector capabilities, the number able to be carried to

the sea base will have a significant effect on the volume and tempo of offload. Fig. 6 shows the

comparative dock ‘footprints’ of the LCAC, L-CAT 100 and FLC, using a single MBT as the common

15. Data from BMT DSL records. 16. Ibid.

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point of visual reference.

Fig. 7 shows two FLC superimposed over the LCAC profile – their combined beams of 2 x 25.2 feet

(7.7M) at 50.4 feet (15.4M) being marginally broader than the single beam of the LCAC at 48 feet

Fig. 7 shows two

Fig. 6 – Comparative FLC, LCAC and L-CAT

footprints

Fig. 7 – Footprints of 2 x FLC superimposed

over 1 x LCAC

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(14.6M). It should be possible for two FLC to be accommodated in the same dock space as a single

LCAC, although issues such as dock dividing walls, and the current width of docks would need to be

addressed. For new designs there would be minimal impact on the whole platform design. For this

paper this premise is followed to illustrate the potential gains of an increase in numbers of fast

surface connectors able to be carried by an ATG

Connector Fleet Comparisons

A relatively simple scenario demonstrates this valuable point. A Landing Helicopter Dock (LHD) such

as the USA Wasp Class can carry 3 x LCAC17, or in this assumption, 6 x FLC. A Landing Platform Dock

(LPD) such as the USA San Antonia Class can carry 2 x LCAC18, or in this assumption 4 x FLC. A

comparison is made over the time to deliver a representative amphibious Surface Assault Echelon

(SAE) by respective connector fleets to the shore at 30 NM range. For this example the combat

echelon from the Battalion Landing Team (BLT) represents two mechanised infantry companies with

a troop of tanks in support. In a simplified payload requirement, excluding beach and engineer

enablers, the vehicle lift is shown in Fig. 8.

17. (IHS Janes 2015) 18. Ibid

Fig. 8 Representative surface assault echelon lift requirement

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The total lift, or payload, of each craft is shown at fig. 9:

The table at Fig 10. shows the payload and delivery times (cumulative) from when the first waves

leave the assault platforms.

Craft Type Wave 1 on beach Wave 2 on beach Observation

5 x LCAC 45 Mins

2 x MBT

12 x LAV

6 x HMMWV

150 Mins

2 x MBT

12 x LAV

6 x HMMWV

BLT SAE short of 8 x HMMVW by

delivery of 2nd wave.

10 x FLC 82 Mins

4 x MBT

12 x LAV

12 x HMMWV

224 Mins

12 x LAV

8 x HMMWV

BLT SAE delivered and with extra

space in 2nd wave for 5 x MBT, or 20

x LAV/ HMMWV

Fig. 9 Single landing craft payloads

Fig. 10 Comparative connector fleet payload and journey times (@ 30NM)

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This theoretical scenario shows the effect of a greater number of (smaller) connectors. Despite

being slower craft (when loaded), the greater total payload per wave of a FLC fleet allows the whole

of the surface assault echelon to be delivered to the beach by the second wave and have extra space

for 20 LAV/ HMMWV or 5 x MBT. Despite the LCAC fleet’s superior speed and individual payload, its

lower numbers mean that the whole surface assault echelon will not be delivered until the third

wave; in this case at 255 minutes, 31 minutes behind the FLC fleet. This example does not account

for craft redundancy; degradation of availability, by mechanical or enemy means, should favour the

larger FLC fleet.

However, the most significant results are generated when the LCAC and FLC fleets are mixed:

Optimal Connector Fleet Mixes

Such mixes exploit the advantages of both types of craft: smaller, more numerous FLC that can carry

compact heavy loads, with bigger, faster LCACs that can carry greater volume across any beach and

beyond.

A fleet mix, able to be stowed in the LPD and LHD, of 2 x LCAC + 6 x FLC will generate a total single

lift of 4 x MBT, 20 x LAV, 10 x HMMVW – only 4 x LAV and 10 x HMMVW short of the full combat

echelon. If speed and access is a greater priority to payload, a 3 x LCAC + 4 x FLC fleet mix will

generate a total single lift of 4 x MBT, 12 x LAV, 6 x HMMVW.

It is interesting to note the relative unit purchase prices of such connector fleets. An estimate of the

cost of an FLC has been generated by BMT and independently endorsed by a number of industry and

shipbuilding partners. The cost of an LCAC has been taken from publically released programme

information. However as each nation has unique requirements, purchasing and procurement

practices, the values presented should be taken as indicative to show the relative cost of each

platform type. In this illustration the following planning assumptions are made:

1 x LCAC costs US$47.6M19

1 x FLC costs US$10M20

This leads to the following fleet costs:

5 x LCAC = US$ 238M

10 x FLC = US$ 100M

2 x LCAC + 6 x FLC = US$ 155M

3 x LCAC + 4 x FLC = US$ 183M

No comparison of through life costs has been made, however this will be affected by fuel, manning,

maintenance and training regimes and connector numbers.

19. (Marine Corps Warfighting Lab assesses potential landing craft replacement 2014 ) 20. From BMT assessment, endorsed by separate industry estimates

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Wider Roles

There are some roles that are far better suited to the displacement landing craft than a hovercraft,

exploiting its ability to operate for extended periods independently, or as part of a boat group

temporarily detached from its parent platforms. The increased speed of the craft and ability to carry

different combat systems means they could be used in the fleet/force protection role. The ability to

patrol, loiter, moor, anchor and beach, all at distant range, allows the LCU to act as a floating

command post/mother craft for reconnaissance tasks, boarding operations or riverine patrols, with

smaller assault craft using it as refuelling, maintenance and accommodation base from which to

operate for days or weeks. Such capabilities can be extended for disaster assistance and

humanitarian relief roles, including logistical and medical support, the movement of plant and heavy

equipment, a diving platform or ferry operations.

Conclusion

Developments in hullform hydrodynamic design have now freed the landing craft utility from its

‘floating skip’ reputation. The step change increase in performance offers a surface connector that

can meet the demands of increased operating range and de-risk this vital link of the amphibious

chain. They provide a compelling alternative to heavy LCACs for those forces that cannot justify the

resources necessary to operate this impressive capability. And for LCAC equipped navies, a fast

landing craft’s heavy payload lift, smaller dock footprint and capacity for wider amphibious roles

provides a complementary capability to operate on similar terms alongside these larger surface

connectors.

Toby Middleton

BSc MA Colonel Royal Marines (Retd)

Head of Business Development - Amphibious Platforms BMT Defence Services Ltd

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Works Cited

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2015).

Commander Naval Sea Systems Command | 1333 Isaac Hull Avenue, SE | Washington Navy Yard, DC

20376-1080 | 202-781-0000 |. PEO Ships Landing Craft Air Cushioned (LCAC) Service Life

Extension Program (SLEP). n.d.

http://www.navsea.navy.mil/teamships/PEOS_LCACSLEP/default.aspx (accessed April 2015).

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—. Country Report - USA- Maritime. Jan 2015. IHS Janes.com (accessed Feb 2015).

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(accessed March 2015).

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Warfighting-Lab-assesses-potential-landing-craft-replacement (accessed Mar 2015).

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capabilities. Slidell, LA: Textron, 2011.

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http://www.defenseindustrydaily.com/The-US-Navys-Mobile-Landing-Platform-Ships-

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USMC. “Expeditionary Force 21.” Expeditionary Force 21. 3. Expeditionary Force 21 Capstone

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ncept.pdf (accessed April 2015).

“USMC Surface Connector Summit.” VA, March 2014.