The Amphibious Assault Hovercraft – British innovation at its best ?

Royal-Marines-2400TD-Hovercraft-in-Norway

We have had lots of discussions recently on politics, SDSR etc, but I have used the debate in the blogosphere about the cancelling of the USMC Expeditionary Fighting Vehicle (EFV) programme as an excuse to return to a “shiny kit” type of article!

The cancelling of EFV has had a lot of impact on the USN / USMC community. There has been much discussion about whether the basic concept of operations needs to be revised, whether or not storming a beach in an armoured vehicle is even do-able against ‘near peer’ enemies, whether the LCAC is vulnerable, whether the MV22 is good enough at what it’s supposed to do, whether the LPD 17 class is too expensive etc.

You can visit Solomon’s SNAFU blog, or Information Dissemination, or take a quick peek at this USNI blog post to get the flavour of the conversation.

Remember though, the EFV was built to a set of requirements – requirements that many would say were simply too much. The CONOPS was for USN amphibious to stay over the visual / radar horizon, and so the EFV had to be fast on the water to cover the distance to shore (25nm) fast enough to cut down the period of vulnerability. Once ashore it had to be better armed and protected than its predecessor (the venerable AAV7), include protection against big IED’s and have land mobility to allow it to keep up with M1A1 MBT’s – is there any wonder it ended up costing so much it would simply have swallowed up too much of the USMC’s budget.

The right tool for the right job

My initial thought was that it would be better to stick with horses for courses. Rapid ship to shore movement by hovercraft in the shape of LCAC (and its improved successor) or alternatives such as PACSAT and L-CAT type vessels, plus armoured vehicles that may be amphibious, but are designed primarily for protection and land mobility. Many such armoured vehicles already exist, both wheeled and tracked, and indeed the USMC also has a requirement for a new APC.

However, this leaves a requirement for a fast amphibious vehicle to get Marines ‘feet dry’ in the face of enemy fire. This is where my ‘modest proposal’ for an assault hovercraft that is a little more ‘souped up’ than the RM’s current type (the 2400TD) comes in. (By the way, why don’t these have an RWS instead of an open “freeze yer boys off” MG mount ?)

I won’t re-hash the fact that the hovercraft is an excellent British invention, or that we had the amazing Vosper Thorneycroft VT2well before the Yanks were thinking about JEFF-A and JEFF-B, I will stress though that in the shape of Griffon Hoverworks, we have probably the biggest manufacturer of hovercraft in the world (at least in terms of a number of customers, if not in terms of the sheer volume of vehicles delivered).

The biggest purely military craft that Griffon Hoverworkproduce is the 8100TD, which is in service with Sweden and a number of other countries. The Swedish variants have some ballistic protection (wheelhouse armoured against 7.62mm ball), and with a payload of 12 tonnes can carry a BVS10 type vehicle internally. It has a length of 21.3 meters by 11 meters in the beam and can do 45 knots fully loaded. See this page for more details. This is only slightly longer, but substantially broader than the LCVP Mk5 which can carry 35 Marines at up to 25 knots (15.5 m x 4.3 m).

The Modest Proposal

I would suggest an armed and armoured version of the 8100TD might make a pretty good assault hovercraft, so based on the fact that an RM Bootneck with a full Bergen and lots of kit for an “extended stay’ somewhere might tip the scales at up to 150kg, but if only tricked out in fighting order for the initial assault that might drop to 100kg each, I reckon we get between 40 to 60 troops onboard if we cut our payload to 6 tonnes.

For our 6 tonnes of additional kit, I would pick and choose from systems developed for helicopters, and systems developed for armoured vehicles. So for example helicopter-style night vision compatible avionics and displays would take over in the cockpit, which might include both aluminium armour, but also lightweight boron or composite armour developed for aircraft applications. Certainly, thick bulletproof glass as used in MRAP’s would be required for the windscreen and windows of the control cabin/cockpit.

Just as an example an STK dual-weapon RWS with 7.62mm MG and 40mm GMG comes in at 350 kg including ammo, and includes daylight and thermal imaging systems. If take an active protection radar sensor suite designed for armoured vehicles and add the attendant anti-missile system, we might add 50 kg in antennas and I will use the MetalStorm Redback as an example of the anti-missile launcher, as these weigh 70 kg each. I can’t find any weights for a loaded AN/ALE40 chaff and flare dispenser, but I can’t see them being more than 30kg each?

We have used 850kg so far. Perhaps with ESM and laser warning antenna sets we might be up to a tonne, which leaves us 5 more to play with. Perhaps 500 kg might be used on the Textron TRAPS “anti-RPG airbag” system (shown below) to give a second layer of defence against incoming threats?

So let’s say conservatively we have 4 tonnes with which to provide armour protection up to 7.62mm and artillery/mortar shrapnel for the main cabin, propulsion fan shrouds and enhanced protection (12.7mm AP ?) for the wheelhouse.

1 – Wheelhouse repositioned to the centre, with two hydraulic ramps, 1 on either side for troop egress.

2 – port and starboard RWS

3 – Port and starboard forward smoke grenade dischargers

4 – Port and starboard Redback 40mm weapons system as part of anti-RPG / anti-missile system.

5 – wide sliding side doors – both for troop egress or for helicopter-style machine gun mounts

6 – Port and starboard AN/ALE 40 chaff and flare dispensers.

Back to the context of an alternative to a hydroplaning amphibious armoured vehicle. The 8100 Armoured Assault can deposit 60 Marines feet dry after running in from over the horizon at well over 45 knots, jinking and manoeuvring as only a hovercraft can at that speed. With a full threat detection kit, it can do its best to avoid being hit on the run into the beach, flying over mines in shallow waters and on the beach.

Closer to the enemy it can put down suppressing fire with 40mm grenade launchers (with air bursting munitions if required) and possibly up to 4 x 12.7mm MG’s. Active protection systems provide close-in defence against RPG’s and guided anti-tank missiles. 2 such vehicles can deploy a company of 120 heavily armed Marines within minutes, clearing out enemy snipers or RPG / MG and mortar teams waiting to ambush the unprotected LCAC coming in the next wave. Such a vehicle would obviously have other littoral and riverine uses.

Of course, as it has been pointed out in the USNI blog posting I linked to at the beginning of this article, hovercraft require extra wet dock space, whereas AAV7 / EFV or amphibious APC’s take up vehicle space on the cargo decks, and unfortunately the 8100TD is not that much smaller than an LCAC (26.4m x 14.3m). Having said that, lots of commentators have suggested the USN should be buying more, cheaper Schelde Enforcer type amphibious rather than gold plated LPD17’s……..

How about 6 for the RM and we could ship them to trouble zones on a hired merchant?

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