Thread by @JonHawkes275

Expeditionary Fighting Vehicle (EFV) was an attempt to do something truly remarkable and failed horribly. But always a cracker to revisit and look at what was almost achieved when someone left the USMC unattended and they dared to dream #miltwitter #tanktwitter #usmc #EFV

EFV has a long and confused history under several earlier guises including the Advanced Amphibious Assault Vehicle (AAAV) but in essence from the 1970s had been seeking to find a modern high speed replacement for the venerable AAV-7A1 family of amphibious assault vehicles

The original requirements were, in honesty, just mad. 3 crew & 17(!) dismounts, 30mm stabilised turret, water speed of >25kts and a range of 400km (though notional mission was 46km swim over the horizon). On land, peer mobility to an M1A1 and 550 km range with high survivability

Two variants would be procured – EVP-P1 (APC), EVP-C1 (Command) with potential to open into a family of variants in time, including mortar carriers, MLRS launchers, self-propelled artillery and possible larger calibre direct fire systems

General Dynamics won design lead for the programme and set up General Dynamics Amphibious Systems (GDAS) to do the work in Woodbridge, Virginia and by 1998 was building the first prototype under the latest contract award, worth USD712m alone

At this point, the USMC planned for LRIP from 2005, FRP in 2008 and final delivery of the 1,025th EFV in 2018 for a total programme cost of around USD8.5bn. Price wise, they were looking to be around USD6m each, similar to an M1 tank of the time

Most amphibious AFV are very slow when in the water. Propulsion little more than the tracks or wheels spinning forlornly, maybe an impeller or prop to help the least hydrodynamic shape possible bludgeon its way through the water

Not so for EFV. Transformation to water mode was remarkable. A gigantic bow plane extends, hydrodynamic roadwheels retract followed by the composite rubber tracks. Chine flaps meet with skirts to seal off the entire track area. A rear transom flap lowers bit.ly/3t5aBfW

Once configured for water running, which as the video showed was fairly swift, twin waterjets fired up at the rear and pushed it into a semi-planing profile allowing up to 25 kts. Its quite a monster when up and running, as you can see in this video: shorturl.at/ciGN1

Doing that isn’t simple though. The MT883 engine uprates via twin turbos for water movement, rising from 865hp on land to 2,750 hp afloat. Twin Honeywell water jets each pushed 3,100 litres of water a second to keep it moving forward

So why did it fail, given you’ve seen videos of some of the 19 prototypes in action seemingly doing exactly what they needed to? Broadly - cost, technical complexity/reliability and changing priorities

You cant understate how monstrously demanding an engineering challenge this was. To get survivability at light weight, balanced for semi-planing afloat meant every technical change cascaded into design spirals to adjust other materials & systems to rebalance the veh, constantly

By the 2000s, it was in a bad way. It worked, but there were big issues. Quoting 2002 DOT&E trials report in this pic, it was dangerously loud, hot, filled with gas from the cannon which was also proving inaccurate and unreliable. Mobility was poor and reliability awful off road

That internal layout continued to be a big issue – the required 17 dismounts would realistically be 14 at best, getting in and out was very slow and any crew served weapons made the inside prohibitively cramped with the overall capacity would be at least 25% less than the AAV7

Four years later and DOT&E 2006 report isn’t much better. The vehicle rarely performed end to end test missions without major breakdowns, reliability and availability were well below requirements and the maintenance burden was onerous

Importantly, it couldn’t reliably plane on water. Despite removal of 2,000lbs of armour before the test, EFV could not get on plane when combat-loaded unless drivers accelerated without steering which caused large unpredictable turns in the water, “an unsafe condition for combat”

Another 4 yrs and DOT&E 2010 still not impressed. Riverine test showed normal levels of debris blocked radiator, overheating engine, and damaged water jets. They were hopeful they might manage 22 hours between major failures but were still struggling to get on plane

With Afghan & Iraq well established and the IED threat showing the huge danger to legacy AAV7 and billions of dollars pouring into MRAPs, EFV was mandated applique underbody armour kits for ashore operations, which were to have knock on impacts to many performance aspects

Price was also becoming a big problem. Early aspiration for c. USD6m each was now USD24m each and still climbing. At the time that was around 7x the cost a Bradley, and 4x the cost of an M1. This was driven by a lot of advanced materials and the ceaseless engineering challenges

Consequently the original 1,025 EFVs was now down to 573, and there were concerns that the high cost of the EFV could consume as much as 90% of the USMCs ground equipment budget for the coming years, and it was already overfilled with kit for OEF/OIF

It took some time to truly die, but eventually in January 2011 the programme was killed off formally, and the technological marvel (even if flawed) came to an end, another saga in the billions of dollars spent on kit that never sees US service.

EFV ultimately was exemplary of the era where the US was dreaming big. FCS and EFV were monster programmes pushing boundaries of technical possibility and even almost 20 years later we have no sign of much of what they were physically demonstrating back then being viable soon

The USMC has not given up though, while the conventional 8x8 ACV, based on the IVECO SUPERAV is entering service under the same named programme, ACV Phase 2 will seek to try EFV again with a notional target of 2035

Meanwhile the research has not been ignored. Japan is developing its own monstrous amphibious vehicle, which is heavily informed on a formal basis by data from the US under the research of the Next Generation Amphibious Technology (NGAT) programme

Directly following on from EFV research, NGAT is a very similar requirement for a high water speed, high capacity amphibious AFV. They’ve pushed the engine up to 3,000hp as they believe this the minimum for getting onto reefs from deep water, a very difficult mobility challenge

A lot of the work so far has been sorting that engine with scale model testing of a notional vehicle in the next few years with full scale prototypes around the end of the decade.

Thereafter who knows, we may see an all-new super EFV in 2030s or 2040s again. Fingers crossed. /end