Categories
Cold War US Vehicle

NASA M113 Armored Rescuer

USA, NASA (1960’s – 2015)
Armored Rescuer – 4 Used

From the days of the Mercury space program, the means of evacuating astronauts from a burning or otherwise compromised rocket vexed the National Aeronautics and Space Administration, better known just as ‘NASA’. The problem was to get the astronauts from the rocket and to safety as fast as possible. The standard means chosen was to use a zip-line to get the astronauts from the rocket (or later from the shuttle) to a concrete bunker from where they would be driven to a safe distance.
The nature of the contingency being unique meant a unique solution was required which came in the form of the M113 Armored Personnel Carrier (APC). An armored vehicle would allow rescue crews to get to and from the scene and evacuate astronauts safety regardless of falling debris. At least 4 M113 vehicles were obtained. In 2013, upon the announcement of their retirement, it was confirmed that the 4 new vehicles had been obtained to replace the M113’s. This suggests that just the 4 M113’s had been used by NASA at the Kennedy Space Center, Cape Canaveral, Florida.

Two early M113 NASA Armored Rescue vehicles. The one nearest the camera has a rectangular shield at the front and is coated with what is believed to be heat resistant asbestos based paste. Photo: ‘Alacrity’ at AR15.com

Mercury-era NASA M113 with Cape Canaveral Fire Department. Photo: Bisney and Pickering

Modifications and Colour

There is some information suggesting that early work with the M113’s involved the use of asbestos added to the exterior either as a paste or as panels bolted on with the intention of protection from the potentially intense heat and flames which might be faced by such as a rescue operation. Photographic evidence of these early vehicles merely shows initially no numbers and at least one vehicle with some kind of coating (see above) and a large rectangular shield at the front. The color of the vehicle is not known and later they can be seen in a dark color but with large numbers painted on the front and sides (and presumably the rear).

NASA M113 Vehicle No.1 during shuttle launch showing the all-white colour but with the ramp open. Photo: NASA
Vehicles 1 and 3 noticeably had a large cab type structure added to the roof over the commander’s hatch at the time. Later photos from the 1970’s show the vehicles painted in a white color with large red numbers. Photos taken in 2014/2015 when the vehicles were being retired showed a more common firefighting luminous-green color with a horizontal reflective stripe and red numbers.

Vehicles No 1 and 2. Photo: NASA


NASA’s M113 based armored rescuer. Illustrated by William ‘Richtor’ Byrd, funded by our Patreon Campaign.

Use

The procedure for using these vehicles at the time of their retirement was that Vehicles 1 and 2 remained on standby at a secure location less than one mile (9/10th of a mile) from the launch site. A third vehicle was kept available, open and uncrewed next to the astronaut’s evacuation bunker. Vehicles 1 and 2 were crewed during launch time with a crew of fully equipped firefighters in silver firefighting suits with self-contained breathing apparatus on.

NASA M113’s Vehicles No.1 and No.3 by the evacuation bunker during launch. Photo: capcomespace.com
Immediately prior to launch, the fully equipped firefighting crew cram into the vehicle while the driver remained outside. He would enter the vehicle at the time of the emergency call. The rear ramp on the M113 would be raised and it would set off on its rescue mission. The reason for this is to do with air supply. Once sealed, the crew of Vehicles 1 and 2 have just 10 minutes to get from their starting point to the launch site, effect a rescue, reenter the vehicle and then get away. 10 minutes is not long at all especially considering the inferno which probably awaits them and the crews train tirelessly to hone their response times because seconds matter. Vehicle 3 sat at the reception point for astronauts by their bunker with the rear ramp open to expedite the astronauts’ evacuation via the slide wire baskets into the bunker. Because Vehicle 3 was a self-evacuation vehicle, all astronauts were trained to operate it.

NASA M113 Vehicle No.2 seen during training as firefighters enter, and a view of the interior of one of the vehicles showing the cramped interior when closed up. Photos: NASA
Photographic evidence shows that over the decades the exact positioning and response for the vehicles had evolved but the essential requirement was the same, evacuating the astronauts in the event of a launch disaster.

Current Status

As of December 2013, the old M113’s were replaced by a more modern alternative, surplus Caiman Mine Resistant Ambush Protected (MRAP) trucks. The M113’s were never used in a real-life rescue. The MRAPs are faster and more spacious than the M113 and just as well protected. The only modification to the Caiman, other than being painted white, is the planned addition of a rear ramp replacing the original steps. However, as of 2015, the Caiman vehicles seen at NASA retained the rear steps and doors. Just like the M113’s, 4 Caimans now fulfill the rescue role for NASA. The status of the M113’s is unknown although Vehicle No.1 can now be seen on a concrete platform outside Kennedy Space Center as a display.

NASA Caiman MRAP (without ramp modification fitted) next to NASA M113s #1 and #2. Photo: NASA

Specifications

Dimensions (L-w-H) 4.86 x 2.68 x 2.50 m (15.11 x 8.97 x 8.2 ft)
Total weight, battle ready 12.3 tonnes (24,600 lbs)
Crew 5 (Commander, Driver, 3 Firefighters/EMT’s)
Propulsion Detroit 6V53T, 6-cyl. diesel 275 hp (205 kW) P/w 22.36 hp/tonne
Transmission Allison TX-100-1 3-speed automatic
Maximum speed 42 mph (68 km/h) road/3.6 mph (5.8 kph) swimming
Suspensions Torsion bars
Range 300 miles/480 km
Armor Aluminum alloy 12–38 mm (0.47–1.50 in)

Links, Resources & Further Reading

www.nasa.gov
M113s Give Armored Ride to Firefighters, Steven Siceloff
Spaceport News, Vol.51. No.6 April 1st 2011
Spaceshots and Snapshots of Projects Mercury and Gemini: A Rare Photographic History, Bisney and Pickering

Categories
Cold War US Vehicle

Amphibious Cargo Carrier M76 Otter

U.S.A. (1950s-1970s)
Amphibious Cargo Carrier – unknown number built

Designed by the Pontiac Motor Division in the early 1950’s as the T46, this vehicle began life as the intended replacement for the Studebaker M29 Weasel. This amphibious cargo carrier was designed to carry cargo or up to eight troops over shallow rivers and swampy terrains and would become the M76 also known as the Otter.
Development started in the late 1940’s with the less than enthusiastic US Army watching on. The Army soon lost interest in the project, but the United States Marines, who have a habit of accepting vehicles which the US Army disapproves of (for example the M103 Heavy Tank), became interested. Production would start on the M76 Otter in the mid-to-late 1950’s.

A factory fresh M76 with the .50 Cal MG ring. Photo: Thomas Laemlein, armorplatepress.com

Design

The Pontiac Motor Division – perhaps better known for their luxury sports cars – built the M76 at their plant in Pontiac, Michigan. It was tested at General Motors military proving grounds in Milford, also in Michigan.
The M76 was almost entirely an aluminum construction. This made the vehicle extremely light, perfect for its intended amphibious role, but also made it vulnerable to enemy fire.

An M76 ‘hell on tracks’ on the move in Vietnam. Note the extensive roof stowage and open roof doors. Photo: SOURCE
Located under a truck-like nose at the front of the vehicle was the engine. This is known as a cab-over-engine layout. This engine was a Continental AIO-268 air cooled, 4-cylinder opposed engine rated at 130 hp. This was originally an aircraft engine. The exhaust, a small pipe bent to rear, was located on just behind the cabin roof. The power from the engine ran to a small, forward mounted drive sprockets; the idler was at the rear. Like the M56 Scorpion, the M76’s road wheels were pneumatic, simply meaning that the rubber around the wheel is inflated, like a standard truck tire. This lightened the vehicle, but also provided extra buoyancy when the Otter was traversing soft ground or water. The wheels were attached to a torsion bar suspension, with 2 wheels per suspension arm (the arm is sandwiched between the two wheels). The sprocket and idler wheels are connected to their closest set of road wheels on an arm.
This is like the compensating idler arm found on American tanks such as the M48, M60, and M103. As the road wheel arm it is attached to moves up and down, it presses either idler or sprocket wheel forward, keeping a constant track tension. The tracks were an evolution of the type found on the Weasel. They were a single long rubber band with added metal cleats and thicker rubber blocks for grip. The tracks were 76.5 cm (30.1 in.) wide. The top land speed of the vehicle was 30 mph (50 km/h). Steering was the traditional clutch type, meaning that one track is slowed allowing the faster track to pivot the vehicle in the desired direction.
Fuel for the M76 was stored in two large fuel tanks mounted externally on either side of the troop/cargo bay. The location of these tanks – and external stowage in general – varied during the Otter’s production. On the early vehicles, such as the T46 prototypes and Mk.1s the tanks were located centrally on the side of the hull. Later Marks, such as the Mk.2, can be identified by the rear mounted fuel tanks.
Behind the engine compartment was a two-man cabin with the driver on the left and a spare seat to his right. The driver operated the vehicle with bicycle like handlebars and is separated from the passenger side by a large round housing for the propeller drive shaft. Above the passenger seat was hatch in the cabin roof, on the outer side of this hatch was a mounting for a Browning M2HB .50 Cal (12.7mm) machine gun. This was the Otter’s only defensive armament. The troop/cargo bay was behind the cabin. It had the capacity to carry either eight fully loaded troops or 3,000 lbs. (1,360 kg) of supplies. The cabin and cargo/troop bay were fully enclosed and insulated. There were traditional truck style doors on the driver and passenger side of the cab. The troop/cargo bay had rear door for loading and unloading. There were also hatches in the roof. Both the driver and crew/cargo bay could be heated via an internal heating unit.

A collective image showing troops loading ‘C’ Rations into the Otter’s cargo bay, a serviceman inspecting the propeller and a surviving M76 with outer roadwheels removed revealing how they are mounted on the suspension arms. First two photos from Thomas Laemlein, armorplatepress.com
Being an amphibious vehicle, the front of the vehicle was built like the bow of a boat. There was a large propeller mounted at the rear of the vehicle under the access doors, below the towing hook. This propelled the Otter when in water, and was folded upwards when on land. Steering in water was conducted by the tracks. This is done by breaking one of the tracks. When turning port or starboard, the stopped track provides resistance as the rotating tracks turn the vehicle. Speed on water was 3.7 – 5.3 knots (7-10 km/h).
As well as carrying troops and supplies, the Otter, much like its Weasel predecessor, could rescue wheeled vehicles from boggy areas where they may get stuck. The Otter was better equipped for this job, however, as all of the vehicles had a 5,000 lb. (2268 kg) capacity winch located in the cargo/troop bay under a fold away seat.

Two M76s traversing a river in Vietnam. The .50 Cal and exhaust is clearly visible on the fore-ground M76. Also, note the centrally mounted fuel tanks on the background Otter, identifying it as an early model. Photo: Thomas Laemlein, armorplatepress.com


M76 Otter by Tank Encyclopedia’s own David Bocquelet.

Service

The Otter was only ever in service with the United States Marine Corps (USMC) who deployed the vehicle in Vietnam with the first 33 vehicles arriving in Danang in 1965. These Otters were assigned to 3rd Motor Transport Bn, 1st Marine Division Fleet Logistics Support Command, 1st Marine Brigade. Usually, three to four M76s were assigned per Infantry Battalion.
The vehicle’s most prominent role was in the 1968 Battle of Dai Do in the Dong Ha sector. A Battle in which Captain Jay R. Vargas was awarded the Medal of Honour. This would later be the recorded in Keith Nolan’s ‘The Magnificent Bastards: the joint Army-Marine Defense of Dong Ha 1968.’
Below is an extract from the book. It is an account of the M76 in action:
“The Otter crews also earned their pay in the resupply effort. Forehand wrote that even though the M76 Otter ‘was always broke,’ the boxy, open-topped, tracked vehicle ‘did more than it was ever designed to do’. The Otter was able to negotiate water obstacles by floating. ‘The vehicle was totally devoid of armor,’ Forehand continued, ‘had a high profile on land, and was mounted with a .50-cal MG that invited RPGs. It was slow and ungainly in water, but could and did perform in places that would not support an LVT. These craft were invaluable and those who manned them were completely without fear.”

An almost fully loaded M76 on a river in Vietnam. The personnel on the rear are sat on the open roof doors. Photo: Thomas Laemlein, armorplatepress.com.
It served throughout the war in its intended role as troop and cargo carrier, but also found uses in light vehicle recovery and as a field ambulance. Some crews would bolt sheet-metal over the Otter’s large cabin windows in an effort to improved protection from small-arms fire. A small slot was cut for the driver to see through. Sheet metal panels were also added around the .50 Cal. mount, giving the appearance of a barrel. This got nicknamed the ‘gun tub’, a name the Marines borrowed from the Navy, as they so often do. This is because the armor around a gun on a ship is called a tub, ie. ‘port side 20mm gun tub’.

Here, the field-applied armor plate over the windshield and plates around the ‘gun tub’ are clearly seen. This is another early vehicle, as evidenced by the central fuel tank. This particular Otter is moving up to support Leathernecks of the 2d Battalion, 4th Marines [2/4] during the fighting around Dai Do Village east of Dong Ha in 1968. Allied forces accounted for over 1,000 confirmed NVA dead in the week-long battle that was part of Operation Napoleon/Saline. Photo: Official USMC photo by Lance Corporal Teacher. From the Jonathan F. Abel Collection (COLL/3611), Marine Corps Archives & Special Collections. www.snafu-Solomon.com.
The USMC would continue to use the M76 into the 1970s in service and supply units, and also for operations in arctic environments. It was replaced in service by the M116 Husky, the next vehicle in the line of Amphibious Cargo Carriers.

Surviving Vehicles

Like its Weasel predecessor, a number of Otters are privately owned and run or displayed at shows like the War and Peace show in Kent, United Kingdom. In 2017, a rare, running example of one of the T46E1 prototypes was displayed. Some privately owned otters have found a use. One vehicle, owned by HQ Transportation, North Pole Alaska, is used to combat wildfires.
They can also be found in Museums, such as the Pacific War Museum on Guam, Isle of Wight Military History Museum in the UK and the Marine Corps Mechanized Museum, Camp Pendleton USA.

The surviving T46E1 at the 2017 War and Peace show in the UK. Photo: Craig Moore

An article by Mark Nash with research assistance from Michael Moore
For our U.K. readers, this article can also be found in the November 2017 issue of Classic Military Vehicle‘ Magazine.


Amphibious Cargo Carrier M76 Otter

Dimensions (L-W-H) 4.90 m x 2.50 m x 2.31 m
(16′ 0.9″ x 8′ 2.5″ x 7′ 6.9″)
Crew 1 driver, 1 co-driver, 8 passengers
Propulsion 130hp Continental AIO-268 air cooled, 4-cylinder
Speed (road) 30 mph (50 km/h)
Speed (water) 3.7 – 5.3 knots (7-10 km/h)
Armament 1x Browning M2HB .50 Cal. (12.7mm) Heavy Machine gun for defense.
For information about abbreviations check the Lexical Index

Links, Resources & Further Reading

Michael Moore, Amateur US Military Historian, US Army, Retired.
Thomas Laemlein of www.armorplatepress.com, who has generously donated the use of images from his personal and commercial collection free of charge.
‘The Magnificent Bastards: the joint Army-Marine defense of Dong Ha 1968’, Keith Nolan
Standard Catalog of US Military Vehicles, 2nd Edition, David Doyle.
Militaryvehiclephotos.com
Steelsoldiers.com
Surviving Vehicles: massimocorner.com
on leatherneck.com