Case Study 3:  M989A1 Heavy Expanded Mobile Ammunition Trailer (HEMAT)

The M989A1 Heavy Expanded Mobile Ammunition Trailer, or HEMAT, (shown at right) is a workhorse trailer that can be configured in several ways.  It is a two axle, four wheeled, wagon-style trailer that weighs nearly five tons, and has a payload of 11 tons.  Primarily designed to carry the Multiple Launch Rocket System, the HEMAT’s versatility, and ease of loading and unloading, make it a valuable logistical asset in support of operations in Iraq and Afghanistan.

Problem:

The approved method of attaching the tow bar to the usual prime mover is documented in TM-9-2330-383-14:

• Remove the davit crane from the Heavy Equipment Mobility Tactical Truck (HEMMT)
• Install it on the trailer
• Hoist the tow bar into position with the crane
• Align and position the vehicles
• Lower the lunette onto the pintle
• Secure the pintle and make connections
• Dismantle the crane
• Reinstall it on the prime mover

An optional alternative method uses the tow strap supplied with the M989A1. Both methods require two soldiers, take many minutes to accomplish, and require the appropriate equipment to complete.
Fast-paced logistics operations demand a better method.  Use of the davit crane takes unacceptably long, and is not even an option if the tow vehicle is not a HEMMT.  The HEMAT tow strap is often missing. As is sometimes the case, units must employ a field expedient method to accomplish their mission.  In connecting a HEMAT trailer, the most common method involves five soldiers using brute force, and risks serious injury – even death.

There are three areas of concern:

1. The tow bar is fixed and cannot move from side to side, making alignment critical.  Misalignment of as little as one-half an inch can cause the risk of injury because soldiers get impatient and think they can muscle the tow bar into place.
2. The differential locking pin must be engaged and disengaged from underneath the trailer.
3. The tow bar weighs 200 pounds, requiring two or three soldiers to lift and hold it in place while the tow vehicle backs toward them, in violation of safety regulations.

Solution:

M989A1 TeleSwivel Lift Assist Kit

The M989A1 TeleSwivel™ Lift Assist Kit (LAK) combines a TeleSwivel™ lunette ring with a self contained winch and a remote differential lock pin lever.  These three features overcome all safety hazards, bringing the process into conformance with US Army safety regulations and guidelines. 

It also provides greater efficiency and speed – a single soldier can now:

• Guide the tow vehicle,
• Quickly attach the tow bar, safety chains, brake line and electric cable, and
• Release or engage (as appropriate) the differential lock pin from a standing position.

The M989A1 Lift Assist Kit clearly improves soldier safety and efficiency.   Here are the key benefits:

• Soldiers are not in the “danger zone” between the tow vehicle and the trailer during alignment.  The TeleSwivel™ process conforms to Army safety guidelines.
• In the best of conditions, the field expedient method takes 3 minutes to connect the vehicles.  The TeleSwivel™ method takes about 30 to 40 seconds. 
• Adverse conditions (rain, snow, sleet, sandstorm, mud or under fire) will certainly extend the time for the process as currently practiced, increasing the risk of injury.  The TeleSwivel™ LAK minimizes these risks.