Dominant Logistics
The HEMTT Duck
Anyone who has ever studied logistics cannot help but admire the accomplishments of logistical operations of WWII. It is one thing to engage in amphibious assaults. It is quite another to assault the shores and for all practical purposes rapidly build entire ports and move enormous quantities of men and materials through those ports. During the Normandy invasion, roughly 40% of all men and materials were brought ashore by one vehicle in particular, the DUKW or Duck. All told, only 20,000 of these vehicles were built but they moved over 3,000,000 tons of supplies from ship to shore in a period of less than one year in all of the War's various fronts. This is all the more amazing when one considers that the vehicle was only capable of carrying 2.5 tons of cargo. And this was long before the eras of computers and composite materials.
The Duck was a sort of bastard cross breed of a boat and a truck. It could travel at 55 mph on land or 6 mph in the water. As long as there was something on shore that it could drive on, it could bring supplies to the shore but also move beyond the beach to wherever the supplies needed to go. The drivetrain was based entirely from the 2.5 ton truck, complete with 5-speed transmission and all wheel drive. To be blunt, a strong case can be made for bringing back a modern version of this capability.
Many point to the Gulf War as an example of great logistics but these people are fools. Conditions for moving the Gulf War forces couldn't have been more perfect and yet it still took months to move a force a fraction of the size of forces we moved throughout WWII. We couldn't even begin to engage in the level of logistics that exemplified the support of WWII. The lessons learned have nearly all been lost and we need to do everything we can to regain as much of this knowledge as is possible before we really need it again. Even in the Marine Corps, where amphibious operations are the norm, there is no real capability to move materials from a ship to beyond the shore - we have a wide variety of landing craft, but nothing that can continue onward except for purpose-built combat vehicles like the LAV and Amtrak.
Any long-term military action will ultimately come to rely on ships for transporting supplies to the theater. Even light forces cannot be entirely supplied through the air from CONUS; the distance is simply too great. But we've given up our ability to effectively transfer these supplies from ship to beyond the shore. One of the positives that did come from the Gulf War was the performance of the HEMTT for transporting large quantities of materials. A newer version of the HEMTT is even available with PLS. The obvious answer here is to develop a HEMTT Duck.
The M1120 model of the HEMTT is PLS equipped and can carry 11 tons of palletized cargo in a 20 foot bed. The total dimensions of the Duck would make it only about 12 feet longer than the original with four times the payload capacity. The hull of the Duck will be a boat configuration with access panels underneath for maintenance and the cab would be incorporated into the hull. The HEMTT includes a power-take-off on the transfer case that can be used to power a propeller or waterjet system for propulsion. Bilge pumps will also need to be incorporated to assist in seaworthiness. If we retain our current height, it should be possible for this vehicle to be transported by C-130.
The axles underneath should provide sufficient weight to keep the vehicle stable even in relatively rough waters. It won't be setting any speed records, but it should be able to at least match the original Duck's 6 mph in the water with four times the amount of cargo. On and off road performance should be similar to the existing M1120. This vehicle will be relatively complicated to maintain but it certainly won't be as bad as maintaining a helicopter and this vehicle could carry roughly 50% more cargo than a CH-47.
With this vehicle, we would not only be able to effectively move materials from ship to shore, we would also be able to transport the same materials great distances once on shore. As long at it has something remotely resembling a road, the HEMTT can generally get through. It could also use major waterways as transit routes for more flexibility in delivering supplies. And all it takes to unload the vehicle is working some controls without even leaving the cab.
The HEMTT Duck would dramatically increase our logistics capabilities and it shouldn't require much of an investment. The HEMTT is a proven performer and the Duck version would share most of the same parts. Besides its wartime capabilties, this vehicle would also be a major asset for OOTW. It can carry large quantities of relief supplies to areas that other vehicles could never reach. It would also make an ideal platform for performing rescue work in flood regions by putting a rack of seats on the bed and driving/swimming to wherever people are in trouble.
The HEMTT Duck would make a tremendous addition to the logistics capabilities of the force, taking us one step further to achieving Dominant Logistics.
References
http://members.aol.com/twodukw/twodukw.htm
-----------------------------------------------------
More details on the design of a HEMTT Duck:
Generally speaking, large trucks are designed based on what is above and below the frame. For a HEMTT Duck, we want to design what would essentially be a boat, the bottom of which would incorporate the frame of the HEMTT. This gives us the sealed hull form necessary to float. The suspension and drivetrain would then attached to the underside of the boat. In the space between the mechanicals underneath, I would use non-flammable floation blocks to fill in all the major gaps where there is room. I would also use a non-flammable flexible foam in the tires and get rid of CTIS.
With this approach, the vehicle will not only be amphibious, but it will also be much more resistant to mine and shrapnel damage. Another option is to use the proposed CDMs to give the vehicle a hybrid powertrain and eliminate the mechanical drives altogether. This would give us substantial better off-road capabilities and a more effective hull shape by not having to work around conventional drive axles. It would also eliminate the need of a mechanical drive to pass through the hull making for a stronger and better sealed hull.
-----------------------------------------------------
From An Interested Lurker:
I've been doing some looking at the amphibious HEMMT. I now agree with you
that the principle is possible, but calling it a HEMMT might not be entirely
accurate. It would be better to call it a LARC, built using the HEMMT's
drivetrain components with the end size and weight roughly between the 60's
LARC-5 and LARC-15. Hopefully using a better drivetrain and more wheels will
result in a faster vehicle than the LARCs. The main problem will probably be
(un)loading racks over the stern. *2)
I'm avoiding using the LARC name because it causes so much heartburn in
so many. The LARC was really more of a boat with wheels than anything else.
It's speed limitation was due to not using a suspension, the axles were bolted directly to
the frame - a cheap and absolutely hideous approach.
The HEMTT Duck is intended to be a HEMTT first and a Duck second. The aconym is
Heavy Expanded Mobility Tactical Truck and that is exactly what this design is meant to be
- we're just expanding the mobility even furrther by taking it in the water as well.
It will retain similar on-road and off-road capabilities with the current HEMTT.
Ideally, I would like to see these actually built from existing HEMTTs.
This thing with be a pain in the ass to work on, I cringe when I think about that aspect
of this design (I was a mechanic for 8 years). But if you take this in the context
of the current war in Iraq, I want a vehicle that can grab a load from a ship 10 miles out
in the Gulf, swim to shore, get to the high ground with minimal prep of the beach, hop on
the highways or us dirt backroads and haul that load to the Baghdad area, unload quickly,
swap drivers and return to Kuwait, make a maintenance stop while the crew rests overnight
and do it all over again. I want it operating 16 hours followed by an 8 hour
maintenance and rest stop.
The loading and unloading will be by PLS - we use stern doors that open to the sides and
then just let the PLS do it's thing. Ideally, we'll want the doors to be powered as
well so the whole process is automated for speed and safety. Its a maintenance b****
anyways so might as well go all the way.