SGT Rock's Hiking H.Q.


Hennessy Ultalight A-Sym


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Picture from REI Web catalog.

Weight (advertised): 28oz

Weight (tested): 31oz

Price: $149

Weight limit: 200lb

Contact Hennessy Hammock directly: 1 (888) 539-2930



This Review also posted as part of a test by Backpack Gear Test.

The Story


The Review

Military Training

Storm Set Up

Climbing In


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The Story

If you have never heard about the Hennessy Hammock, start by looking at my original review and hammock tips.

I will begin this review with some background information about my relationship with Hennessy Hammocks. In 2000 I was looking for a lighter shelter than a tent for backpacking. I was looking for maybe some tarp or light tent but hadn't made a choice.  I was stationed at Fort Polk and had been using a net hammock with a poncho as a shelter when in the field and was very pleased with using them except for the bug problems for a place like Fort Polk.


Clark Jungle Hammock - Ultralight

Picture From Clark Jungle Hammocks.

One day while surfing the internet I found a review on The Lightweight Backpacker for a Clark Jungle Hammock Ultralight and seriously considered getting one. I did some research and found the Hennessy Hammock and after some comparisons went with the Hennessy.


My original Hennessy HammockNow this is where it gets interesting. About a month after I got my hammock from REI, the Hennessy Ultralight came out. I was a little pissed because I wanted an ultralight and if I had waited just a month it would have been the one I purchased. So I fired off an e-mail to the company asking if a swap was possible - and I got an e-mail from the owner Tom Hennessy! He offered me a ultralight if I sent in my standard and the difference in price - which I did promptly. We also talked about using Hennessy Hammocks in the field during Army training and about getting an ultralight in camouflage someday. I didn't hear anything else for a year and a half about that.

Me on the AT with my Ultralight - out of the rain!In the meantime I've used my Hennessy Ultralight Hammock for hundreds of nights of Army Training and hiking, in weather from freezing temperatures to temperatures over 100 Fahrenheit, in the sun, in the rain, and even in a hurricane (well it really was only a tropical storm by then) with lots of great nights of sleep. I have converted dozens of hikers to hammock users and have grown to consider it my most favorite piece of gear ever.

Then one day out of the blue I get a short e-mail:

Hi! You're one of the people we've selected to test a new hammock we've designed. What would be the best address to send it to?


Hennessy Ultralight Backpacker A-Sym Hammock

Wow! What brought that on? I accepted without ever finding out what hammock model it was. I had recently heard of the Scout, the A-Sym, and the Safari models. I had no clue which it would be. Low and behold, I get an Ultralight A-Sym in the mail, and guess what. It's CAMOUFLAGE!

I was so stoked I took it to work to show some soldiers. Everyone was very interested, partially because they had seen me in my other hammock for about a year and a half enjoying myself and partially because it was cammo. That part was ultra enticing to them. We set it up and a few of them tried laying in it - wonderfully comfortable.

After that I took it out on a couple of field tests to try various set ups and test it for cold weather comfort.



 The advertised weight is 28 ounces, which is about where my Hennessy Ultralight Hammock comes in at, but the A-Sym comes in at 31 ounces. Why, well we will go into the design and what has pushed the weight up.

Starting with the basic hammock, the net and the bottom are a little larger than the original Ultralight even though they are the same material - no see 'um netting and 70D nylon taffeta 160 x 90 count. According to Tom, they were made larger because the testers mentioned the need for more room in the hammock - must have been big guys. The big difference is the bottom having an asymmetrical shape. Instead of the bottom being diamond shape, the bottom is rectangular. The sides pull out at the right near the knee and the left near your shoulder. The purpose is to make it easier to find a sweet spot to sleep in when laying diagonal to the center line of the hammock. This was always the best way to sleep in all the earlier models of the Hennessy Hammock.

The support rope looks like the rope from the original model Hammock, a nylon cord with some sort of stiff black sleeve. But according to Tom, it is the Spectra Nylon 1450 pound test cord with a nylon cover to prevent fraying which had been a concern to some owners of the Ultralight. They are also about a foot shorter at 8' long each, but to compensate the Tree Hugger Straps have gotten about twice as long at 55". The center support line for the new A-Sym hammock is the same nylon cord as the Original, not the spectra cord used on the Ultralight.

The Fly is now a rectangle, approximately 68"x94". This allows it to cover the hammock's new shape, and actually gives a slightly larger coverage area. It also is built to give you better storm coverage - the technique is to set up the hammock at about 45 angle to the wind, that way the larger area of coverage near your head also blocks out the rain and wind. Another possibility with the new fly exists. Although I am normally against adding weight to an item or making it more complicated, an idea I came up with with the new rectangular fly was to put a poncho hood on it. It is almost the same exact size as an ID Sil Poncho. I recommended this to Tom, and he said his wife Ann had already suggested the same thing. Maybe it will become an option, even if it isn't you could always rig a Sil Poncho as a Fly so your fly could serve double duty.

Because of the increase in size of most parts of the hammock, the package has also gotten bigger. It's about the same size as the Original - about 6"x10", slightly larger than the 4"x10" old Ultralight model.

So, for 3 more ounces and a couple more inches of bulk, you get a larger sleeping area, better cords, better hugger straps, and a larger tarp. Not bad.


The Review

The main thing this hammock was supposed to be was more comfortable, at least that is how it was suggested to me. But after a few times in the hammock I can only say this - it is damn comfortable! More comfortable? I don't think so, but I always thought that the Hennessy Hammock was the best rack I ever got in the field (rack is Army slang for sleep - my wife didn't understand that sentence). But I did find it easier to set up my sleeping system with the A-Sym bottom than in my old Ultralight. Definitely a bonus. I'll discuss that later on under Climbing In.

Another benefit which was suggested was the better storm coverage of the larger A-Sym Tarp. The larger tarps makes a better vestibule (see tips) and the material is large enough to make sure you  set it up with good ventilation in rain storms while still providing the coverage needed. I found the new hammock to work quite well during a rainy, windy Louisiana night during sever thunderstorms and tornado warnings.  More on this is covered under Storm Set Up.

In hot buggy weather the hammock is great. The thin nylon bottom is enough to defeat the worst Louisiana 'skeeters, but thin enough to give you good air flow without feeling all clammy and hot. The netting allows you to sit in comfort while reading, relaxing or sleeping without worry they will get you, and the fly ensures good rain coverage and even better air flow to keep you nice and cool. Because of the great air flow, condensation is a very small concern.

As for sleeping in cooler weather - this is still the hammock's Achilles heel. Because of the thin nylon bottom and the lack of ground under you for insulation, you will have to use some sort of pad/reflector system to make it as warm as a tent on the ground. A good system that works for me is a small insulated pad for under your butt and shoulders - and a car windshield sunscreen as a heat reflector which I'll cover later under Tips.

For areas where there aren't good trees, you can also use a set of trekking poles and 4 stakes to make the hammock into a small bivy tent. I'll also cover this later under Tips.

My conclusion is this: I already loved the Hennessy Ultralight. The new A-Sym is only the logical evolution of the design. For under two pounds you get the most versatile, most comfortable, and the most storm proof shelter I've ever used. Although it is slightly larger and heavier than the old Ultralight - I love it and highly recommend it.


Military Training

Often I have used my original ultralight hammock when doing field training at work for the US Army. Since it is light grey, I would often have to hide it deep in the woods or cover it with my poncho to remain tactical. Tom had told me when I originally e-mailed him that he had sent some of his original model hammocks made in camouflage to JRTC Operations Group to test, but I have only ever seen one being used in the field other than mine.

So when I received the camouflaged hammock, I saw a prime opportunity to do some more field testing! The sad part for me is I'm now a 1SG and spend most of my time with the supply trains for my troop instead of out on the line in the bush like I have been doing for the last couple of years with my other hammocks.

Since I have covered almost every aspect of using a hammock in the other sections of the review, I'll cover the following here:

1. The hammock in non-tactical field situations.

2. Use of the hammock in tactical situations in a secure area.

3. Use of the hammock in tactical situations in a non-secure area.

4. Use of the hammock with other Army gear.

5. Final recommendations.

The Hammock in non-tactical field situations.

A non-tactical situation is one where you have absolutely no enemy expectation so you set up like your car camping  This is normally in situations like a unit gunnery where you go to the range, fire your gunnery exercises, then return to a base camp for rest, refuel, refitting, etc. Often people set up tents or tarps and leave them standing for when they return.

In these situations the Hammock is a great luxury because you can get the optimal pitch site and leave it there over a few days of training. It was at one of these type of training exercises that I spent 5 days in a tropical storm in my hammock.

The Hammock in a tactical situation in a secure area.

A tactical situation in a secure area is where you are facing an enemy but are far enough back or the enemy situation is such that the possibility of enemy contact is low. In these situations you have time to dig in generators, set up and sand bag shelters, use field kitchens to prepare meals etc. Although I'm using the term "secure" you are never really secure 100%, but you have the time to set up a lot of stuff.

In case of an emergency jump, the hammock can be quickly pulled down and stuffed into a ruck to be packed correctly later.

In these situations the hammock still works fine, because in the big scheme of things, it isn't adding a lot to your set up or tear down time. A 2 minute set up or tear down is hardly a liability and with all the other stuff around you, camouflaging your sleeping position isn't a high priority considering the size of your unit footprint. Since the camouflage hammock looks military, it doesn't stick out as some sort of civilian gear brought along where it doesn't belong (at least until the Army adopts it!)

The Hammock in a tactical situation in a  non-secure area.

A tactical situation in a non-secure area is where you are out in the bush against the enemy. In these situations the use of the hammock is iffy. This can include being actually out on OP/LP, in a fighting position, or maybe deep in a hide position. Often times you sleep fully clothed with your field gear on and rifle in your hand.

 Some times you can get deep into a hide and have adequate camouflage, then the hammock works fine, but otherwise it is a liability to being able to rapidly act. In these situations, wrapping up in a poncho, or maybe a poncho and liner is all you can afford to do.

I would have to say that 90% of the time in these situations I would forbid the use of a hammock since it degrades the soldiers ability to fight when needed.

The hammock with other Army gear.

Since I'm operating in a fairly rigid military environment that includes directing what you carry, most of my other gear tends to be official issue on these outings. Sleeping bags, poncho liners, and sleeping pads that include both the Thermarest litefoam long and the good old closed cell foam pad.

Stakes - the orange tent pegs suck for rapid hammock pitching. I ended up making two pegs from a steel rod that could easily be pushed into the ground. On later trips I carried gutter nails.

Sleeping bag - the Army Sleeping bag uses a synthetic fill that is very bulky and doesn't compress well. Fortunately that is a plus in the hammock since it maintains more loft under your body. I used one successfully in the hammock into the mid 30s without a pad.

Poncho liner - when traveling light, and in the hot weather of Louisiana, the poncho liner is great. I combined it with my uniform, a filed jacket liner, and a sleeping pad to stay comfortable even in the high 40s.

Army Thermarest pad - this pad is actually a Thermarest Litefoam long in subdued colors and is now an optional piece of equipment most places and issued in some others. I found the bulk and hassle of the pad to be a negative and prefer my closed cell foam pad for hammocking.

Army closed cell foam pad - similar to the blue closed cell foam pads at Wal-Mart except they are green with built in ties. At 72"x24" and very stiff, they make a great bottom insulation layer to keep you warm in a hammock.

Final Recommendations.

The first thing I should say is the storage bag is a bit of a liability since it has bright white lettering to contrast with the background for easy reading. Although it is a small thing, it could compromise the soldiers security if it was inadvertently exposed. I would recommend that a storage bag be made in OD green with black lettering. It would be harder to read, but it would still be useable. The Army wet weather bag actually has a  set of instructions printed on the side on how to make a watertight seal using the exact same color scheme.

Next I would have to say that if Tom truly wants to get a military contract, the ultralight may be too light. There are many soldiers in my unit over 200 pounds and the Expedition model may be more on the mark for a one size fits all Army. While some soldiers and some small units may be able to make out fine with the Ultralight, the real solution should be a heavier model. But I'm glad I got the ultralight to test - it's perfect for me.

Finally, because I like having multifunctional gear when going to the field, I think a military version that could actually use the Army poncho as the fly instead of making a whole new fly could be a great idea to try. I think to make this work, there would need to be some sort of quick connect system for the tie outs for the corners of the fly to be quickly added or removed from the poncho. To leave them on full time would present a problem when wearing the poncho - imagine strings always hanging off the corners.


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Tom Hennessy