Hennessy Ultralite Asym Zip Hammock Hex Fly Review
I've spent the last three months testing the Hennessy Ultralite Asym Zip on weekend trips and a week-long section hike along the Appalachian Trail.
The Hennessy Ultralite Asym Zip is an excellent ultralight backpacking hammock weighing approximately 1.1-1.3 pounds with a patented bottom-entry design, asymmetrical shape for diagonal sleeping, and integrated Hex Fly rainfly, making it ideal for weight-conscious backpackers and thru-hikers seeking a complete, lightweight sleep system.
After logging 25 nights in this hammock across various conditions, I'm ready to share my honest assessment. This isn't a sponsored review. I bought this system with my own money after my previous tent failed on a rainy trip in the Smokies.
What you'll find below is a detailed breakdown covering everything from the quirky bottom entry system to real-world weather performance. I'll cover the specs, setup process, comfort level, and whether it's actually worth the investment.
First Impressions
When the package arrived, I was immediately struck by how small the stuff sack was. At roughly the size of a grapefruit, the complete system (hammock, rainfly, suspension) takes up remarkably little space in a pack.
Unpacking revealed the distinctive asymmetrical shape that defines Hennessy's design philosophy. The silnylon fabric feels thin but substantial—a characteristic I've learned is normal for ultralight gear. The integrated ridgeline was already attached, which I appreciated.
My first reaction to the bottom entry zipper was skepticism. It looked awkward. After watching a few YouTube tutorials, I gave it a try in my backyard. It took about 10 attempts before I felt comfortable entering and exiting.
The Hex Fly rainfly surprised me with its coverage area. The hexagonal shape creates more usable vestibule space than I expected from an ultralight fly. I could easily stash my pack and boots underneath.
Build quality appears solid. Stitching is clean and even throughout. The zipper glides smoothly when clean and properly lubricated. The suspension ropes are thin but adequate, though I upgraded to tree straps after my first outing.
Hennessy Hammock - Ultralite Backpacker Zip - A Compact Favourite on The Long Trails
Weight: 1.1-1.3 lbs
Design: Bottom entry asymmetrical
Capacity: 1 person
Includes: Hex Fly rainfly
+ Pros
- Ultralight complete system
- Asymmetrical shape for flat sleeping
- Integrated bug net
- Patented bottom entry
- Compact packed size
- Cons
- Learning curve for entry
- Narrow interior for some
- Zipper maintenance required
- Premium price point
Specifications at a Glance
Here are the key numbers that matter for backpackers counting every ounce:
| Specification | Measurement |
|---|---|
| Total Weight | 1.1-1.3 lbs (500-590g) |
| Hammock Body | ~18 oz (510g) |
| Hex Fly | ~8 oz (227g) |
| Suspension System | ~3 oz (85g) |
| Packed Size | 6 x 4 inches |
| Weight Capacity | 200 lbs (90 kg) |
| Length | 10 feet (3 meters) |
| Fabric | 40D ripstop silnylon |
| Bug Net | Integrated no-see-um mesh |
| Ridgeline | Integrated, non-adjustable |
The weight breakdown above shows where the grams go. For context, a typical ultralight tent weighs 2-3 pounds. The Hennessy system saves roughly a pound compared to most solo tents.
Design and Key Features
The Hennessy Ultralite Asym isn't just a scaled-down version of larger models. Every design choice serves weight reduction while maintaining functionality.
Asymmetrical Shape
Asymmetrical Design: A hammock shape intentionally offset from center, allowing you to lie diagonally across the fabric for a flatter sleeping position with better back support.
The asymmetrical cut is the secret sauce here. Instead of hanging straight like a banana, you sleep diagonally across the fabric. This positioning keeps your head and feet elevated while your body remains nearly flat.
I tested this extensively. When I lie straight, my back curves uncomfortably. When I shift to a diagonal position, my spine aligns naturally. The difference is significant for multi-day trips.
Bottom Entry System
This is the most polarizing feature of any Hennessy hammock. You don't climb in from the side or top—you enter from underneath through a velcro-sealed slit and zip it closed behind you.
The system sounds strange but works well once learned. The velco seals automatically when you lie down, creating a bug-proof barrier. The zipper runs along one side, allowing easy entry and exit.
I found it takes about 3-5 nights to become second nature. The biggest advantage is that you can't accidentally leave the door open for bugs. The biggest downside is the learning curve for new users.
Integrated Ridgeline
Ridgeline: A cord running from head to foot that maintains the hammock's shape and hang angle regardless of tree spacing, ensuring consistent comfort.
The permanent ridgeline sets this hammock apart from budget options. It maintains the proper curve regardless of how far apart your trees are spaced. This means consistent comfort every night.
The ridgeline also serves as a handy attachment point for a gear loft or headlamp. I use it to hang my light within easy reach.
Hex Fly Rainfly
The included Hex Fly provides adequate coverage for most conditions. Its hexagonal shape creates a streamlined profile that sheds wind effectively while offering decent vestibule space.
I've experienced rain in this system on four different trips. Light to moderate rain isn't an issue. Wind-driven rain from certain directions can result in some spray entering the hammock area.
Integrated Bug Net
The no-see-um mesh netting attaches to the ridgeline and drapes over the sleeping area. It's permanently attached, which saves weight but means you can't remove it for bug-free winter camping.
When not in use, the net stuffs into a pocket on the ridgeline. This feature works reasonably well, though stuffing it can be slightly awkward with one hand.
Setup Process
Setting up the Hennessy Ultralite Asym follows a consistent process. After 25 nights, I can complete the entire setup in under five minutes.
- Find Suitable Trees: Look for two healthy trees 12-15 feet apart with at least 6-inch diameter trunks.
- Attach Suspension: Wrap the tree straps around each trunk at approximately head height (roughly 5-6 feet off the ground).
- Hang Hammock: Clip the hammock suspension lines to the tree straps using the provided carabiners or figure-9 tensioners.
- Adjust Height: The hammock body should hang with the bottom about 18 inches off the ground. This ensures safe entry and exit.
- Install Rainfly: Drape the Hex Fly over the ridgeline and stake out the corners using the guylines provided.
- Final Adjustments: Check that the hang angle is roughly 30 degrees from horizontal. Test the hammock before committing for the night.
⏰ Time Saver: Pre-attach your suspension lines to tree straps at home. This saves 2-3 minutes per setup in the field.
The learning curve focuses mostly on achieving proper hang height and angle. Too high and entry becomes difficult. Too flat and you'll feel like you're sleeping in a banana.
Comfort and Sleep Quality
Comfort is subjective, but I can share my experience across different scenarios. Your mileage may vary based on body type and sleep preferences.
Sleep Position
The asymmetrical design encourages diagonal sleeping. When I position myself correctly—head left, feet right—I achieve a nearly flat back position. My spine remains neutral throughout the night.
Side sleeping is more challenging. The Ultralite model sacrifices width for weight savings. At its narrowest points, the fabric hugs my shoulders. I can side sleep for short periods but usually wake up and shift to my back.
Stomach sleeping isn't really an option in any hammock, and this one is no exception. The fabric contours too closely to your body for prone positioning to work comfortably.
Sleeping Pad Compatibility
Cold air circulation beneath hammocks makes insulation mandatory. The Hennessy works well with inflatable pads designed for hammock use.
I use a 3/4-length inflatable pad that slides between the double bottom layers. This arrangement keeps the pad positioned underneath me throughout the night without shifting or sliding off.
Wide pads present challenges. The narrow hammock body doesn't accommodate extra-wide models comfortably. Standard-width pads (20-25 inches) work best.
Temperature Range
With proper insulation, this hammock works well into shoulder seasons. I've slept comfortably in temperatures down to 40F using a 20-degree underquilt and a summer-weight sleeping bag on top.
Below freezing requires serious insulation investment. The open-bottom design means cold air can sneak through any gap in your under-quilt or pad system.
Side Sleeper Analysis
Forum research confirmed my experience: side sleepers often find the Ultralite model too narrow. If you primarily sleep on your side, consider the wider Explorer or Expedition models instead.
That said, occasional side sleeping is manageable. I sometimes shift to my side for 30-60 minutes before returning to my back. It's not ideal, but it's doable.
Weather Protection with Hex Fly
The included Hex Fly provides adequate protection for most three-season conditions. I've tested it in rain ranging from light drizzle to moderate thunderstorms.
Rain Performance
During steady vertical rain, the Hex Fly performs well. Water sheds efficiently from the silnylon surface, and the hexagonal shape directs runoff away from the hammock.
Wind-driven rain presents more challenges. Strong winds from certain angles can drive spray under the fly edges. I've experienced minor dampness on two occasions during stormy weather with gusting winds.
Vestibule Space
The hexagonal shape creates two usable vestibules on either side of the entry point. I can easily fit my 65-liter pack and boots underneath with room to spare.
This covered storage area is a significant advantage over minimalist tarps. Having accessible gear storage without exposure to rain or dew improves the overall camping experience.
Bug Protection
The integrated no-see-um mesh provides excellent insect protection. I've camped in mosquito-heavy areas during peak season without a single bite inside the net.
The velcro seal along the bottom edge creates a secure barrier. As long as you enter and exit properly, bugs can't find their way inside.
Durability and Build Quality
After three months of regular use, the hammock shows minimal wear. The silnylon fabric has proven more durable than its thin appearance suggests.
Fabric Quality
The 40D ripstop silnylon feels delicate but resists tears effectively. I've brushed against tree bark, pine needles, and rocky surfaces without damage.
Forum research indicates these fabrics can last 5+ years with proper care. Thru-hikers routinely report 1,000+ trail miles without catastrophic failure.
Zipper Reliability
The bottom-entry zipper represents the most common failure point. My research uncovered several zipper failure stories, typically after 12-18 months of regular use.
Maintenance makes a significant difference. Clean the zipper regularly with a soft brush and lubricate it with a silicone-based product every 10-15 nights of use.
✅ Pro Tip: Always zip the entry fully closed before storing. This prevents the zipper from developing kinks or bends that lead to failures.
Stitching and Seams
Stitch quality appears excellent throughout. All stress points are reinforced with bar-tacking or multiple rows of stitching. After inspecting the entire system, I found no loose threads or weak points.
Warranty and Support
Hennessy Hammock offers a warranty against manufacturing defects. Forum users report positive experiences with warranty claims, though some note that shipping costs are typically the customer's responsibility.
Alternative Hammocks to Consider
The Hennessy isn't the only game in town. Depending on your priorities, several alternatives might serve you better.
| Hammock | Weight | Entry | Best For |
|---|---|---|---|
| Hennessy Ultralite Asym | 1.1-1.3 lbs | Bottom | Weight-conscious backpackers |
| Warbonnet Blackbird | 1.5-1.8 lbs | Side | Side sleepers |
| Dream Hammock | 1.0-1.4 lbs | Various | Customization enthusiasts |
| ENO SingleNest | 1.1 lbs | Top | Budget buyers (no fly included) |
Who Should Consider Alternatives?
Side sleepers might prefer the Warbonnet Blackbird, which offers more interior width while remaining reasonably lightweight.
Budget buyers should consider that the Hennessy system is a premium product. While complete systems cost more upfront, they include everything needed for hammock camping.
Beginners might find simpler top-entry hammocks easier to learn. The Hennessy bottom entry requires practice and patience.
Who Benefits Most from the Hennessy?
Ultralight backpackers will appreciate the complete system weight. At just over a pound for everything, it's hard to beat.
Thru-hikers benefit from the proven reliability. The design has been tested on long trails for decades, and replacement parts are readily available.
Bug-conscious campers will value the integrated netting and sealed bottom entry. Total bug protection requires no extra effort or gear.
Frequently Asked Questions
How much does the Hennessy Ultralite Asym Zip weigh?
The complete system including hammock body, Hex Fly rainfly, and suspension weighs approximately 1.1 to 1.3 pounds (500-590 grams) depending on configuration. The hammock body alone is about 18 ounces, while the Hex Fly adds roughly 8 ounces.
What is the weight capacity of the Hennessy Ultralite Asym?
The Hennessy Ultralite Asym has a rated weight capacity of 200 pounds (90 kilograms). This is lower than heavier Hennessy models like the Explorer or Expedition, which accommodate higher weights. Exceeding this capacity may stress the fabric and compromise safety.
How do you set up a Hennessy bottom entry hammock?
Find two trees 12-15 feet apart with 6-inch diameter trunks. Wrap tree straps around each at head height (5-6 feet up). Attach the hammock suspension lines to the straps. Adjust hang height so the hammock bottom is 18 inches off ground at a 30-degree angle. Drape the Hex Fly over the ridgeline and stake out the corners.
Is the Hennessy Ultralite Asym comfortable?
The asymmetrical design allows for comfortable diagonal sleeping that keeps your spine relatively flat. Back sleepers typically find it very comfortable. Side sleepers may find the narrow width constraining. Comfort improves with proper technique and a few nights of practice finding your ideal position.
Does the Hex Fly provide good rain coverage?
The Hex Fly provides adequate rain protection for typical three-season conditions. It handles vertical rain well and offers decent vestibule space for gear storage. However, strong wind-driven rain from certain angles can result in some spray entering the hammock area. For severe storms, additional coverage may be beneficial.
Can you use a sleeping pad in a Hennessy hammock?
Yes, sleeping pads work well in Hennessy hammocks. The double-bottom design allows you to slide a pad between the fabric layers, where it stays positioned throughout the night. Standard-width pads (20-25 inches) work best. Extra-wide pads may be too large for the narrow Ultralite model.
What is the difference between Hennessy models?
The main differences are weight capacity and packed size. The Ultralite is the lightest at 1.1-1.3 lbs with a 200 lb capacity. The Explorer series offers more room and higher capacity but weighs more. The Expedition models provide maximum space and weight capacity but sacrifice packability. All share the same asymmetrical design and bottom entry system.
Is Hennessy Hammock worth the money?
For weight-conscious backpackers and thru-hikers, yes. You receive a complete, tested system that has proven reliable over thousands of trail miles. The integrated bug net, rainfly, and suspension work together seamlessly. While premium-priced compared to basic hammocks, the total package delivers excellent value for serious users who prioritize weight savings and proven design.
Final Verdict
After 25 nights across varied conditions, I've developed a clear opinion of the Hennessy Ultralite Asym Zip.
This hammock delivers on its core promise: a complete, ultralight sleep system that handles three-season conditions effectively. The asymmetrical design actually works for comfortable diagonal sleeping once you find your position.
The bottom entry system initially frustrated me, but now I appreciate its genius. It can't accidentally be left open, it seals itself when you lie down, and it becomes second nature with practice.
The Hex Fly provides adequate coverage for most backpacking scenarios. Serious storms in exposed locations might leave you wanting more coverage, but for typical three-season conditions, it gets the job done.
Is it worth the investment? For weight-conscious backpackers and thru-hikers, the answer is yes. The system weight is hard to beat, and everything works together seamlessly.
Buy it if: You prioritize weight savings, you're willing to learn a new entry system, you primarily sleep on your back, and you want a complete hammock system from day one.
Skip it if: You primarily sleep on your side, you want maximum storm protection, you're on a tight budget, or you prefer simpler gear without learning curves.
The Hennessy Ultralite Asym Zip earns a solid recommendation for its target audience. It's not the perfect hammock for everyone, but for ultralight backpackers who understand its strengths and limitations, it's an excellent choice.