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Reviews > Shelters > Hammocks > Grand Trunk AT Hybrid Hammock > Test Report by Curt Peterson

Grand Trunk AT Hybrid Hammock
Report Series by Curt Peterson

Initial Report - March 2009
Field Report - May 2009
Long Term Report - July 2009


Below you will find:

Initial Report Contents
     Tester Background and Contact Info
     Product Specifications
     Initial Impressions
     Initial Report Summary

Field Report
     Field Report
     Field Report Summary

Long Term Report
     Long Term Report
     Long Term Summary


AT Hammock as Tarp
 
AT Hybrid Hammock (photo courtesy of Grand Trunk)




Initial Report

Tester Background and Contact Information


Name: Curt Peterson
Age: 37
Gender: Male
Height: 6 ft 3 in (1.91 m)
Weight: 270 lb (122 kg)
Email address: nwcurt<at>gmail<dot>com
Location: North Bend, Washington, USA

I live in the Cascade foothills, just 20 mi (32 km) from the Pacific Crest Trail via trails leading right from my backyard. My outdoor time in Washington is spent dayhiking, backpacking, climbing, fishing and skiing everywhere from the Olympic coast to rainforests to Cascade volcanoes to dry steppe. I played football in college and often evaluate products from a big guy perspective. My typical pack load ranges from 11 - 20 lbs (5-9 kg) and usually includes plenty of wet weather gear.

Product Specifications

  • Size:
    • Opened: 10 ft (3 m) long and 6 ft (1.8 m) wide ::: Same as manufacturer lists
    • Packed: 9 in (23 cm) and 6 in (15 cm) and about 5 in (12.5 cm) thick 
  • Weights:
    • Entire unit as shipped: 18.6 oz (531 g) ::: Manufacturer lists as 20 oz (567 gms)
    • Minimum Tarp-only Weight: 16.2 oz (460 g) 

Initial Impressions

As a somewhat-lightweight backpacker, I discovered backcountry hammocking relatively late. I didn't seriously try it out until about two years ago. With so many complex setups and options, it just didn't seem very practical to me. Eventually I found myself with a light parachute nylon hammock and managed to sling it up and crawl in without injuring myself. I was sold after about 3 minutes. Not only was it the most comfortable lounging I've ever experienced in the mountains, but full spine back support seems to have eliminated almost all back discomfort I would normally experience on a trip. Now I find that I NEED to chill out in the hammock for about an hour a day to stay limber and pain-free on a multi-day trip. I call my original hammock "my chiropractor". What started as a luxury item now makes its way into my pack on almost every trip where I'll find two trees.

I am a professional napper and relaxer in the hammock, though I do not sleep particularly well overnight in this setup. I'm a bit of a thrasher and a side-sleeper - both of which can be challenging for me in a hammock. I have always tried to find the lightest hammock that will support me and my 6 year old and then created my own suspension systems. My main concerns have been size and weight capacity. I prefer a wider hammock that can be lounged in sideways for in-camp relaxing and with me and my son the weight is easily over 300 lbs (136 kg) so strength is critical. I did a few overnighters in a hammock and while my back and joints have never felt better, I did not sleep very well. The real test was on a 6+ day trip in the Olympics a couple summers ago. All but one night was in the hammock and I again didn't sleep well. One night we were in an alpine area with no trees and I had to set up my hammock on the ground. It was the best night of sleep on the entire trip. So, my focus began to shift from finding a great camping hammock to finding a light, unobtrusive, versatile hammock that could justify its spot in my pack as a chair or stool replacement so I could retain the benefits of day lounging while not being too burdensome since I'd also be carrying a tent.

I have tried a few different types of hammocks, but my favorites have been the light, strong, parachute nylon variety. They are sold by a few different manufacturers, but the materials are similar and only the colors and dimensions seem to vary. They are inexpensive and very strong and reasonably lightweight. I have found a few shortcomings, however. First, none seem to have the right dimensions. The "single" hammocks are too narrow to sit perpendicular in and still have head support. The "double" hammocks are too wide - great for sitting, but excess fabric makes normal hammocking a bit floppy. My other concern is that the material wets out extremely easy and - though they do dry very quickly - they seem to absorb any moisture that is present.

Enter the Grand Trunk AT Hybrid Hammock. Grand Trunk (transitioning from its old name, The Travel Hammock) has created a hammock with the EXACT length and width I had been looking for. It is a tad shorter than many of the other hammocks, and the width is somewhere between a "single" and a "double" hammock. Based on just the dimensions, I was super interested. But wait, there's more! Turns out Grand Trunk is trying to push this hammock into double-duty as an all-weather (and all-terrain, thus the AT) tarp. My first reaction after viewing the website was skepticism. I just wanted a hammock with the dimensions of the AT Hybrid Hammock and not necessarily anything that would clutter that up. After reading a bit more and thinking about it, however, I believe this idea has a lot of merit. Assuming it works as it should, the AT Hybrid Hammock has the potential to be used on every trip, regardless of the weather. If there are two things we don't have a shortage of in Washington, it's trees and rain. A hammock that could be a lounger in good weather and a kitchen cover or group area in soggy weather sounds pretty intriguing!

The AT Hybrid Hammock arrived with minimal packaging, which I definitely appreciated. It was stowed in its own built-in stuff sack with a couple very small instruction cards. No plastic cases, flashy marketing tags or anything like that. It was even shipped in a recycled USPS Tyvek envelope instead of a cardboard box. Grand Trunk doesn't appear to tout its "green" initiatives on the website, but I appreciated the minimal packaging and marketing. Even the setup instructions are silk-screened onto the attached stuff sack, so they're always handy (see picture). What I did find on the website were a few pictures of the AT Hybrid Hammock in action, along with a short video showing various setups. The main setups they note on the website and in the instructions include use as a ground sheet, overhead tarp, lean-to tarp, A-tent, and of course a hammock.

The material for the hammock is a waterproof coated ripstop polyester. This is quite a departure from the super-breathable silky parachute nylon hammocks, but is obviously necessary to create a waterproof tarp. I'm glad to see polyester used instead of nylon as my experience with tent rainflys has shown polyester to stretch less, have much better inherent waterproofing than nylon, and resist breakdown of the waterproof coating more effectively. There are 2 very long seams that run the length the AT Hybrid Hammock. Both are fully taped for waterproofness. On the perimeter there are 8 webbing tie out points. All are reinforced with sewn patches (see picture). 

Packed AT Hybrid Hammock
AT Hybrid Hammock Stowed for Travel
Tab Detail
Tab Reinforcement Detail

Converting from a tarp to a hammock - or vice-versa - is pretty straightforward. Each end of the tarp has a full-width tunnel. Simply thread the hanging rope through the tunnel, cinch it down, and you have a hammock. I initially thought the threading might be tedious, but it slides through with very little resistance and can be done in just a minute or so. Removing is extremely simple - just a quick pull slides the entire rope/hanging setup out with no problem. I like the dark blue color. It's subtle, looks like it will hide dirt well, and shouldn't be too obnoxious in camp. 

The entire hammock is pretty stiff initially. It's essentially the same material as a tent fly, so it's about as crinkly and bulky as a new tent. This does make it a bit of a tight fit to get into the stuff sack, but it will likely only get easier as time goes on and the material softens. 

My plan is to use a variety of rigging setups with the hammock. I will use the included "free" climbing rope setup, but my experience is that there are better suspension rigs out there that can be purchased or homemade. I have my own webbing setups that will probably be the most common suspension I'll use. For tarping, the AT Hybrid Hammock does not come with any guy lines. I'll most likely use Kelty Triptease or something similar for tarping. I plan on using it as a huge vestibule, rigged on trekking poles as a kitchen cover, and as a simple lean-to for lunch breaks. 

I have few concerns as far as tarp-use goes. As just a tarp, it's plenty beefy with many reinforcements, taped seams, and sturdy fabric. It's certainly more robust than many lightweight tarps I've used without problems. As a hammock, my only initial concerns are about breathability. I'm used to hyper-breathable hammock materials. Most are, in fact, too breathable in my opinion. Even on a relatively warm day I can get quickly chilled in these hammocks without some kind of insulation layer underneath. My concern with this hammock would be that the exact opposite occurs and zero breathability will result in a hot, sweaty hammock. It will likely take until the Long Term testing period to find out if this is an issue since we won't be getting any warm days in the next couple months, but it is an area I will keep an eye on.

I am initially optimistic that the AT Hybrid Hammock will do all things well. For me, my main hope is that the AT will mean not only "All-Terrain", but "All-Trip"! If I can use it as a suspended lounger every time the weather is nice and a large covered area every time it's rainy, it would certainly earn a spot in my pack.

My thanks to Kevin at Grand Trunk and BackpackGearTest.org for the opportunity to test this innovative concept in hammocking!


Initial Report Summary

Initial Likes
  • Almost perfect length and width for my hammocking preferences
  • Simple, light, responsible packaging
  • Construction quality appears flawless
Initial Concerns
  • Curious about how the zero breathability will affect comfort



Field Report


Field Report

I have used the Grand Trunk AT Hybrid Hammock quite a bit over the past two months. It's been on three dayhikes and a backpacking trip. The dayhikes were all in the Cascade foothills in Western Washington. Typical spring days with mild temperatures and overcast skies were the norm. The backpacking trip was a couple days in the Channeled Scablands of Central Washington. Besides trail use, the AT Hybrid Hammock has also been used regularly in the backyard, so durability has been tested as well.

On the Channeled Scablands trip, temperatures were warm and fishing was good, but there were no trees to be found. Literally, there was not a single tree in all of our roaming that weekend. This left hammock use out of the question. It was tarp duty only for this trip. On the dayhikes, it has been used as a lounger, napping hammock, and recliner chair (sitting perpendicular to the hammock suspension). Temperatures were mild and clear skies, making for excellent hanging weather and very comfortable relaxing after hiking, fishing, and exploring.

Tarp Use

The AT Hybrid Hammock works well as a tarp. While it's not catenary cut, it pitches plenty taut and I MUCH prefer the tabs to grommets. My other backpacking tarp uses grommets and I don't care for the stress they put on the lightweight fabric and constantly worry that they will rip out when I need them most. The beefy reinforced tabs on the Hybrid cause me no such worry. I pitched it as a traditional A-frame, with one side pitched higher than the other for easy side entry. Unfortunately my camera batteries died before I set it up, so I don't have pictures of how it worked, although it was very basic. I would obviously use this setup in an emergency situation, but it's not my preferred way to camp. I've never been much of a tarper. I find it is usually too chilly and that I need a warmer sleeping bag to compensate. In addition, waking up with mice on my chest a couple of times in my early days of backpacking has left me pretty happy to either zip shut a shelter or get up off the ground. I've never been too worried about snakes and spiders and creepy crawlies, but I'm not a fan of rodents running across my sleeping bag when I'm in it trying to sleep.

The size is a little tight for my tastes. I know some ultralighters use tarps and ponchos much smaller than
10 ft (3 m) long and 6 ft (1.8 m) wide, but I wouldn't want to be in a driving rainstorm with my long-size sleeping bag and all my gear under a tarp this size. For an overhead tarp during lunch on a hike or a camp kitchen, however, it's great. Quick to deploy if the guylines are already attached and offering plenty of room for a two or three people to sit under, this is my preferred way to utilize the AT as a tarp.

Hammock use

Used as a hammock, I can honestly say that the AT Hybrid Hammock is the most comfortable I've ever used. In part because of the size and in part because of the fabric, the Hybrid is incredibly cozy. I absolutely love the fabric. My favorite hammock fabrics before the Hybrid were the silky parachute nylon type sold by a number of manufacturers. They are very supple and super breathable and softer than most fabrics. The AT Hybrid is almost the complete opposite, yet I find it incredibly comfortable to use. It's much, much stiffer, has essentially no breathability, and is a ripstop polyester with taped seams on one side.  I've found that the stiffer fabric has almost no stretch at all, absorbs no water, isn't noisy despite its "crunchiness", and provides a windproof barrier that makes the hammock much more pleasant to hang in. As most hammockers know, even temperatures in the 60s F (15-20 C) can feel very cold in a hammock as they seem to suck the heat out from below. This isn't a huge deal when camping because a foam pad, insulated air pad, or underquilt is utilized to prevent the loss of heat from below. For a quick nap or trailside relaxation session, setting up an insulation system is a pain. The AT Hammock can be set up so quickly that it is realistic to leave it in the top of a pack and set it up for even a quick 10 or 15 minute break. My back certainly appreciates it, but if doing so causes a chill, it's not worth it. The waterproofing of the AT Hybrid appears to take just enough of the edge off to make this a good option. It's not going to replace insulation by any means, but the gentle breezes that can be really cold on even a warm day in a breathable hammock don't seem to cause the same chill in the Hybrid.

I've been using my own suspension system with AT Hybrid Hammock. It's quick, easy, infinitely adjustable, and very strong. I attach a small sliding buckle to each end of the hammock. From there, it's an easy step to loop my lightweight webbing around a tree and feed it through the buckle (see picture below). No knots. No lines. Takes only a few seconds to hang it and even less to take it down. The climbing rope suspension lines that Grand Trunk included with the AT Hybrid work fine, but the trees I typically encounter in the Pacific Northwest are just way too big for them. In fact, I couldn't find a single tree on my first dayhike that would accommodate the climbing rope. They do stretch a lot on the first couple of uses and the hammock needs to be re-set or it will sag almost to the ground, but once they have had the initial stretch they are good to go from then on. They're definitely not bad for a "freebie" that Grand Trunk includes with its hammocks and it's certainly better than not including anything as is the case with many hammocks. Incidentally, I had the chance to talk to a professional forester about the impacts of hanging from trees. He spends virtually every workday in the woods determining the health of trees and sees what impacts can and do affect tree health. He believes that for the thicker bark trees like the Douglas Fir that are so common out here that even thin diameter rope would have no effect on tree health. While webbing is often preferred by hammockers for tree health, he told me that it would really only matter on thinly barked trees like birch and aspen. To be on the safe side he said to use a young Western Red Cedar (another common Northwest Tree) as a gauge. Anything with bark that is thinner should go with webbing, anything thicker is fine with rope. I found this information pretty interesting as this has been a debate amongst the hammock community for years.

The best aspect of the AT Hybrid Hammock, however, is the size. With so many hammocks on the market now, it seems odd that nobody has made one with this layout, but I find it is absolutely perfect for me. I get a diagonal line much easier. I get no knee strain at all, which can be a common complaint about hammock sleeping. The length is plenty long without the narrowing that can cause shoulder squeeze and the width is luxurious without being floppy like a double hammock can be. It really does find the perfect sweet spot for my use. I have on occasion staked out the hammock (see picture below) and I'm trying to figure out if this actually gives more room or not. So far I can't tell the difference enough to make it worth the extra hassle of setting it up and then being careful to swing so much that I rip them right out. It certainly doesn't seem to affect stability - the AT Hybrid is super stable and I imagine it would take intentional effort to flip out of it.



Buckle Detail
Buckle  and Web Attachment System
Staked Out
AT Hybrid Hammock Staked Out


My only quibble so far with the Hybrid is with packing. The material is as stiff and "crunchy" as it was when it first arrived. That's not a problem when using it - and actually contributes to its comfort - but it makes it a bit bulky to pack. It fits in the attached stuff sack easy enough, although there isn't a lot of room for webbing, guylines, or other accessories. When it is packed, it's fairly substantial. If the silky parachute nylon hammocks can be crammed down to grapefruit size, the AT Hybrid is more like a pineapple-sized package. A big pineapple. It's actually pretty close to the size of a football.

The next two months of testing will really focus on hammock camping. I'll be using it with a full tarp, some sort of bug netting, and various insulation options. I already have a couple trips planned and it will get used daily as we camp our way from Washington to Southern California and back in early July. It will definitely get a workout before testing is complete!

My thanks to Kevin at Grand Trunk and BackpackGearTest.org for the opportunity to test this unique hammock!

Field Report Summary

Field Likes
  • Perfect length and width for my hammocking preferences
  • Waterproof fabric makes hammock more comfortable as far as "chill" and so far has not been sweaty at all
Field Concerns
  • A bit bulky to pack up if space is tight in the pack
Long Term Report

Long Term Report

I've had the opportunity to use the Grand Trunk AT Hybrid Hammock extensively since the Field Report. I used it for a weekend camping in Leavenworth Washington, a night near Medford, Oregon, a couple days just south of San Diego, California, and in the Goat Rocks of Washington. Temperatures have been decidedly warm, with day use between 75 and 90 F (24 to 32 C) and nights ranging from the mid 40s to mid 60s F (7 to 18 C).

I can honestly say it has been a pleasure to test! The AT Hybrid Hammock is simply the most comfortable hammock I've ever slept it. It's not the lightest, the smallest, the biggest, cheapest, costliest, or most fully featured, but it is easily the most comfortable. I credit the dimensions and the fabric for this, and over the past four months this hammock has become my first choice in shelters.

The size is perfect for my needs. As noted earlier, it's got great width without being floppy, has more than adequate length, and the stiff fabric (at least relative to the parachute nylon hammocks) gives it more body than any other hammock I've used. On my recent trip to the Goat Rocks, over two nights and three days my hiking buddy had his name-brand, new hammock just feet away yet was constantly trying to steal time in the AT Hybrid. He actually just called me today to ask if he could borrow it for the weekend even though he owns a spanking new hammock of his own!

It has proven plenty durable. On one of the nights in the Goat Rocks I could hear a scratching sound as I gently rocked in the hammock after climbing in. I ignored it since it didn't seem like a big deal. The next morning I found that a small branch was sticking up and every little swing I made scraped across the end of a broken twig. Upon close inspection, there was no tear, no abrasion, and the waterproof coating (which I have face down while sleeping) seems completely unaltered. I've even begun to break my own rule about anybody hanging in my hammock - NO SHOES! I found myself a number of times lounging with my shoes on and there appears to be absolutely zero wear on the hammock.

The breathability (or lack of it) has proven to be a non-issue. In fact, if anything the extra wind resistance seems to help when I'm swinging without a pad. I have yet to get a sweaty back in even warm temperatures despite the non-breathable fabric, and if there is no wind it's quite comfortable in warm temperatures to hang without any insulation. Still, if there is a stiff breeze the familiar "hammock chill" does happen and therefore I always sleep with insulation. Even in temperatures in the mid 70s F (24 C) last weekend in the Goat Rocks a breezy day left me pretty chilly during an afternoon snooze
without a pad.

One of the things I worried about most - bugs - has proven to be essentially a non-issue. I carried bug netting on two trips but never used it. At night the temperatures cool enough that the mosquitoes and flies aren't a problem and I've slept open-air quite comfortably.


AT Half Fly
AT Hybrid Hammock with OES MacCat Deluxe Tarp Half Closed
AT Hammock Big Guy
AT Hybrid Hammock with a 6'5" (1.96m) big guy happily relaxing


I've been using an Outdoor Equipment Supplier MacCat Deluxe tarp (see picture) and it's a perfect match for the AT Hybrid Hammock. With a full coverage tarp made for hammocks and the AT Hybrid, this has become my go-to shelter setup. My tents are gathering dust right now and that's a first for me as I've never quite been able to make a full commitment to hammocking. The AT Hybrid Hammock has definitely made me a convert for three season backpacking!

Long Term Report Summary

Long Term Likes
  • Size, size, size! Perfect, and the dimensions I will measure all future hammocks against
  • Fabric: Stiff - but not overly so - tough, and super comfortable against the body
Long Term Wish List
  • Perhaps a lighter version - maybe a non-tarp version that wouldn't have the need for the tabs, reinforcements, seam tape, and waterproof coating and would come in a bit under a pound (.5kg)
My thanks to BackpackGearTest.org and Kevin at Grand Trunk for the opportunity to be hammock-converted by the AT Hybrid Hammock!

Read more reviews of Grand Trunk gear
Read more gear reviews by Curt Peterson

Reviews > Shelters > Hammocks > Grand Trunk AT Hybrid Hammock > Test Report by Curt Peterson



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