First Experiments with the Zpacks Duplex Flex Tarp

Tucked quietly away on the zpacks website is the Duplex tarp. That’s the Duplex tent minus the groundsheet and bug netting. Or maybe the duplex tent is the tarp plus the groundsheet and bug netting?

Why I am I being facetious? The way the Duplex tarp is presented, or should I say not presented, one could come to conclude that the tent came before the tarp. Or the tent is so vastly superior to the tarp that the tarp isn’t even worth considering. There’s not even a picture of the Duplex tarp on the zpacks website. There’s just an option to buy the tarp, sight unseen. Please correct me if I’m wrong, but there’s not a single photo of a Duplex tarp on the web, to my knowledge.

With some long walks on my horizon I wanted a shelter that could do it all. I’m already a flat tarp user and while I love having a flat tarp it usually takes me about an hour altogether to get set up perfect. The time it takes from site selection to locking the bug net down can seem like a eternity.

Don’t get me wrong, I enjoy this process. Having a flat tarp means every shelter is customised to your selected site. I enjoy this on walks less than two weeks long but any longer than that and I want a shelter that can be put up quickly and assuredly.

Coming from the perspective of a flat tarp user, I wanted a shelter that could give me the versatility of a flat tarp and the convenience of a freestanding tent. Oh yeah, and it needed to be light. Ultralight. What about bomb proof? What about with massive floorspace? Sound impossible?

So do I take a gamble on the Duplex tent without the groundsheet and bug netting? I’m thinking well, you’re a bit over walking poles. You have been using a zpacks staff for a few years. I love the staff but they’re not the best shelter support unless the peak is the same height as the staff (you have to take the staff apart and then the height is not micro-adjustable).

Also, I said to myself, I want to be able to write while I’m walking. Furthermore, I like picking my nose a lot, and walking poles and nose picking do not go hand in hand.

That was the limit of my thought processes.

I picked the woodland/camo because it’s a bit thicker and a bit darker inside.

Enter the ‘Flex’ freestanding poles. These are some carbon fiber poles that zpacks get from Easton. They weight 280 grams. When the ‘Flex’ freestanding poles were released by zpacks some of the critics over at the Backpackinglight forums chucked in their two cents. Here are some of the objections:

“This flex design seems to me more a case of trying to make the flexible poles fit the design of the Duplex rather than making the most of the poles by having 2 longer continuous poles that cross on each side of the shelter and redesigning the shelter to suit the poles.”

“The idea of using a Duplex without trekking poles sounds cool, except of course the addition of 12oz poles eats a lot of the weight savings that makes the Duplex so great.”

and

“Hmm… agreed… just looking at it, intuitively I don’t see how it can withstand a substantial wind load without collapsing, let alone a good dump of snow. Can that ridge line really support as much tension as one pitched with trekking poles? Looks as if Joe had a pretty good test venue there… Scotland?
But even if it does work, I too cannot see carrying around an extra 11 ounces when I’ve got two perfectly good trekking poles weighing 7.2 oz total.”

The overall consensus was that the ‘Flex’ poles were superfluous ‘if you walk with trekking poles’. A lot of the comments also said that they had never had a situation where  a non-freestanding tent was difficult to pitch easily. Having had some experience with non-freestanding tents, I find this statement hard to believe. I like a drum tight pitch and will spend ages re-positioning stakes and tightening  guylines until it works the way I like. Some people I’ve seen can set their non-freestanding tent up and not care.

For me however I don’t want to carry walking poles and I prefer to have a floor-less shelter. The more I thought about a Duplex tarp combined with the freestanding poles, the more the combination started to make sense. Since I’m limiting my options to not having walking poles, for this comparison I presume you would be carrying the carbon fiber poles with the Duplex tent (not the freestanding poles) that zpacks sells that go into the peaks.

For those of you who don’t have a clue what I’m banging on about, this is the Duplex tent:

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You’ll notice the groundsheet and the netting is sewn to the tarp. You’ll also notice that there are two poles keeping the tent up, one in the middle of each door. These are the dedicated carbon poles zpacks sells. Many hikers use their walking poles to keep the tent up instead of the carbon poles pictured.

I’m comparing the above to this:

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In this photo the netting and the groundsheet are connected but they are separable. There are a variety of groundsheets and nets you can use instead of the ones shown. The netting creates an inner (second) cocoon for the sleeper, this is called a double walled tent. The poles keeping the tent up are on the outside of the canopy and do not require stakes to keep it up.

Some astute readers might point out that the comparison isn’t fair – a non-freestanding single wall Duplex versus a freestanding double walled modular Duplex? Apples and oranges, as the saying goes. Yes, but I’ll give the non-freestanding a head start.

Now, the all important weight numbers.

From the zpacks website, the Duplex full tent numbers are:

– The Duplex Tarp with taped seams and sewn in linelocs weighs 9.5 ounces (269 grams)

– The included guy lines and door clips weigh about 1.2 ounces (34 grams)

– The sewn in Cuben Fiber bathtub floor and bug screen weighs 10.0 ounces (284 grams)

– The included medium-plus 7″ x 13″ stuff sack adds .3 ounces (8 grams)

– The total weight for the packed tent is 21.0 ounces (595 grams).

– If you’re carrying the dedicated carbon poles they’re 60 grams each, so + 120 grams

Total = 715g.

On the other hand, the freestanding Duplex tarp combination comes in at:

– The duplex tarp alone is 9.5 ounces or 269 grams.

– The flex pole set and hardware is 10 oz or 282g.

– Add your own groundsheet (MLD DUO 60g, or zpacks solo bathtub 91g)

– Bug net = Sea to Summit solo nano = 80 grams.

– Guylines = 34 grams

Total = 725g.

Starting to get interesting?

Both weights do not include stakes. Arguably you’ll need less stakes for the freestanding tent than the non-freestanding tent. You could argue you don’t need any stakes, just like Joe does in his set up video.

Zpacks says the non-freestanding tent requires a minimum of 8 stakes, so at 6 grams a piece (for some shepherd hooks and carbon stake combo) = 48 grams, bringing the total to 763 grams.

From my limited experience with the freestanding Duplex tarp (in windy conditions) you’ll need 6 stakes as a minimum; so 12 grams less, bringing the total to 761 grams.

EXACTLY the same weight. A double walled tent at the same weight as a single walled tent? I’m in.

You could use a bivy instead of the groundsheet/net combo as well, saving weight but sacrificing sleeping space.

I saved up and watched the poor AUD/USD exchange rate put the object a few more weeks out of reach and then placed my order and waited eight weeks.

Okay here’s some photos:

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Above: Duplex Flex tarp with shortened x-therm max. Note no bug net.

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The interior space is huge. With all the doors closed there’s 2.2m to roll around in.

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Above: with the DUO Sea to Summit bug net. I’ve since figured out the corners of the bug net are better off being hooked to where the tarp poles meet the ground.

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Above: There are two mid panel tie outs. I’ve read in various places the panels can flap around a lot in high winds. Maybe having two tie outs will help? With the mid-panel toggle connecting the freestanding poles to the tarp there is more head room in the center of the tarp by default.

Not having used a Duplex tent, here are my imagined advantages and disadvantages of the Duplex freestanding tarp over the non-freestanding Duplex tent (integrated floor and bug netting). Some of these comparisons apply to all modular floor-less tarps to integrated tents.

Firstly, price:

When you factor in the price of the carbon poles the Duplex tent is $600 (USD) plus $60. If you had a freestanding full Duplex tent, you’re looking at $750 USD.

The Duplex tarp is $375 USD plus $150 for the Flex poles totaling $525. You then have to factor in the bug net and groundsheet price; S2S bug net ($40USD) and tyvek or polycryo ($10).

Next, set up.

One advantage of the integrated full Duplex tent is that there would be a little bit less stuffing around. Maybe ‘stuffing around’ is the wrong phrase – perhaps, ‘less initial set up time’ is more accurate. I’ve spent a few hours cutting bungee cords and getting the inner net working.

The apparent convenience of the integrated tent comes at the cost of versatility.

As said, for me, I value versatility and ‘modularity’ over maximum convenience. In the context of the freestanding duplex tarp against the non-freestanding duplex tent the convenience is subjective. The floor-less freestanding tarp is more convenient if you’re ‘cowboy camping’ and it starts raining in the middle of the night.  In this video I have a waterproof shelter erected in less than 3 minutes. Keep in mind this is probably the fourth time I have set the tarp up. (The first night I set the tarp up was a day before this in the dark and drizzling rain.)

One of the coolest things for me is that you can plonk the tarp over the top of your sleeping bag, mattress and groundsheet. You can’t do that with an integrated tent.

 

Other advantages of the modular Duplex tarp over the non-freestanding Duplex tent:

I can unhook the inner and use the inner with the freestanding poles and have a freestanding net tent to use in bug infested areas on clear nights or during the day when the flies are out.

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When decamping I can lift the tarp up and move it away from the contents inside. No crouching and crawling in and out of the tent as I pack my backpack. Bonus.

I can then make the walls vertical of the freestanding tarp and let it dry while I finish packing up. Bonus.

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Did I say there are no poles in the doorway?

What if it’s blowing a gale? I can set the tent up with both the inner poles/walking poles and the freestanding poles together. You can grab a stick or two in bad weather to support the ‘Flex’ mode. Bombproof.

Shepherd hooks are actually useful in the corner tie-outs where the poles meet the ground. The tension in the carbon poles pulls the stake loop taught meaning the shepherd hooks won’t rotate and flip out. In fact, in these corners shepherd hooks work better than larger stakes because they are easier to fit in.

You can set it up with the walls vertical or with the walls more horizontal depending on the site size.

Even in a light wind you need at least two stakes to keep the tarp down.

You can carry it around one handed. If I set up on an ants nest, moving is quick.

Finding a flat site is not as critical with a floor-less tarp. The corners of the freestanding tarp can be staked down if one pole hangs in the air. There is no sagging of the bathtub floor if you’re on a uneven site, as discussed at Willis Wall.

With the bug netting set up this is a double walled tent. I already owned a Sea to Summit nano solo and double net-tent from my flat-tarp days. These work well in my opinion. The double wall will collect condensation that gets dislodged when the tarp shakes in wind or by large drops from a tree.

A few companies make inners that would be appropriate for the Duplex tarp. zpacks once made one, but do not offer them for unknown reasons. They do offer a single door hexamid. I was wrong, they don’t.

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Above: the elusive zpacks Duplex inner. Maybe this year zpacks will offer the inners?

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Above: Tarptent make a few that might work?

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Above: Six Moon Designs make a Haven net tent. The ridge line is off centre though, so I’m not sure if it’ll work.

Can you think of any others? Please share. (If you have a good condition second hand one of these inner nets, please message me)

I might try one of these one day but for the moment I’m happy having the bug net and groundsheet separate. If I have the full double walled tarp and bug net set up I can leave the groundsheet and contents where they are on the ground and pull the upper way out of the way. Alternatively I can set up the groundsheet and mattress etc as I need them and add the bug net or tarp later. Usually at lunch or at the end of the day you just want to throw your groundsheet and mattress down and not have to think about how everything is going to work.

Some people like having a seamless groundsheet and bug net, which I can understand. You can get the Sea to Summit bug net and groundsheet pretty tight, especially with oversized tyvek or the polycryo. It won’t be a ‘perfect’ seal though.

Speaking of groundsheets, with this set up they are interchangeable as they wear out.

If there is a downpour in the middle of the day, I do not mind setting the tarp up to sit out the worst of it. When I owned a non-freestanding tent even if I was walking in four foot of water I couldn’t be bothered setting the tent up at lunch-time. Lunch didn’t occur on those days.

This for me defines the beauty of the Duplex ‘Flex’ Tarp – its simplicity. For long hikes I want a shelter I want to use, not a compromise for weight savings. Psychologically I know it’s easy and I know it works. I want to put it up, even when it’s not raining, because it’s so easy.

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Shout out to John Abela for talking through the options with me before making this purchase.

Lastly, here is an example of a summer gear list with the MLD Core pack pictured above.

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