The Cowboy D.A.R.T. (Dyneema Asym Recon Tarp) * 90 GRAMS!
This is a design and a project that I mulled over for more than a year, being a big proponent of the virtues asym tarps for hammock camping.
If you want to see what a 90-gram tarp that covers an 11-foot gathered-end hammock looks like, read on...
My thanks to Dutch and Alex at Dutchware Gear for their input and contributions in helping me bring this idea to fruition.
Here was my result...
Type: Compact directional parallelogram asym hammock tarp
Materials: 0.51 oz Dyneema composite fabric, 1/2" poly grosgrain ribbon, 1/2" Beastee Dee rings, McNett Seam Grip, 1/2 DCF bonding tape. Mara 70 thread
Ridge Line Length: 128"
Weight: 3.2 oz (90 grams!)
The Cowboy D.A.R.T. (Dyneema Asym Recon Tarp) is an ultra-lightweight weather protection option for the hardcore hammocker.
D -- Its construction is approximately 92% Dyneema composite fabric (by weight) using mostly no-sew methods
A -- It's a very precise, highly abbreviated parallelogram shape designed to be hung with asymmetrical directional pitch
R -- It's best suited for recon hikes where you want to move fast and light to survey a large wilderness area quickly
T -- It's a tarp!
Dyneema composite fabric (AKA DCF AKA "The Fabric Formerly Known As Cube Fiber") is intriguing to many of us. It doesn't just sing a siren song of lighter weight; it puts on an ultralight Super Bowl half time show with a two-story speaker stack, pyrotechnics, and a Jumbotron in the background. It boasts unrivaled light weight in a variety of thicknesses from sensible to stupid. It flirts with danger with minimal abrasion and puncture resistance despite its unparalleled tensile strength in comparison to conventional outdoor fabrics. It has boatloads of high-tech appeal for gear nerds with its ultra-high molecular weight polyethylene (UHMWPE) weave and its signature translucency. In terms of aesthetic appeal it is unabashedly homely, fairly coarse, and acoustically irksome, and yet somehow -- like a last-minute prom-date -- it fills one with hope that it will perform beyond expectation when put to the test -- making DCF downright sexy despite its trade-offs.
One issue for designing tarps with DCF compared to conventional fabrics is that it is narrow in width at around 54" compared to standard-width waterproof fabrics that are 58" to 64" off the roll.
Because the DCF is kind of precious and because the shape of such a minimalist tarp is absolutely critical if it is going to provide effective weather protection, I cobbled together two asym tarp mock-ups out of cheap fabric using my proposed dimensions for the final Cuben Fiber version, just to make sure I got this right the first time when using the DCF. Here is the second conventional fabric mock-up, pitched in a (mostly) "storm mode"...
Measured out the usable width of my sample, and it actually came in at a scant 55" after the selvage edge is removed, almost an inch wider than claimed. I don't know if this is typical or if there is a touch of variance from roll to roll on the DCF material, but because the width of the usable fabric is so critical, I went ahead and tweaked my asym tarp dimensions to allow for Cuben Fiber that is 54" to 55" wide in usable width, just in case fabric runs used for tarp construction vary slightly.
As you can see over an 11-foot hammock with a 110" ridge line, this is one SMALL tarp -- and yet with a proper pitch it does the job!
I consider Jared's Simply Light Designs Simplicity Asym tarp to be kind of the gold standard for a standard-width parallelogram asym tarp; it works, and I have used one extensively over the last couple of years in a lot of really bad weather, so I have learned a lot of the tips and tricks necessary to stay dry under one.
The SLD Simplicity uses a 140" ridge line, 15" overhangs, and a 73-degree angle over the gathered ends. It has an effective (hex-equivalent) width over the head and feet of almost 90" and puts the side tie-outs about 30" away from the hammock midpoint in either direction. Total coverage area is 6300 sq in.
My final D.A.R.T. design uses a 128" ridge line, 9" overhangs, and a 77-degree angle (4 degrees wider) over the gathered ends. It has an effective (hex-equivalent) width over the head and feet of about 88" and puts the side tie-outs about 29" away from the hammock midpoint in either direction. Total coverage area is 5830 sq in (about 8% less).
The D.A.R.T. is shorter at the ridge line out of necessity, better matched to the length of the hammock ridge line, allowing the narrow DCF composite to rotate a couple of degrees for maximum effective width while still covering the head and footbox adequately.
The main trade-off -- other than coverage area -- is the shorter overhang distance at the ends, requiring more precise centering to make sure that the vulnerable long edges on the sides opposite the head and feet get adequate coverage. That makes this tarp a bit intimidating for novice users and much more geared toward hardcore ultralighters and serious gram weenies. It is amazing how much difference a couple of inches on each side makes, as this tarp feels significantly smaller than my SLD asym and definitely skimpy compared to my K.I.S.S. 6' x 9' rectangular asym made from Dutch's Xenon Wide waterproof fabric, which has the same ridge line length on the diagonal but boasts a 13-degree wider corner over the gathered end.
Trailworthiness was not sacrificed, even though 0.51 oz Dyneema fabric was chosen for the tarp panel. The corners are a quadruple-layer bonded design, and the whole tarp is "no-sew" -- bonded reinforcements with taped single-fold hems -- save for a box-X stitch pattern at each tie-out through two internal layers of DCF, with the grosgrain ribbon tie-out bonded and sandwiched between the main panel and an additional underside patch. There are no holes in the tarp panel, and every corner is four layers thick. Transitions between thicknesses are offset to smooth out the transitions so that the tarp can be flipped in the opposite lay direction without catching rain or creating unsightly visual aesthetics.
On the bright side, the D.A.R.T. redefines LIGHT WEIGHT for hammock tarps. My K.I.S.S. 6'x9' typically weighs in at around 8.5 ounces.; the DCF D.A.R.T. tips the scales at a little over 3 ounces -- 90 grams -- which is less than half the weight. That's a savings of well over a quarter pound of what is already one of the lighter tarp solutions available, 60% to 80% lighter than most two-panel conventional tarps and still a couple of ounces lighter than the skimpiest CF hex (with half as many stakes and guy lines too). It is also cost-effective compared to a DIY Cuben two-panel hex or rectangle in terms of its use of this expensive material for someone looking to build their own tarp, since it takes only 3.5 yards of Dyneema fabric.
The D.A.R.T. is a dialed-in single-panel Dyneema asym tarp. In my research I noticed that Zpacks seems to use two-panel construction on their 132" DCF asym tarp, which is basically just a CF hex with two of the corners deleted, but the shape is ineffective because they didn't really sweat the dimensions or consider the effects of ridge line length on proper pitch over an 11-foot hammock with a 110" ridge line. Hammock Gear does a significantly better job of shaping their two-panel DCF asym tap IMHO, but for DIY its hard to beat the economy and weight savings of a single-panel design cut to just the right shape.
I think the D.A.R.T. comes pretty close. Field tests this spring and summer will have the final say.
As with most DCF tarps, the D.A.R.T.'s packed size is not its top selling point; it packs down smaller than almost any hex tarp, but it is bulky compared to most rectangular or parallelogram asym tarps, including those with substantially more coverage area.
In terms of pitch performance, centering is critical with the D.A.R.T., and one is advised to pull out all the tricks of the trade that savvy asym tarp hangers like to use -- like running the hammock suspension under the short edges of the tarp rather than through the "V" at the ridge line tie-outs to tweak the positioning of the tarp and protect the hammock under the vulnerable long edges. Resisting the urge to pitch the sides down steeply is another tip, opting instead to find the "sweet spot" offered by a more moderate wingspan even in a downpour. Minimum pitch height over the hammock ridge line is less than 4", recommended during inclemencies. A taut pitch is effortless with the D.A.R.T., and there is no need to crank out the ridge line or lateral tie-outs under high tension to avoid flapping, since its parallelogram shape slips the wind relatively easily. Best of all, your 90-gram tarp only requires two guy lines and two stakes (which your hammock tie-outs can share, if you use them), cutting your tarp accessory weight by at least half.
Less is more, but sometimes less can be...less. Two caveats related to the shape of this asym tarp and its practical use...
1) If you've much taller than 6'2" (my height) you may find this tarp is too small in bad weather, depending upon the angle of your diagonal lay, because your head and/or feet may project too far for adequate protection.
2) If you have a very wide hammock body (64" or more) you may find that the deeper pocket that the extra fabric width affords you makes this tarrp too small in bad weather, again depending upon the angle of your diagonal lay, because your head and/or feet may project too far for adequate protection.
This was my first-ever experience working with Dyneema composite fabrics and related construction materials (1/2" double-sided bonding tape and Seam Grip adhesive), and I was able to achieve quite satisfactory results, although the process seemed intimidating until I got under way.
Knowing what I know now about what works during the build process, I'll begin drafting a complete step-by-step DIY tutorial article that should be available at Dutchware Gear in the Articles section by the end of the month. You can order everything you need to build your own D.A.R.T. from DWG.
Thanks for reading this project report.
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Originally Posted by cmoulder
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