Tarp specs explained: waterproof ratings, taped seams, denier and ripstop
A tarp's waterproof rating in millimetres describes how much water pressure the coated fabric is rated to hold back, expressed as the height of a column of water: 5,000 mm is fully waterproof in rain, and 20,000 mm is extra margin against pooled water, wet snow and years of wear. Denier (the D in 40D or 70D) is the weight of the yarn, so 70D is heavier yarn than 40D; ripstop is a weave with heavier threads in a grid so a tear stops at the grid. Taped seams cover the needle holes along every seam so the stitching does not leak. The AquaQuest Defender is 70D nylon with a heavy TPU coating rated to 20,000 mm with heat-taped seams; the Safari (70D ripstop nylon), Guide (40D ripstop nylon) and Survivor (70D ripstop nylon) are rated to 5,000 mm with every seam taped; the Pharaoh bivy is 70D nylon with a ripstop upper, rated to 10,000 mm.
The waterproof rating
The rating is a hydrostatic head figure: the height of a water column, in millimetres, that the fabric is rated to resist before water passes through. Falling rain, even heavy rain, puts very little pressure on fabric. The pressure comes from water pooling in a sag, from wet snow sitting on the roof, from a pack or a shoulder pressed against a wet wall, and from the slow wear of a coating over years of use. So the number is less about whether rain gets through and more about how much pressure and abuse the coating has in reserve.
That is why 5,000 mm and 20,000 mm are both honest ratings for a camping tarp. The Safari, Guide and Survivor are rated to 5,000 mm; owners sleep under them through multi-day rain. The Defender is rated to 20,000 mm, four times that figure, and it is the tarp for a basecamp that stays up for days, where the roof may carry pooled water or wet snow at some point. The Pharaoh bivy sits between them at 10,000 mm, with a breathability rating of 10,000 grams per square metre per day, because a bivy has to let your breath out as well as keep rain off.
Two things the rating does not tell you: whether the seams leak, and how the tarp is pitched. A steep, tight pitch sheds water before it can pool; a sagging one makes a puddle that tests the coating every night.
Coatings
The coating is what makes nylon waterproof; uncoated nylon is not. The Defender carries a heavy TPU (thermoplastic polyurethane) coating with a DWR finish. The Safari, Guide and Survivor carry silicone and PU (polyurethane) coatings. The Pharaoh carries PU and DWR. DWR is a durable water repellent finish on the outer face: it makes water bead and run off, which keeps the fabric from wetting out and getting heavy, and it wears with use and sun. The waterproofing underneath it is the coating itself.
Both the Defender and the Safari are 70D nylon. The difference in weight between them, 2.4 lb against 1.3 lb for a 10 x 7, is the coating.
Taped seams
A panel of coated nylon is waterproof. The moment two panels are stitched together, the needle punches a line of holes through the coating, and under rain those holes wick water through to the inside. On an untaped tarp you find out on the first wet night, with a line of drips exactly along the seam. The fix is either to seal every seam yourself with a tube of sealant, and redo it as it wears, or to buy a tarp whose seams were taped at the factory.
Every seam on every AquaQuest tarp is taped. The Defender's are heat-taped. There is nothing to seal yourself on any of the four tarps. The Pharaoh's product page does not state its seam construction, so this page makes no claim about it.
Denier: what 40D and 70D mean
Denier measures the weight of a fixed length of yarn, so it tells you how heavy the threads are. Higher denier means heavier yarn, which usually means a heavier fabric that stands up to more abrasion. Lower denier means lighter yarn and a lighter tarp. It is a measure of the yarn, not of the finished fabric, and on its own it says nothing about waterproofness; that comes from the coating.
In the AquaQuest range the Guide is 40D, the lightest yarn, and the Safari, Defender, Survivor and Pharaoh are 70D. That is why a Guide 10 x 10 weighs 1.3 lb and a Safari 10 x 10 weighs 1.7 lb with the same coatings and the same 5,000 mm rating.
Ripstop
In a ripstop weave a heavier thread is woven in at intervals in both directions, which shows as a faint grid in the fabric. If something punctures the fabric, the tear runs until it reaches one of those heavier threads and stops. That is what lets a light 40D fabric take a snag that would run across a plain fabric of the same weight.
The Safari, Guide and Survivor are ripstop nylon. The Pharaoh has a ripstop upper. The Defender is not ripstop: it is 70D nylon carrying the heaviest coating in the range, and its product page puts the trade-off plainly as "Not Ultralight. Ultra Reliable."
Tie-outs and ridgelines
The fabric rarely fails first. Wind loads the attachment points, so what they are made of matters as much as how many there are. AquaQuest tie-outs are reinforced webbing loops, 3/4 inch wide: polypro webbing on the Defender, grosgrain webbing on the Safari and Guide, and grosgrain with reflective on the Survivor. The ridgelines are webbing-reinforced. A Guide owner on aquaquest.com: "... it folds down very small, and I really like the integrated webbing for easy staking ..." (DD_Hokies)
Counts by model: Defender 19 to 47 depending on size, Safari 15 to 29 with 3 along the center ridgeline, Guide 13 to 23 with a center loop for overhead hanging, Survivor 19 or 29 with reflective webbing. The count for every size is on the size page.
Warranty and care
Every AquaQuest tarp and the Pharaoh bivy carry the Lifetime Warranty to the original owner against defects in materials and workmanship. Any coating wears over time. Dry the tarp before you store it, keep it out of long sun exposure when it is not in use, and take it down between trips; these are camping tarps, made to be pitched and packed, not left standing for a season.
Spec table
| Product | Yarn | Weave | Coating | Waterproof rating | Seams | Tie-outs |
|---|---|---|---|---|---|---|
| Defender tarp | 70D nylon | Not ripstop | TPU and DWR | 20,000 mm | Heat-taped | 3/4 inch polypro webbing, 19 to 47 by size |
| Safari tarp | 70D nylon | Ripstop | Silicone and PU | 5,000 mm | Taped | 3/4 inch grosgrain webbing, 15 to 29 by size |
| Guide tarp | 40D nylon | Ripstop | Silicone and PU | 5,000 mm | Taped | 3/4 inch grosgrain webbing, 13 to 23 by size |
| Survivor tarp | 70D nylon | Ripstop | Silicone and PU | 5,000 mm | Taped | 3/4 inch grosgrain webbing with reflective, 19 or 29 |
| Pharaoh bivy | 70D nylon | Ripstop upper | PU and DWR | 10,000 mm (10,000 g/m2/day breathability) | Not stated on the product page | Dual YKK zippers (no tie-outs) |
FAQs
Is 5,000 mm waterproof enough for a tarp?
Yes. A 5,000 mm rating is fully waterproof in rain; rain puts far less pressure on fabric than pooled water or wet snow, and the AquaQuest Safari, Guide and Survivor are rated to 5,000 mm with every seam taped.
What does the Defender's 20,000 mm rating mean?
The Defender's 70D nylon with its heavy TPU coating is rated to hold back a 20,000 mm water column, four times the 5,000 mm of the Safari, Guide and Survivor, which is margin against pooled water, wet snow and years of wear.
Do I need to seam seal an AquaQuest tarp?
No. Every seam on every AquaQuest tarp is taped at the factory, and the Defender's seams are heat-taped.
Is the AquaQuest Defender ripstop?
No. The Defender is 70D nylon with a heavy TPU coating; the Safari (70D), Guide (40D) and Survivor (70D) are ripstop nylon.
What does 70D mean on a tarp?
The D is denier, the weight of a fixed length of yarn; 70D is heavier yarn than 40D, which is why a Safari 10 x 10 (70D) weighs 1.7 lb and a Guide 10 x 10 (40D) weighs 1.3 lb with the same coatings and rating.
Related: Which AquaQuest tarp should I buy? | What size tarp do I need? | How to pitch a tarp | About AquaQuest | Waterproof Tarps | Bivies
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