Dyneema tarp weight. Why is dutchware heavier than Hammockgear?

[geirface]

I'm looking at the 12feet dyneema hex tarps from HammockGear and Dutchware. Can someone explain to me why the Dutchware is 43% heavier?

The HG weighs 5.55oz (157g) while the Dutchware is 225g according to the web sites. It looks like it's the same material and the same size. The lightest one (HG) even has a side panel pullout as standard, which makes it even more suprising that the Dutchware is more heavy; Even without the side panel pullout.

What am I missing here?

And please tell me if this was the wrong place to ask this question. I'm new to the forum.

[Otter1]

Best guess is the cut - HG uses catenary cuts, Dutch does not. Seems like a lot though.

[Rolloff]

It's a postage stamp!

[jeff-oh]

looking at the two listings it prob. comes down to how the weights are calculated. Are the weights calculated or measured? If measured, is it the average of several tarps?

Does DWG quote the entire package, tarp, stuff sack etc. Does HG only quoted the tarp alone or perhaps just the fabric used? Is there rounding error in the numbers? One difference is DWG uses larger attachments at the ridgeline. Though this would only account for ~4g max.

HG quotes their fabric at .50 oz./yr^2 where DWG quotes .51oz./yd^2. Though the fabric is only made in the one weight and quoted at .51oz/yd^2 by Rip stop BTR.

Best thing to do is ask each company on their company forum page on this site. They are both active here and may explain how they get their numbers.

[Just Bill]

Occam's razor: Likely there is a typo or busted calculator.
I think this came up before but can't recall who was at fault so....

Roughly speaking- Ignoring any cuts:
A 12' long in a rectangle... 12x12= 144 inches. Two panels (sides)= 288 inches
standard width is 54" per panel (8'6" wide) so 288x54= 15,552 sq inches of material
There are 1296 sq in per yard. 15552/1296= 12 yards on the nose.
12 yards x .51 ounces per yard- (12x.51=) 6.12 ounces.
Probably a bit of seam allowance in there on the length but at these fabric weights call it 6.25 ounces and move on.

Neither vendor is silly enough to use heavy webbing in lieu of grosgrain or to apply edge binding so for the most part the notions should be similar in weight.
Reinforcing, seam tapes, adhesives, and whatever... adds up fairly fast when the fabric is so light... but should be in the ballpark of each other too.

Checking the flat rectangle tarps on each site-
Hammock gear- Weight for Green 12' x 8'6" = Approximately 10.02 ounces (284 grams)
Dutchware- Says 283g with panel pulls- if you select the options.

Just for fun- Zpacks 8.5' x 10' flat tarp is
Weight 7.1 oz / 200 g multiply by 1.2 for 12' long and you're at 8.52 ounces.
Still makes sense to me as they are a bit tighter on their grosgrain use/tie out reinforcements and absolute SUL customer base.

Long story short- looks like the Hammock Gear under 6 ounce weight on the site is a typo or busted calculation and Occam's human error once more shaves the day.

[geirface]

I emailed the two companies before I posted the question here. The answers were:

Dutchware: "We don't know all of the details on how the Hammock Gear tarp is made, so we can't be sure why there is a weight difference."

Hammockgear: "I know Dutch uses different hardware on the ridgeline, but other than that I am not sure. It must be something in the way they construct their tarp, the weight of the grosgrain tabs he uses or possibly his website numbers aren't correct?"

[cmoulder]

I don't know if this has anything to do with it, but some years back I read somewhere (sorry, googled it a bit and couldn't locate it) that because DCF (originally Cuben Fiber) was almost exclusively used for sails, DCF weights were (are?) calculated for a "marine yard" which is something like 36"x28". Whether this applies or not, I have no idea.

However, if someone were using those numbers to calculate 36"x36" then the weight would come in lower, and a direct measure would of course be higher. That's why I like to use a good scale with 1g or 0.1g resolution.

[Papasmokes]

I've wondered this as well... Could be the cut of the tarp? But it seems like a big difference for sure

[tlfillingim]

Occam's razor: Likely there is a typo or busted calculator.
I think this came up before but can't recall who was at fault so....

Roughly speaking- Ignoring any cuts:
A 12' long in a rectangle... 12x12= 144 inches. Two panels (sides)= 288 inches
standard width is 54" per panel (8'6" wide) so 288x54= 15,552 sq inches of material
There are 1296 sq in per yard. 15552/1296= 12 yards on the nose.
12 yards x .51 ounces per yard- (12x.51=) 6.12 ounces.
Probably a bit of seam allowance in there on the length but at these fabric weights call it 6.25 ounces and move on.

Neither vendor is silly enough to use heavy webbing in lieu of grosgrain or to apply edge binding so for the most part the notions should be similar in weight.
Reinforcing, seam tapes, adhesives, and whatever... adds up fairly fast when the fabric is so light... but should be in the ballpark of each other too.

Checking the flat rectangle tarps on each site-
Hammock gear- Weight for Green 12' x 8'6" = Approximately 10.02 ounces (284 grams)
Dutchware- Says 283g with panel pulls- if you select the options.

Just for fun- Zpacks 8.5' x 10' flat tarp is
Weight 7.1 oz / 200 g multiply by 1.2 for 12' long and you're at 8.52 ounces.
Still makes sense to me as they are a bit tighter on their grosgrain use/tie out reinforcements and absolute SUL customer base.

Long story short- looks like the Hammock Gear under 6 ounce weight on the site is a typo or busted calculation and Occam's human error once more shaves the day.

To add to that, we can take into account the cuts.

The best I can find on Google, the bottom edge of the tarp (parallel to the ground) is 78".
132" (11ft ridgeline) cut to 78" means we remove 54" on each side.

That means on each corner of the rectangle, we remove a triangle of 27x54 (54/2 x panel width). .5xbxh = .5x27x54 = 729.
729x4 = 2916 sq in removed from the cuts.
This means 20% of the material is removed by the cuts 14256-2916 = 11340 sq in.

11340/1296*.51oz/yd = 5.61 oz of material, which is more than the 5.14oz listed on their site as of now.