Skyscape X -minor mods.

You have a problem. The polycro groundcloth s sticks out beyond the tent all around. This will collect water and let it run under the floor. (Don't ask…)

SOLUTION: Cut the ground cloth 2" smaller than the tent floor perimeter.

Definitely what Eric said. Your ground cloth should be a few inches smaller than your tent all around.

Yep, of course.

… what eric said… would be a legit issue of the Skyscape X had a silnylon floor. As it is, all the water that wants to can collect under there and big'flipping'woopie'doo… its a cuben fiber floor and thus highly unlikely the weight of Shane and his bag/pad are going to be enough to cause enough pressure to force the water through 0.74 cuben fiber fabric. Yeah, it would make sense doing it for when it is time to break down and pack the shelter, but if you are doing it strictly to keep water out, its obviously totally unnecessary for him to go back and cut down and redo all of his holes and such at this point, for the reason explained above.

I gotta say, I do not get the whole issue with the head-end modification… simply throwing my ditty bag at the head of the shelter when I first get inside pretty much solves that whole issue.

Question: why not use an extra two grams of cordage and length it out to the primary stake rather than use another stake(???) No way an extra foot of cordage is going to weigh more than a stake, and should not affect the structural support of the SMDSX in any way.

Unrelated… it would be nice to see SMD go with a heavier weight fabric for the bathtub floor so we would not even need the extra ground cloth.

ps… I posted a photo a week or so ago about the next generation of the SMDSX… it will have external support rather than internal support. The cross bar will also change to a carbon fiber and have the double side entry that the most recent generation has.

Thanks John, I was pondering guying it out to the main stake, I still my do so.

Does the Skyscape X have attachment points for guylines at the tops of the poles, to keep it steady when the doors are rolled right up? ….. or for very windy conditions?

No, it doesn't. But it is surprisingly stable with both sides rolled up.

"… would be a legit issue of the Skyscape X had a silnylon floor. As it is, all the water that wants to can collect under there and big'flipping'woopie'dooits a cuben fiber floor and thus highly unlikely the weight of Shane and his bag/pad are going to be enough to cause enough pressure to force the water through 0.74 cuben fiber fabric."

So Richard tests the stuff to death, posts the results at enormous length right here, showing ~3000HH for best quality silnylon that is much less expensive than the cuben that has much lower HH, elasticity and abrasion resistance, and the promoters still say cuben's more waterproof and the newbies still believe it. Kind of like politics. Is there any hope? Not so much.

Samuel C. Farrington: So Richard tests the stuff to death, posts the results at enormous length right here, showing ~3000HH for best quality silnylon that is much less expensive than the cuben that has much lower HH, elasticity and abrasion resistance, and the promoters still say cuben's more waterproof and the newbies still believe it. Kind of like politics. Is there any hope? Not so much.

Sigh, stop trying to make flamewars where none are even remotely present.

As Jim said above… it does not have attachment points for guylines.

However, with the next generation of the Skyscape X using an external support system, it might be possible to attach some cordage around the top of the poles (???)… gonna have to wait and see what the final product design is like, but that would be sweet to have an extra two guyline tieouts on the sides to give some extra strong wind gust support. Max I have had my Skyscape X was around 38mph gusts and it held fine. I think by simply having the supports on the outside will mean a fair amount more strength (less chance of them slipping) but yeah, if there will be a way to attach a secondary guyline to the top of them, that could help further push the boundaries of side-wind support, eh!

I might be stepping on a landmine here because I'm not sure where the flame is but …

I have a heavier weight CT5K.18 cuben floor and it leaks like a sieve. It has tiny pin holes from nothing more than normal abrasion and from the "natural" folding/creasing that occurs when it is packed (I always roll it to try and minimize this effect.) There are enough of these pin holes and they are so small that it is difficult to track them all down and effectively patch. Mind you, I treat it like a baby and always use a ground sheet but alas, waterproof only applied to my cuben floor prior to actual normal use. I have had to strategically use a hole punch on my ground sheet to assure drainage, otherwise I could be swimming if something went wrong.

I personally will never get an attached cuben floor again.

Christopher: I personally will never get an attached cuben floor again.

Yeah, I hear ya. I am within the small but growing crowd that believe that CF has no place being used as a bathtub of a shelter. That is one of the things that has made the Yama Cirriform shelter so dang interesting. He was the first person to really find a way to get a CF top and a nylon floor (the holy grail of UL shelter). What he did to make it happen was pretty dang smart. I really look forward to other companies going with this same idea of using silnylon floor and cf top. Might seem odd and add an extra couple of ounces, but for the longevity of the shelter it just makes since, eh! Take for example the SMD Lunar Solo LE with freaking 70D Polyester for the floor… you could put that on just about any ground surface and never have to worry!!

John. In a word, No. You have a right to your opinions, and I to mine.
I agree with your last post, though, up until the 70D polyester.

Samuel, did Richard write about tests with .74 cuben? I remember reading his findings, but i thought it might be the thinner, lighter stuff, but am not sure.

Sam: I agree with your last post, though, up until the 70D polyester.

Is that because you just do not like SMD, or because of the use of PU?

I thought I remember reading something here at BPL a long time back that PU was the same basic strength of silnylon but that it had a higher pressure pass-through, making it better at allowing water to get pushed through from the pressure of laying on it all night. Do I have my fabrics backwards in regards to that??

Hi John

> PU was the same basic strength of silnylon but that it had a higher pressure pass-through,

Not quite right. A PU-coated fabric has about half the tear strength of silnylon (or maybe less). It's to do with how the PU coating focuses the forces onto just one thread at a time while the silicone coating spreads the forces over many threads at a time.

On the other hand, a PU coating usually has a higher HH than silnylon. Mind you, some of that is due to the coating plants thinking that 1500 mm HH is sufficient. It is – for a roof, but NOT for a floor.

A PU/Si coated fabric is an interesting combination. We may get to see more of this.

Yeah, leaking pinholes in the Cuban, due to cracks in the Mylar film. Now a KNOWN problem, brought to you by BPL and Richard Nisley and others. Which is kinda funny timing, as some of the mainstream tent companies are just getting into Cuban!

Cheers

@Roger,

Thanks for the clarification. It was something you wrote a long while back that I remember reading about SN/PU that I guess my brain stored the data backwards on.

So, PU does better at keeping the water from pushing through, but silnylon does better as being just all around tougher.

The PU/Si fabric you mention… how does it compare to the regular fabrics in regards to weight? It is going to be so far over the top heavy that it won't have any viability of making it into the market?

I'm using PU nylon self coated on the reverse side with MYOG silicon for a bathtub floor. Seems tough enough. Adds weight though.

Edited
It was about 15d sil/pu fabric (several manufacturers use that) but it had little to do with the OP.

John,

PU/sil coated fabrics have been around for sometime now. They are used extensively in a number of tents and tarps. They are used primarily by the more mainstream tent manufactures because it allows you to use the lighter fabrics and still do seam taping. The coating is PU on one side and Sil on the other.

We don't use this fabric as our seams are too complex to be seam tapped anyway. Because of this, we can't seam tape the main seam of our PU/polyester tents.

Also, while I've not heard direct reports, I suspect that the PU/Sil coated fabric still has the same old issues of flaking coating, mold and mildew, etc. So we'll stay away from them for the time being.

As to what makes the best floor for a tent. Well that's pretty much anyone's guess. There is currently no perfect fabric. Especially if you're dealing with extremely lightweight tents.

Is Cuben Fiber better than Sil-nylon? Well the answer is both yes and no. The issue is learning how to get the most out of any fabric that's used. This includes where to set a proper camp, how to treat gear, etc.

If you are rough on gear or seeking a bit of extra protection. I do think that a ground cloth is a good option under a Cuben floor. Recently I suggested to someone that they cut down a polycro ground cloth to size and simply tape it to the underside of the floor. That way it's always there, will last a number of outings and is easily replaced. Weight wise, it probably adds less than 2 ounces.

As to the best material for HH. I do know that with new material our Suter tester results place cuben with a significantly higher HH than any of the sil-nylon than we use, both foreign and domestic. Currently we use 40D sil in the floors of our shelters and 30D in the canopy.

I realize that the difference between new and worn fabric can be quite different. However at the moment, I don't know of test method that would apply equal wear to the different materials so that a valid comparison can be made.

John,
Re: "Is that because you just do not like SMD, or because of the use of PU?"

I am fine with SMD, and think their designs are very innovative. Not sure if you are right about them using 70D polyester for a floor, but I would go for 3000mmHH silnylon, such as sold by Thru-Hiker, Terra Nova or Lightheart Gear, for a floor over 70D polyester because of the silnylon's strength, elasticity, and resistance to water and abrasion. The one catch is the silnylon floor must be stretched taut over the ground. Otherwise, no matter how much silicone is applied to the inside, the outside will slip over the ground and bunch up under you.

This is not a problem for me, as I have to pitch on a level spot to sleep OK, and because I use dome tents with an arced carbon fiber pole frame that holds the floor taut at the corners, or as Roger likes to call them – "Pop-Ups." Even the best silnylon sags a little, and the frame keeps the roof up where it belongs, and I like a frame in high winds in case a stake might loosen. Just a personal preference.

You are right about me not liking the use of PU, because as Roger points out, it weakens the fabric considerably. It is also heavier, at least the PU I've seen.
I've been trying to get more info about the newest Porcher-Sport PU coatings for very light paraglider nylon fabric, but so far without success. Still working on it, though.

Justin,
I think Richard tested just about everything available. (One of us could look it up.)At that time the half ounce and 3/4 oz cuben had the same thickness of mylar on the outside, denominated by a suffix of ".18." Ron Moak's post does not specify HH numbers of the cuben and silnylon he uses. Maybe someone will provide some current numbers.

"gotta say, I do not get the whole issue with the head-end modification… simply throwing my ditty bag at the head of the shelter when I first get inside pretty much solves that whole issue." John Abela-

John- One if the reasons I did the head modification was in partial consideration to your excellent review of the Skyscape and the netting in windy situations.

From your review-

"•Loops on the outside of the bathtub side-wall where your head is at. The idea of these loops would be so that you could use a couple of stakes/sticks (or cordage out to the primary side stakes) to pull out the netting right where your head is at. When its really windy the sides of the netting tend to flap around, and can even flap into your face if you are not using a sleeping pad. Rather annoying and could be so easily solved."