Topic

Help my half-pyramid pitch

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PostedMar 15, 2008 at 4:30 pm

I see the beautifully pitched tarps on MLD’s site so I know its possible, but I can’t seem to do it myself.

From the picture on Ron’s site and other pictures I’ve seen around here, it is possible to pitch a flat tarp in a half pyramid configuration and have all four corners staked straight to the ground and still retain a rectangular shape.

Whenever I try to pitch my 5×8 poncho-tarp this way, I stake the backside long edge out taut, then put the trekking pole in the middle of the opposite long side. When I try to stake out the remaining two corners they end up wrapping around towards the pole and making for a small space in which to enter the shelter. Instead of the short sides being parallel to one another, they “toe-in” towards the pole.

If someone would be so kind as to clue me into what I’m doing wrong I would really appreciate it. Pictures from multiple angles and the height of your trekking pole would also be helpful.

Thanks in advance.

Adam

PostedMar 15, 2008 at 4:49 pm

The size is the key, I bet the tarp on MLDs site is bigger than 8×5. If you lowered the apex of the half pyramid you would be able to get a parallel pitch but it would probably be too low to be much use. Notice the pictures of the smaller tarps are in a lean-too configuration on the site.

PostedMar 15, 2008 at 5:35 pm

The lower the tarp is pitched, the less the "toe in"

If you don't want any toe in at all, you will have to get a tarp that isn't a rectangle when layed flat. The side of the tarp that is the opening has to be longer than the backside.

John G BPL Member
PostedMar 15, 2008 at 6:17 pm

There has to be toe-in since the length to go from corner-stake, up and over the pole tip, to corner-stake must always be longer than just going straight from corner-stake to corner-stake.

The tarp in the picture is labeled 5.9 x 9 (so it's just a little bit bigger than your tarp). Also, the pole looks like a 2 section pole with 5 tick-marks showing. On my 3 section poles, 5 tick marks yields a 32" long pole with bottom section fully collapsed. But since MLD sells optional 28 and 42" tarp poles, I'd be willing to bet it's the 28" pole. Especially since the sleeping bag is laying in a slight depression (especially visible on the left at the foot of the bag, and by noting the shadow under the rear edge – which is about 3-4 inches off the ground).

I also believe the picture is somewhat hard to see the geometry in… First, the picture is taken using a wide angle lens from very close and at an upwards angle (look closely at what's in focus the most, the shadow lines and minor distortions like how the guy-out line appears about 1/3 thicker at the bottom of the picture than at the top near the handle). The end result is that things in the foreground (like the front corners of the tarp) will appear slightly bigger and tend to hide some of the toe-in.

Also the right side has a little bit of toe-in in the picture, but the left side has much less. However the left side as a 1-2" high wrinkle on top near the rear fold, but the right side is smooth. Taking out this wrinkle would probably add an inch or two of toe-in to the bottom edge of the left side.

Overall, I think MLD's picture is great for showing the pitch technique and space from the "inside the tarp" view – and not "tricky photography". But I can see how these few little things might hide 2-3" of toe-in.

But is toe-in bad ? Or just more wind-shedding :)

Cheers.

PostedMar 15, 2008 at 6:33 pm

I thought some "trick photography" might have been involved :). I've been practicing it quite a bit and had sort of come to the conclusions that you all have verified. I just wanted to make sure that I wasn't making some obvious mistake that was holding me back from a slightly better pitch than what I've been getting.

Thanks!

Adam

Ron Bell / MLD BPL Member
PostedMar 15, 2008 at 6:56 pm

Hi,

MLD Monk Tarp pic is with a adj. trek pole set to about 35". … reg 70mm lens-nothing to throw off perspective…. The pole height is the key for the nice half pyramid shape. The 6' wider roll silnylon helps.

The sides do form close to 90 degree with the rear side. If the pole is too tall then the sides end up pointing is more at the front- the "toe in" effect.

With a smaller rectangular tarp, 5.2X 9 (a "reg" size silnylon) you would need to set the long ground side a few inches or more off the ground by using short corner guy lines so you would have enough room underneath. Then the sides can remain fairly straight and you would have enough room under it. The few inches off the ground pitch and the short guylines substitute for the lack of enough width witout having to set the pole height too low.

Smaller (mainly narrower) rectangular tarps can work OK in a modified half pyramid…lots of possibilities to play with.

Viewing 6 posts - 1 through 6 (of 6 total)
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