Cat cut v. Straight edge

[SmilinJoe]

I am preparing to embark on my first tarp making adventure. I have most of my materials just waiting on some D rings. So I am curious what are advantages of the above other than weight? I am really excited to get my serious gang on other than in my back yard. Thx
Joe

[Brancher]

Cat cuts make it easier to keep the tarp pitched in a taut and smooth way by sort of 'balancing' the stresses better than straight sides -- and you don't really need a real deep catenary cut to achieve this. I use about a 3" deep cut over a 5-ft length and it works for me.

Check out the cat-cut calculators here - you can choose your length and depth, and they'll give a good template for cutting. Also might want to read this article:

http://www.jacksrbetter.com/a-few-words-about-tarps/

Hope this helps.

[SmilinJoe]

That does help, thanks Brancher
Joe

[Redoleary]

I'm a fan of the straight edge tarp, no cat cuts for this guy. The additional work and the reduced coverage (relatively speaking)of cat cuts give the straight edge tarp the advantage for me.

[Gqgeek81]

Grab the bottom edge of your shirt (assuming its not button up) and pull it tight with both hands just a couple inches apart. You'll see the edge of the shirt go nice and tight like it would if you pulled on a piece of string. Now do this with say ~10 inches between your hands. You'll see the edge flop over and is fairly slack. A lot of the tension has been deflected into the shirt and the tight portion of the fabric will be in from the edge some. (some of this is because the edge is a convex curve). This is sort of what happens with a normal tarp. On a windy day that edge will be flapping around like crazy. Cutting that edge into a curve allows you to keep it tight.

[nothermark]

A CATenary cut helps edge floppyness but precludes folding the ends in as semi doors in bad weather. I can stand using a few extra pegs over being wet and cold. YMMV. ;-)

[Itsamescott]

Like you, I am about to make my first silnylon tarp as well and debating about catcuts. I am not as concerned about the weight so that does not come into play but I do debate about the "floppiness" and the trying to do the more difficult catcut hemming.

Right now I am leaning towards making a full rectangle tarp and seeing how it goes. My thinking is that (1) it will be an easier first project with the unruly silnylon, (2) it would be more versatile to use when camping with the family and (3) I can always convert the rectangle to catcut later if I want.

[MattBigmonster]

One reason I won't go catcut for my main tarp. Straight edge work so much better in the porch mode, especially when all your ground dwelling friends use it


Catcut is good for solo trip.

[MDSH]

The flapping part left on, if one can stand the sound and motion of it flapping, has a chance of deflecting a few more drops of rain.

Plus, if you want to pitch one edge right on the ground, say, to get under the wind, then a straight edge provides a better "seal."

.

[kerryandjane]

You can still get a tight pitch on a straight edge. I believe the reason people started to cat cut was to relieve stress on the fabric while getting that tight pitch and to cut weight. A cat cut tarp is pretty one use.... But it'll make you more proud of the hard work you put in to make it.