Just wondering if many people go this route rather than a full flat fell.
Just to be clear this is what I'm talking about:



The top drawing is what I'm calling 'semi-flat fell' and the bottom is what I think most people on here mean when they say 'full flat fell'
The red lines are each a stitch.

Anyways, it doesn't seem to me that the full fell would be much stronger because that one stitch is still only going through two layers of fabric....
I'm going to be making a pyramid tarp next week-ish and feel like I can probably get nicer seams with the semi-flat fell, but if they're not as strong I'll do something else.

Tell me what you think.
Thanks

I guess it's worth mentioning that I couldn't care less how it looks, so those 'rough' edges are fine.
And either way, the smoother side of the seam will be on the outside.

If I go with the semi-flat seam, do you think it'd be worth it to seam seal the inside as well for extra strength?

Would the exposed raw edges tend to come unravelled in the semi-flat felled seam?

The semi-flat felled seam has one (or two) less layers of fabric which can sometimes be important, like if you had to sew through them.

I've always just used the regular flat felled seam

I really don't think coated fabrics unravel like uncoated ones.
Or atleast I've not noticed any of the silnylon I've used unraveling.
I'm just going to get with the semi-flat felled and hope for the best.
I'll make a post once I'm finished and tell people how I feel about it.
Thanks