I’m making a tarp!

4mx4m is a large tarp that will experience very large forces in high winds … it will need to be well made.

regarding your two questions:

To make the tarp I’ll join three 4m x 140cm strips along the long edge. Should the joins be reinforced?

A carefully made flat felled seam should be plenty strong

What would be suitable tie-out point reinforcement material or approach for a tarp of this size?

Glue a semi-circular patch of the same material to the edge of the tarp, fold over twice and sew on the guy line loop, as shown here (apologies for the shameless plug:-)

Since your three panel tarp will not have a seam down the middle you might want to strengthen the ridge line by gluing 1 or 2 layers of 1 inch strip down the middle for added strength there.

Alternatively, you could use construction techniques used on Cooke Custom Sewing Tundra tarps … these evolved over many years serving canoe expeditions in the far north (no wind breaks for hundreds of miles). Sew nylon webbing around the entire perimeter and sew loops to that. Also sew nylon webbing on the underside of ridgeline.

http://www.hammockforums.net/forum/showthread.php?t=39108

Post I made on "Hammock Forums" yesterday. This tarp is 11.5 feet on the ridge and 4.5 each side.
R

Hi Chaps,

Thanks for the replies and advice.

Very useful and the CCS approach looks simple enough and I'll likely try that for starters.

Kelsey

Jim,

If he goes the CCS perimeter webbing route, what width would you recommend? I'm guessing that a ULer would want minimal webbing (3/8"?) for a smaller 1.1oz silnylon tarp rather than the 3/4" webbing on the CCS tarps.

Just hem the perimiter – fold over twice and do one row of stitches

If he goes the CCS perimeter webbing route, what width would you recommend? I'm guessing that a ULer would want minimal webbing (3/8"?) for a smaller 1.1oz silnylon tarp rather than the 3/4" webbing on the CCS tarps.

Hmmm …. I'm thinking that the size of his tarp (4m x 4m) pretty much takes him out of the UL realm.

I made a 3mx3m (10×10 ft) group cooking/eating/hunkering tarp about 5 years ago … used 1" grosgrain ribbon around the edges and for guy line loops. It's stood up to winds that sent 70lb aluminum canoes airborne so I suppose that's a reasonable test. Note that 4mx4m is almost twice the size of 3mx3m.

I'm confident that minimally sized webbing or grosgrain would be fine for a solo sized tarp … but I don't think I'd bother, glued or sewn reinforcing patches are perfectly adequate for a small tarp.