Any waxed cordage can self release a knot under tension.I have some of the last silk manila lariats (waxed,no splinters).Even these are slippery for emergency packhorse lashing.The trick is to throw a second lockstitch,ie double tie a square knot.Waxed thread is ideal for field mending(boots,tents,packs etc). I use a speedy stitcher,which duplicates a sewing machine stitch in a hand held awl.I can't find them online,but for a order form write STEWART MFG.,INC. P.O.Box 330 Northboro,Ma 01532-0330. They are pretty common in feed/tack stores.Dixie Gun Works sells an excellent artificial sinew, www.dixiegun.com.<br><br>