Artificial sinew is typically used (its a heavily-waxed flat polyester cord) although many other things can be utilized.

Dacron (polyester) "squidding" line is sometimes used, but I've always seen it coated with epoxy after the lashings have been made (i.e. on the Dyson baidarkas, and some of Tom Yost's kayaks).

Hemp and linen cord is sometimes used in Europe, although I think both are waxed.

I don't know what is used in Greenland - probably whatever is easiest to get at the time of building.

I have some nylon cord (twisted strand, 0.050", 80-lb breaking strength) used for upholstery (tufting) that I'm going to use for my current build. Only issue I see is the ends fraying, but cutting with a hot knife will take care of that.

Waxed cord might be a bit easier to handle, but the wax won't make any funtional difference.

You'd want to stay away from anything that can rot, though. Nylon should be fine, but it needs to be capable of having a lot of tension put on it (i.e. relatively high breaking strength). 'Thread' sounds like it might be too light duty for lashings...

: Will nylon upholsterer's thread suffice for lashing or should I use something
: else? Also does it have to be waxed?