This isn't always possible to do, given conditions
and some ropes --which at least make things difficult
in producing a lot of tension--,
but you can make one nipping turn / half-hitch
along the line and then put in a rolling hitch beyond
that --the initial turn gives you some freedom to tie
the more involved knot. And this can be done with
the essentially just the one leg of a long bight,
the other being left to follow along in the wrapping
limply, until making the finishing half-hitch to close
the rolling hitch.
--dl*
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