One of the most popular knots for tying two lines together has to be the double grinner.
Here’s a close-up on how to tie it, as seen in Rod Hutchinson’s column back in August 2002.

One of the most popular knots for tying two lines together has to be the double grinner.
Here’s a close-up on how to tie it, as seen in Rod Hutchinson’s column back in August 2002.