Page 108 - Peter Randall "The Craft of the Knot.."

Whereas the Fisherman’s Knot and Double Fisherman’s Knot make a
bend by tying an Overhand Knot around each other’s standing part, this
excellent bend, called the Double Uni-Knot or the Double Grinner Knot,
uses four or more Overhand Knots. The Double Uni-Knot is great for
joining fishing lines.

STEP 1 Overlap the ends of two ropes and use one end to tie a multiple

Overhand Knot around the standing part of the other line.

STEP 2 Tighten down, as shown.

DROPPER LOOP

Also called the Blood Loop, the Dropper Loop is yet another useful

fishing knot based on the series of Overhand Knots.

STEP 1 Make a Multiple Overhand Knot with four tucks.