The blood knot is one of the simplest fishing knots of all and while it weakens the line by around 40%.

Despite the obvious shortcomings it is still one of the most popular fishing knots for joining heavy fishing line that needs to be joined quickly.

Simply twist the two lines together then separate the center and pass one end through the center one way and the other tab end through the opposite way.

The blood knot is one of the most popular offshore fishing knots used by commercial tuna longliners.

Fishermans knots-Blood Knot

They tie up their 4 millimetre thick 800 pound breaking strain longlines with this knot as it pulls up easily even on very heavy monofilament nylon fishing line.

For the strongest results put as many twists in as you can without causing the nylon to grab when setting the knot.

The maximum number of twists possible will vary considerably between nylon brands and lubrication used.

Tuna fishing knots

We advise recreational fishers that want more reliable fishing knots for tuna to check out the crimp join featured here