Fishermans knots-Blood Knot
Blood knots and blood loops are the most popular offshore fishing knots used by commercial tuna fishing longliners to tie up their 4 millimetre thick 800 pound breaking strain longlines because 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