Tension is everything — slack braid mid-weave = wraps loosen = knot slips under load.
The test: pull HARD. If it slides, not enough wraps or a loose weave. Re-tie, don't hope.
Tie at the house. On rocks at night, use the double-uni (next page) and fix it properly later.
Practice with the 40 lb spool — thick line teaches hands faster than thin.