The offshore swivel knot is used to connect a swivel to a double line. 3 loops for more than 50 lb line, 4 loops for 30 lb – 50 lb line, 5 loops for 12 lb – 30 lb line, 6 loops for less than 12 lb line.
Based on the step-by-step illustrations in the Sea Fishing Knots And Rigs book:
UK https://www.amazon.co.uk/dp/B09ZLVWMPV/ref=cm_sw_em_r_mt_dp_GDRK9BA3S2WYR2NBVDEC
USA https://www.amazon.com/dp/B09ZLVWMPV/ref=cm_sw_em_r_mt_dp_6P37PHQ0861RXZZ8FFMJ
@Angling Knots