Serving many purposes, a heaving line should be considered essential equipment on all dive boats. A light, flexible line that can easily be thrown with – after practice – great accuracy, a heaving line can be used as a messenger when passing heavier mooring lines between a vessel and the shore, or quickly deployed and thrown to a diver in distress on the surface; allowing them to be towed quickly back to the boat and safety.
Best made of natural, well-stretched 3 cm cordage about 30-metres in length, one end of the heaving line should be weighted to give it greater accuracy and throwing range when used against the wind. Although it’s often commonplace to weight the end with some heavy object, consideration should always be given to the effect that being struck with the weighted end might have on a potential victim.
The usual method of weighting the end is to construct a heavy knot known as a Monkey’s Fist. Using almost 3-metres of the line, a Monkey’s Fist is made by first winding three turns around the hand. Next wind a second set of turns across and around the first three, and then pass a third trio of turns around and across the second three but inside the first set. When the knot is correctly made, the end will come out alongside the standing part of the line.
To finish the knot, work all of the parts taut and then either splice the end into the standing part of the line, or tie an overhand knot, tuck it inside the Monkey’s Fist and then work all of the parts taut.
A lighter-weight – and quickly made – alternative to the Monkey’s Fist is the Heaving Line knot. Forming a bight with about 2-metres of line, begin frapping the end round both parts of the bight, about 10-cms from the actual bend of the bight, and continue until it is all but expended. Then pass the end through the small remaining loop and haul taut on the standing part of the line.
When throwing a heaving line always remember to secure the standing inboard end of the line fast to the boat. Nothing is more embarrassing than, having cast the weighted end of the line with pinpoint accuracy, to see the unsecured end slither over the side. Although there are several variations on the method of throwing a heaving line, a standard principle is to carefully coil about 18-metres of line in the left hand using rather small coils. Take about 6-metres of that line, (with the weighted throwing end) into the right, or throwing hand, and cast it with a straight arm, allowing the coils in the left hand to run out freely.
Often stowed in plastic buckets in order to keep them out of the way of a busy dive deck, heaving lines should be regularly laid out and inspected and then carefully coiled so that they will run free when quick use is required.