Monday, May 27, 2024
HomeDiving EquipmentsLines And Markers, Used For Under Aquatic in SCUBA Diving

Lines And Markers, Used For Under Aquatic in SCUBA Diving

Scuba Accessories | Lifeline’s | Buddy Lines | Swim Diver’s Marker | Lost Diver Marker (LDM) 

When conducting attended diving, the diver is always to have a lifeline, or gas umbilical designed to attend as a lifeline firmly attached to their equipment and attended at the surface. The lifeline for the self-contained diver should normally be 8 mm of man-made fiber. The diameter of the line will vary for the type of work for which it is planned.

On each event of use lifelines are to be inspected for damage and faulty lines improved. The distance between markings should be checked occasionally, particularly on new lines that are stretching, and the marks adjusted as required. The diver is responsible for securing their lifeline. The attendant is to check that the inboard end is confidently secured on the surface.

Buddy lines

When two divers/swimmers functioning in SCUBA diving are being prepared to operate as a pair, a buddy line is used to link them together.  The buddy line should be attached to either the arm/wrist, which will allow the set to be ditched if necessary, without it becoming foul. Buddy lines are to be thoroughly examined at consistent intervals for signs of decomposing of the line or stitching or any other signs of weakening, and the dive team leader / in charge of diving operations is to satisfy themselves on each event of use that the buddy line is properly attached to the swimmers and acceptable for use.


Swim Marker for SCUBA Diver’s 

Swim Markers are surface floats used to designate the position of a diver. To keep the float line clear of the swimmers’ feet a 50 mm apple-ring float can be fitted on the line by taking a round turn through the hole in the float, or a half-hitch above and below the float. The ring is then adjusted to a distance of 2 m from the swimmer. It should be noted that the float is only a marker and will not support the swimmer in the water and that the float line is not strong enough to lift the swimmer out of the water. By night an indicating light or chemical light (glow stick) may be fixed to the float. 

Lost Diver Marker (LDM) 

The requirement to have a lost diver marker is dictated by the task.

  • A ready-made item, it includes a 5 m distance line with a soft eye spliced at the end, suitable for a diver’s hand.
  • A light may be attached when diving at night or in poor visibility

The LDM is to be ready for immediate use during the dive should the Risk Assessment indicate so. Deployment is to be closely controlled to prevent possible injury to the lost diver. In fast water or strong tidal stream, the LDM may need to be replaced at an early opportunity with divers shot to provide a more secure datum. 


Overall, the proper use and maintenance of these lifelines, buddy lines, swim markers, and lost diver markers are crucial for ensuring the safety, communication, and coordination of divers during underwater operations and recreational SCUBA diving.

- Advertisment -

Most Popular