Distance line

"guide line" redirects here. For other uses, see guideline (disambiguation).
Distance line
50 metres of line on a reel
Other namesguide line, cave line, wreck line, penetration line
UsesUsed to guide divers back to a specific point
Related itemsJackstay, jump line, search line, down-line, upline, messenger line
Cave diving guide line reel

A distance line, penetration line, cave line, wreck line or guide line is an item of diving equipment used by scuba divers as a means of returning to a safe starting point in conditions of low visibility, water currents or where pilotage is difficult. They are often used in cave diving and wreck diving where the diver must return to open water after a penetration when it may be difficult to discern the return route.[1][2] Guide lines are also useful in the event of silt out.[3]

A cave diver running a distance line into the overhead environment to facilitate a safe exit

Distance lines are wound on to a spool or a reel for storage, and are laid in situ by unrolling.[4] The length of the distance line used is dependent on the plan for the dive. An open water diver using the distance line only for a surface marker buoy may only need 50 metres (160 feet), whereas a cave diver may use multiple reels of lengths from 25 ft (7.6 m) to 1000+ ft (300 m).

Reels for distance lines may have a locking mechanism, ratchet or adjustable drag to control deployment of the line and a winding handle to help keep slack line under control and rewind line. Lines are used in open water to deploy surface marker buoys and decompression buoys and link the buoy on the surface to the submerged diver, or may be used to allow easy return navigation to a point such as a shotline or boat anchor.

The material used for any given distance line will vary based on intended use, nylon being the material of choice for cave diving.[4] A common line used is 2 mm (0.079 in) polypropylene line when it does not matter if the line is buoyant.

The use of guide line for navigation requires careful attention to laying and securing the line, line following, marking, referencing, positioning, teamwork, and communication.[3]

  1. ^ Cite error: The named reference Exley was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference Guideline 2 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Guideline 3 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Guideline 1 was invoked but never defined (see the help page).