Reel and Spool

Line-holding tools used to deploy a DSMB, run a guideline in a wreck or cave, or navigate back to a fixed point.

Reels and spools are how divers manage line underwater. A spool is a simple plastic or delrin disc wound with line and handled with a finger and a double-ended clip, while a reel adds a handle, a spindle, and usually a lock. Both exist for the same jobs: sending a DSMB to the surface, running a continuous guideline into an overhead environment, or laying a search pattern from a fixed point.

For DSMB work most divers prefer a small spool with 15 to 30 m of line, enough to shoot the buoy from safety stop depth or deeper with less mechanism to jam at the worst moment. Primary reels for cave and wreck penetration carry far more line and pay it out under light tension so the guideline stays taut and followable by touch in a silt-out.

Line discipline is the real skill: wraps and placements that keep the line off the bottom, tie-offs that hold, and never letting slack build. Training in guideline use is a core part of cavern, cave, and wreck courses.