Zero-Visibility Survey Basics With Passive Acoustic Tools

Zero-visibility conditions are treated as survey-ending events in standard cave diving training. EchoQuilt uses passive acoustic tools to keep the survey productive when sight fails. This primer covers the fundamentals for teams transitioning from line-and-tape to sound-and-motion workflows.

The standard answer to zero-visibility in cave diving survey training is to not be there. NSS-CDS Cave Courses require zero-vis exit drills with blackout masks as a safety rite, not a survey technique. Trainees practice following line by feel while reading tactile markers — Dorff arrows, line cookies — to navigate out. Nothing in the standard curriculum teaches a diver how to produce usable survey data in a blacked-out passage. The survey is over; what remains is the exit.