What is Length in Meters?
Underwater cave lengths are determined by a knotted guideline or tape survey. Each method has its own advantages and disadvantages. A tape survey determines the distance between survey stations utilizing a plastic measuring tape. A knotted line survey employs a guideline that is knotted at fixed intervals — normally every 3 meters for an SI survey, or 10 feet for an Imperial survey. This technique allows a caver to explore a new passage while maintaining a continuous guideline to the cave exit. During the exit a surveyor counts knots (full intervals), while estimating any fraction of knotted intervals encountered between survey stations. Of course there is a bit more to surveying a cave than just knowing the length between survey stations! We post lengths for cave systems that are valid cave systems, according to international protocols. Authentic underwater cave systems must allow a diver to swim to any point in the system without passing through an open water (direct access to the s
