It’s not necessary for zero visibility alone. It’s only in situations where there’s zero visibility, the navigation is accessible from both directions, and people are actually doing that, that it could have any effect at all.Thanks all for the thoughtful recommendations. For the record, I decided to do the following:
While I agree that 0 viz is unlikely in the kind of diving I do, it doesn't take much effort to drill holes and it doesn't take functionality away from the markers (e.g., I don't like adding zip ties because it may make staking markers more tricky).
- Name and progressive number with a permanent marker for ease of note taking
- Drilling holes for 0 viz identification
- Adding some reflective tape to increase visibility from a distance in good visibility
If there are cookies on only one side of the T, you don’t need to identify your specific NDM (other than by team order) to figure out the correct exit. As long as that’s clear, the only potential issue is trading cookies at the surface after the dive. I don’t have a problem with people customizing their NDMs, but this feature is absolutely oversold. It feels more like a rite of passage for new cave divers than a meaningful addition to safety.