Update: cutting my scrub time in half with a $12 kitchen timer clipped to the harness
Kept blowing past my bottom time on the last two jobs at the Galveston dock because I can't see my watch through the mud, so I zip-tied a cheap mechanical timer to my BC and set it before splash. Sounds dumb but my last three dives came up within 2 minutes of plan, so what are you all using for bottom time when visibility is basically zero?