A simple change to my pre-dive checklist cut my bottom time on a murky job by almost half

I was on a salvage job in the Mobile River last month, visibility was maybe two feet on a good day. We were down there feeling around for pieces of a sunken barge, and my first two dives I came up with nothing. My dive partner, this old guy named Carl, asked me how I was searching. I told him my usual grid pattern. He said, 'In this soup, you're just swimming in circles. Mark your start point with a big glow stick on a weight, then tie a 50-foot line to it. Swim out until the line goes tight, feel around, then come back to the stick and move it over ten feet. Repeat.' I started doing that the next day. Went from finding zero pieces in a four-hour dive to pulling up three sections in just over two hours. It seems so obvious now, but having that fixed reference point in zero viz changed everything. What other low-vis search tricks do you guys use when you can't see your hand in front of your face?

3 comments

3 Comments

cole54916d ago

Glow stick trick is solid. We do something similar with a clump weight and a jackstay line. Lets you sweep an area like a lawnmower. In total blackout, I'll just go by feel and sound. Your exhaust bubbles hit stuff overhead, you learn to listen for that. Sometimes you just have to get muddy and crawl.

alicecraig15d ago

Mobile River salvage sounds intense. That glow stick method seems like overkill for most low viz dives I've done though.

nathan10015d ago

Read about a team using those chemical light sticks on a car recovery in a quarry. Pitch black down there, guess it makes sense.