Working on that old bridge in Mobile and the current was way worse than the charts said

We were doing an inspection on the pilings, and the flow meter said 1.5 knots, but it felt like double that... my umbilical got wrapped around a crossbeam in about 30 seconds. Had to cut and do a free ascent, which was not the plan. Now I triple-check local conditions with the boat crew before I even gear up. How do you guys handle jobs where the water movement doesn't match the reports?

3 comments

3 Comments

jakejones2d ago

Yeah, that "free ascent" part got my attention. I'd be freaked out too. I always ask the boat guys to run their own flow check right on site with a drogue, not just go by the printed charts. Those things can be way off if the wind's been blowing hard upriver.

evan_green522d ago

How much current difference have you seen between the drogue check and the chart numbers?

mark_carr72d ago

Actually, the drogue check is for the boat's flow, not the current difference... it tells you how fast the water is moving past the boat when it's anchored. The chart numbers are for the predicted tidal current. So you're comparing two different things... boat speed over ground vs. the water's own predicted movement. They should be close on a slack tide, but if wind or recent rain has piled water up, they can be way off. That's why the on-site check is so important.