Oh, yes, boaters do hit dredge pipelines, the Sea Tow Charleston owner warns.

So watch out out there.

Five dredges are or shortly will be at work in the Charleston Harbor environs, more equipment than has been out there at once in a long time. Three of them have laid piping — in Charleston Harbor to Shem Creek, offshore Folly Beach, and in the Cooper River near the Naval Weapons Station.

The piping “is most definitely a concern,” said Sea Tow owner Anthony Noury. “The increase of the volume of traffic in Shem Creek just in the past two, three years is tremendous.”

Dredging is the clearing of built-up material from channels or other waterways that need to maintain depths.

The lines particularly are dangerous at night when the only real distinguishing feature is a series of yellow strobe-light beacons set “sufficiently apart to clearly show the pipeline length and course,” according to U.S. Coast Guard regulations.

Most boaters who hit a pipeline just keep on going, so collisions are not often reported, Noury said. But he has towed boats after collisions.

In 2012, a Mississippi man was killed when something struck his outboard motor, slung it into the boat and struck him in the back, according to The Associated Press. He is suspected to have hit a plastic dredge pipe.

“When you’re in the vicinity of a dredge, use extreme caution. Behave like you’re in a no-wake zone,” said David Warren, Army Corps of Engineers project manager in the Charleston district.

Here’s where the lines are and what you need to know:

1. Dredge Cherokee

WHAT: Joint Base Charleston maintenance work.

WHERE NOW: Cooper River near the Naval Weapons Station.

CAUTION: Surface piping. Mariners are being alerted to current locations on VHS Channel 16.

2. Dredge Richmond

WHAT: Shem Creek deepening.

WHERE NOW: Charleston Harbor between Mount Pleasant and Crab Bank.

CAUTION: Surface piping running across Charleston Harbor from Morris Island, between the bank and Mount Pleasant, and eventually into the creek. Piping is submerged where it crosses harbor channels.

3. Dredges Bayport and Newport

WHAT: Maintenance work at the Charleston Harbor entrance.

WHERE NOW: Moving back and forth between dredging and disposal offshore.

CAUTION: The Bayport and Newport are hopper dredges that suck material off the bottom, store it onboard and dispose of it on the ocean bottom through a hatch in the hull. Only surface pipes are in the water immediately around these craft.

4. Dredge Alaska

WHAT: Folly Beach renourishment.

WHERE NOW: Expected to move 3-4 miles offshore this weekend or early next week.

CAUTION: Submerged pipelines pumping to shore, but lines surface along the dredge and near shore. Dredge accompanied by support craft including a warning vessel.

ONLINE: To locate dredges real time: marinetraffic.com/ais/.

Source: U.S. Army Corps of Engineers