When Lowcountry tides rose to 9.9 feet on the new moon last week, the water was lapping at a tidbit of history that helped end slavery.
In the Battle of Port Royal, which took place here 150 years ago next Monday, 200 years of antebellum life ended in less than five hours.
But if the invading Yankees had not understood the simplest of Lowcountry ways, it would never have happened. They knew that war and peace, feast and famine, all fall prey to the tide table.
The battle that gave the Union control of Southeastern ports was planned around a tide much higher than last week's.
The armada of 49 vessels was scheduled to arrive at Port Royal Sound in time for the proxigean spring tide of Nov. 2, 1861. This happens when the moon makes its closest approach to earth, coinciding with the near alignment of the sun, earth and moon. It produces tides 40 percent higher -- and lower -- than normal spring tides. At most, it happens once every year and a half.
Bad weather kept the armada at bay for a couple of days, delaying the capture of Hilton Head Island and Beaufort. But the Union navy still enjoyed higher than normal tides in getting over the bar and into the Sound for the battle of Nov. 7.
The river rat from Massachusetts who made it happen was a civilian assistant in the United States Coast Survey, a forerunner to today's NOAA.
Charles O. Boutelle isn't in many history books, but he was the most important person here. He first had to lead a sounding expedition into the Sound because the rebels had destroyed all navigational aids. He found the channel, buoyed it, piloted the deep-draft vessels into the Sound, and then recorded a vivid description of the battle.
Boutelle had spent five months in the Lowcountry in 1849, charting the waters around Charleston, where he was treated with great respect. He lived in Beaufort for several years during the buildup to the war.
"With the advent of war, his knowledge of the waters and topography of the Southeast coast were invaluable to the Union, but his old Southern friends felt him to be a traitor," says a history of the U.S. Coast Survey. "If he had been captured, he would have been hung as a spy."
Boutelle continued to chart and mark the Atlantic coastline throughout the war. He commanded a 160-foot steamer. His input was sought on every maneuver and by every military commander and ship captain.
And sometimes his charting took advantage of the brawn and expertise of the formerly enslaved African Americans who felt instantly freed by the "Big Gun Shoot" that Boutelle engineered. At day's end, these tireless black oarsmen rowing back to the mother ship would break into song. Their rich voices were applauded as they passed through an anchored Union fleet, the sun melting into the waters of another Lowcountry tide.
Follow columnist David Lauderdale at twitter.com/ThatsLauderdale.