For six straight hours for four straight afternoons during one of the largest ship-hosting events in Baltimore history, all water traffic within a large rectangle in the middle of the harbor is being completely restricted by a cadre of law enforcement agencies.
No tall ships, no personal watercraft, no dinghys. Period.
Only the icebreaker A.V. Sandusky of the Maryland Natural Resources Police and the Coast Guard cutter James Rankin are allowed in the so-called box, and even they are not allowed to move.
The Navy's famous Blue Angels are in town, practicing from 11 a.m. to 5 p.m. Thursday and Friday before performing scheduled aerobatic shows above the harbor Saturday and Sunday, when pilots will maneuver their jets at hundreds of miles per hour and within inches of one another.
The boating restrictions have nothing to do with the safety of those on the water if there's a mishap, but everything to do with the pilots' maintaining control above what is known as their "show line," according to officials briefed on their operations and the Blue Angels' manual for performances.
"They do not want anything in that waterway, I believe mostly for their air navigation," said Maj. Jerry Kirkwood of the Natural Resources Police, which is helping to "clear the box" each day. "They can't have something that takes their peripheral vision."
Blue Angels pilots will be using the Sandusky and the Rankin as points of reference during their flyovers, Kirkwood said, and it could be disorienting if other vessels kept zig-zagging across their path.
"It's obviously very precise," he said of the Blue Angels show — so much so that Natural Resources officers were once asked to turn off a blinking blue light that was distracting a pilot from a boat two miles away during a performance.
"The pilot actually radioed in and said, 'Can you get that blue light turned down?' " Kirkwood said.
The need for what is known as a "sterile" flight path is so critical that the Federal Aviation Administration sets strict guidelines for the amount of space that needs to be clear before an aerial show.
None of the pilots flying this week was available for comment Thursday, busy as they were preparing for their shows this weekend, Navy officials said.
Those preparations are intense, especially for shows over water as in Baltimore, which are "the most difficult air shows to organize and fly," according to the Blue Angels' air show manual.
The optimal show line — or "an absolute straight path over the ground that the demonstration pilots will use as the primary reference for performing their maneuvers" — is a runway, the manual says, with a precisely placed white trailer at the center for reference.
But the "visibility, accuracy, and stability of the show line remain an absolute requirement" over water as well, meaning an artificial show line must be created and checked before any test runs can begin.
The Rankin will be precisely positioned at the center point, in lieu of the white trailer. Then there is the task of clearing out any boaters unaware they're entering forbidden territory.
"For safety reasons," the Blue Angels manual states, "the demonstration will be canceled if water show lines are not clear of unauthorized boating traffic and spectators 30 minutes prior to scheduled takeoff."