At night, the Coast Guard station is lit up with flashing red and green lights as if decorated for the holidays. Actually, the flashing lights are atop buoys that the Coast Guard crew removed from the river. The Aids to Navigation Team is in the process of swapping the buoys with ones streamlined for winter ice. The summertime buoys are each fitted with a colored light and a solar panel which would be wrecked by ice when the river freezes in the winter. The wintertime buoys, often unlit, do not have any extraneous hardware that can be torn off by ice floes. The buoys are color coded. Red buoys are stationed to the right of the navigation channel (from the point of view of a ship returning from sea), green buoys on the left. The wintertime buoys also have coded shapes, called cans and nuns. A can is a simple cylinder, like an oil drum. A nun is conical, reminiscent of the habits worn by some orders of nuns. Cans are green and appear on the left when returning from sea, nuns are red and on the right. Sailors use a simple mnemonic: “Red right returning.” Red and green lights remind land-lubbers of Santa Claus and mistletoe, but seafarers are thinking starboard and port.