The dorade box (also called a dorade vent, or collector box) is a type of vent that permits the passage of air in and out of the cabin of a boat, while keeping rain, spray or sea wash out.
The basic form is a low, rectangular box fixed to the deck or cabin top, fitted with interleaving vertical baffles. The baffles alternate to be free at the floor of the box, or free at the ceiling, forming a series of chambers.
A ventilation cowl is usually fitted to a large hole at the top of the chamber at one end of the box, and another large hole opens down into the boat from the chamber at the other end. Limber holes perforate the wall of the box at the floor of each chamber.
Dorade boxes operate on the principle that air can pass relatively freely through the chambers, yet rain or sea wash will be trapped in successive chambers and drain out the small holes in the sides of the box.
The principle can be applied to other forms. For example, one variant has a circular layout with the baffles as concentric rings.