Water ballast compartment for buoyant marine devices

In an elongated buoyant marine device intended for use in a generally vertical position and carrying a pyrotechnic candle which during burning will cause a loss of weight and consequent change in center of buoyancy, including

• a ballast compartment situated below the center of gravity of the marker when the marker is in said generally vertical position;
• at least one water inlet port near the lower end of the ballast compartment for entry of water into said ballast compartment;
• at least one air exhaust port near the upper end of the ballast compartment to permit passage of air from said ballast compartment as water enters said ballast compartment, the improvement comprising
• the size of said ports being selected so that water will enter into and air will exhaust said compartment at a controlled rate so that the filling of the ballast compartment by water takes place over substantially the time during which the candle burns, wherein the increase in weight of the device due to water entry into the ballast compartment will approximately offset the decrease in weight due to burning of the candle at any give time during the burning cycle, whereby the device is maintained in said generally vertical position.