Screw clamps. Screw clamps are types which use a screw mechanism to adjust the jaws and clamp a workpiece in place. The types which are found in the screw clamp category include G clamps (also known as C clamps), F clamps, edging clamps, wooden hand screw clamps and rack clamps.
Dry drowning usually happens soon after exiting the water, but with secondary drowning, there can be a delay of up to 24 hours before the person shows signs of distress. Both can cause trouble breathing and, in worst-case scenarios, death.
The symptoms of dry drowning usually begin within an hour of water exposure. Secondary drowning takes a little longer to set in (1 to 24 hours). In this case, a small amount of pool water enters the lungs, disrupting a substance (surfactant) that coats the inside surface of the tiny airways deep inside the lungs. This substance prevents the airways from collapsing and sticking together.