Strainer

A strainer is an object below the surface of a river, usually a tree or branch which allows water to flow, but tends to stop large objects. These river features provide no entertainment value for the whitewater paddler. They are simply dangerous. They can entangle or trap a swimmer in current causing them the unfortunate consequence of drowning.

Strain"er (?), n.

1.

One who strains.

2.

That through which any liquid is passed for purification or to separate it from solid matter; anything, as a screen or a cloth, used to strain a liquid; a device of the character of a sieve or of a filter; specifically, an openwork or perforated screen, as for the end of the suctionpipe of a pump, to prevent large solid bodies from entering with a liquid.

© Webster 1913.