Typical metal sluice vent grate. In the 1800's a rotund canal Supervisor fell through the wooden grate 13 ft into the rock sluiceway to be spit out into the lock pit amazingly mostly alive. He mandated steel grates which are still there today, 180 years later.

Typical metal sluice vent grate. In the 1800's a rotund canal Supervisor fell through the wooden grate 13 ft into the rock sluiceway to be spit out into the lock pit amazingly mostly alive. He mandated steel grates which are still there today, 180 years later.