Water rig
Large-volume controlled water release used for storm sequences, hull breaches, and engineered tidal moments — see Master and Commander, Kon-Tiki.
Mechanism
A dump-tank is a large overhead reservoir (typically thousands of gallons) released through a programmable valve onto the performance area. A water cannon is the same volume routed through a directional nozzle for horizontal impact. Both rigs are calibrated to deliver a specific volume at a specific velocity for a specific duration — the choreography document specifies the dump in cubic-feet-per-second at each beat. Performers wear life vests under costume, take their performance positions on safety-line tethers anchored to the floor outside the dump cone, and the take begins on the safety officer's clearance.
Safety
A dump of significant volume is fundamentally an industrial hazard. Performer separation from the dump-cone center is calculated against worst-case overshoot from the valve. Tethers are inspected before every take. After a dump, the working area is checked for displaced set elements, injured performers, and any dewatering issues that would affect subsequent takes. Cold-water dumps use heated water raised to skin-safe temperature; even a brief exposure to unheated water above 80 lb-volume can produce hypothermia risk.
On screen
Sequences in the archive whose discipline tags overlap this technique's category. Click through for the full rigging breakdown of each set-piece.