Dry dock flooding, 1965
![Two flooded structures](https://www.communitystories.ca/v2/pont-tunnel-louis-hippolyte-lafontaine_bridge/wp-content/uploads/sites/130/2020/01/PrtScr-capture_20.jpg)
Société d’histoire des Îles-Percées
Once underwater, the rubber collar on the right extremity of the caisson was pressed up against the metal plates of the next caisson. Under the 55,000-kilopascal hydrostatic pressure of the river, the rubber contracted to form a temporary watertight seal.