Iivari's quick bridge

History

Iivari's quick bridge was first put forward by Kauranen in a 1933 issue of Suomen Sotilasaikakausilehti. It was meant to take over from earlier French and German models, which each had their own shortcomings, and it borrowed some features from the French version. A major benefit was that it could be built from various types of wood, often gathered right where it was needed, and its joints could be secured with anything from rope and nails to tree roots. Since the bridge gets its buoyancy from supports placed across the current, it does not work well in fast-moving water. For that reason, it was used together with the log quick bridge designed by Eero-Eetu Saarinen and other types. The bridge is only practical in water moving slower than one meter per second and no wider than fifty meters. Because it was simple to teach to ordinary infantry and the required materials were easy to find in Finland, it made crossing rivers much simpler and freed up engineers to handle larger water obstacles. During the Winter War, it made possible the standard tactic of having the assault force cross on this bridge while truck-borne support units used boat pontoon bridges, known as ruuhisilta. After the war, the bridge stayed in use: infantry trained with it into the 1980s, and coastal troops continued until the 1990s, when a six-month training cycle forced a shift to more basic skills. As of 2019, engineer units still occasionally build Iivari's quick bridge, and instructions for it appear in the 2024 survival manual of the Finnish Defence Forces.