Tunnel (barge)

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The tunnel on inland waterway vessels is formed by pairs of side skirts directly in front of the propellers . When the water level is low and the ship is partially laden, it prevents air from being drawn in. When the ship is deep in the water, it worsens the efficiency.

An improved flow to the propeller can be achieved with a flex tunnel , in which the aprons are designed as movable flaps that can be folded in and out of the water with hydraulic cylinders when the ship is deep in the water.

Tunnels were introduced because the draft of inland vessels is limited, but ever larger propellers were used, on the one hand because modern ships are larger and on the other hand larger, slower-turning propellers are more efficient.

literature

• Krischan Förster: More flexibility with a flex tunnel . (PDF; 1.2 MB) In: Binnenschifffahrt , No. 9, 2013; via Flextunnel with a picture of a conventional tunnel