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How do inclined planes and vertical lifts move boats between water levels?

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View of Utrecht's Oude Gracht canal lined with historic brick buildings, arched doorways at water level, and boats moored along the canal edge in the Netherlands. — canals and inland waterways The *Oudegracht* (Old Canal), Utrecht, Netherlands.

To move boats between different water levels, engineers utilize inclined planes and vertical lifts as efficient alternatives to traditional locks.

Inclined Planes

Inclined planes transport vessels along a slope between adjacent water levels. Historically, boats were hauled on trolleys or trucks using animal power, gravity, or steam. In modern systems, vessels are often carried in large water-filled tanks called caissons. Depending on the site's geography, boats may be moved longitudinally up a gentle incline or transversely if the gradient is steep. Mechanisms such as drum-and-cable systems are used to haul these vessels up the slope, while gravity assists the descent.12

Vertical Lifts

Vertical lifts transport vessels floating within a steel caisson directly between two water levels. These systems replace multiple locks and operate using several mechanical methods:3
* Hydraulic Rams: High-pressure systems lift the caissons vertically.3
* Submersible Floats: Buoyancy-based systems that raise or lower the tank.3
* Counterweights: Systems using weights, ropes, and electrically driven gearing to balance the caisson, allowing for controlled movement.3