To this end a flight of locks was considered, but disregarded due to sitting problems as well as loss of water from the canal, which had to be considered. A boat lift being proposed as a workable solution in 1870.
Edward Leader Williams was given position of chief engineer and drew up plans for a design using a pair of water-filled caissons. These counterbalanced one another, so reducing the amount of power required to transport the boats. Water filled hydraulic rams were used to do the work and were designed by Edwin Clark who accepted position of principal designer.
The two caissons were made of wrought iron to dimensions of 75 ft (22.9 m) long by 15 feet 6 inches (4.7 m) wide by 9 feet 6 inches (2.9 m) deep, allowing the passage of two Narrowboats up to72 feet in length in each caisson, or a single wider barge.
Power was provided by a 10 horsepower steam engine.
In 1904 under the supervision of Colonel J.A. Saner the mechanism was redesigned replacing the hydraulic rams with an arrangement of counterweights electric motor and pulleys. This required a redesign of the general superstructure that had to be considerably strengthened. A 30 hp electric motor was installed, with only half this power being used in normal operations. work was completed in 1908.
This design worked successfully for the next 75 years, with the added benefits of easier and less expensive maintenance, until closure in 1983
