Colliers Engineering & Design designed a new dedicated hoist system at the powerhouse tailrace to replace an out-of-service Whirley Crane.

This 52.2 MW hydropower facility has three vertical turbine-generator units and is located on a lake in the southeastern United States. There are two existing draft tubes for which gates are used to dewater any one of the three turbines. In the past, a Whirley crane was used to install gates when unit dewatering was required. The Whirley crane is red-tagged Out of Service.

The goal of the project was to design a new dedicated hoist system at the powerhouse tailrace that can install the gates for any one of the three units. After the investigation, however, the owner decided to proceed with a new gantry crane and fixed hoist to run on a new rail system. The new hoist was designed to have enough capacity to lift one gate at a time, along with a lifting beam, while maintaining an adequate safety factor. The lifting beam also included an automatic latching system so that one hoist can install both gates at the bottom of the gate slot.