Thern recently provided winches to a fish lift in Menominee, MI where every Spring, the DNR attempts to move spawning sturgeon from the downstream side of the dam — Lake Michigan and the tail end of the Menominee River — to the upstream side of the dam (Menominee River) using a fish lift. The three winch/hoist operations in this system consist of a Thern 4HPF winch, a Kone Crane and a set of Thern hand winches.The 4HPF winch is used to lift a screen that controls the passage of fish into the lifting hopper. The screen is raised for a 15-minute period to let fish into the lifting basket/hopper. VFD controls are used to avoid a hard fall when lowering and stopping the screen — the desired soft stop.
The second winch used is a Kone 10-part line hoist that lifts the hopper. The fish swim into the hopper once the screen is raised and continue to enter until the screen is lowered. The hopper is then raised 20 or so feet to an elevation where the fish are dumped into a holding tank where they are inventoried and sorted. The sturgeon end up in other holding tanks to await transport by truck to the upstream part of the river, and the remaining fish are released back into the lower reaches of the river and Lake Michigan (down a tube you can kind of make out on the right side of the dam photo).
The third set of winches are Thern’s stainless steel hand winches which are used to raise debris screens on the upstream side of the water flow. These screens are raised infrequently as there are already trash racks on the upstream side of the dam at the main inlets.