(SEATTLE) — Crowley Maritime has chosen two Markey model DEPC-48 hawser winches to outfit the first all-electric-powered ship-assist tug in the United States.
Informed of Crowley’s selection, Markey President Blaine Dempke expressed pride at joining the team building this groundbreaking vessel.
“Crowley’s eWolf heralds the era of zero-emissions assist tugs for the maritime industry,” Dempke said. “As a one-of-a-kind vessel, stakeholders will be closely following how effectively the eWolf operates on battery power before deciding to embrace this new technology. Crowley Maritime’s choice of our model DEPC-48 speaks to the confidence they have in the operational reliability of Markey’s brand of machinery.”
When landed aboard the 70-foot eWolf during shipbuilding, the model DEPC-48 will tip the scales at 20,500 pounds. The fabricated steel winch drum spans 31 inches and has a 20-inch diameter core, with flanges that measure 58 inches in diameter. These machines spool 500 feet of 9-inch high strength synthetic line. A pneumatically actuated band-type drum brake will hold tensioned lines, and a 50-horsepower AC-variable frequency drive is geared to produce line speeds to 88 meters per minute.
The DEPC-48 is fitted with several options for controlling the winches independently underway or joining both for in-port mooring. Engaging render/recover and tuning the tension set point enables sensor input to monitor line load and continually adjust scope while the master choreographs eWolf’s movements. Actuating the free wheel mode push button disengages the drive, allowing the tug to change station unencumbered with hawser tension. Wheelhouse joysticks permit manual control of drum direction and line speed or manual feathering of the drum brake.
Recharging eWolf’s batteries overnight and on long weekends follows ship-assist operations. Marrying the two hawser winches to form a system saw Markey engineers draw on experience developing the system controls for a two-winch barge set. These automatic mooring system controls hold barges on station within 0.5 feet as Willamette River water levels rise and fall and strong currents act within the Port of Portland. Outfitting automatic mooring controls to these hawser winches frees the tug’s crew to focus on more important tasks when in the Port of San Diego.