|A Shift in Thought|
Twin Disc uses firefighting and farming technology in its newest series of marine transmissions.
By Capt. Patrick Sciacca — January 2003
Ten years ago Twin Disc was called upon to modify the transmission on Crash/Fire/Rescue Vehicles. The problem? Their engines would get bogged down dispersing the fire-fighting agent. The goal? Make a transmission that lets the engine run at whatever speed necessary to maneuver around the fire and still have enough power to disperse the firefighting agent. The answer? The QuickShift transmission, a technology with origins in farming machinery.
This transmission is a smart, shock-absorbing system. When it is shifted into forward or reverse, energy is transmitted and controlled by the transmission and, depending on the power requirements at any instant, is redistributed through the driveline at low torque in the safest and most efficient manner. And with the help of some newly designed, hydraulically operated, multidisc clutch packs and solenoids, the system adapts quite well for use in the marine environment, according to Dave Johnson, manager of marketing and communications for Twin Disc. Although the clutch technology has a patent pending and details about it are being held close to the vest, Jim Kearney, vice president of marketing and sales for Twin Disc, did tell me a little about the solenoids.
The QuickShift transmission uses proportional solenoids that allow for a trolling mode without the need for a trolling valve. "It simplifies the system," says Kearney, adding that a traditional trolling valve setup requires numerous shims and adjustments. "Once it [the QuickShift] leaves [the factory] it needs no further adjustment," Kearney adds.
And wouldn't it be nice to shift your boat's diesels into gear without lurching and leaving guests grabbing for a handrail? How about being able to exit your boat's slip without rocketing out like a spaceship breaking gravity? Or maybe improve close-quarter handling? "Until now, large diesel-powered boats could not effectively maintain vessel control below 5 knots. Reducing engine rpm that low would likely stall the engine," says Klaus Meyersieck, Twin Disc product manager for marine transmissions. "The QuickShift's unique ability to regulate engine torque at extremely low speeds allows boat operators to slow prop speed down to 50 rpm or less. This affords controllable maneuvering at slower speeds than even conventional trolling-type transmissions."
This article originally appeared in the January 2003 issue of Power & Motoryacht magazine.