8 Janurary, 2006
Winches were a very "high maintenance" item on the Kawishiwi. They were constantly exposed to salt spray and required regular PMS to keep them working properly. The salt spray was especially corrosive to the steam lines that supplied power to each winch. Even though these lines were "lagged" with insulation to prevent burns and loss of heat from the steam, salt water would find it's way inside the lagging and the lines would soon be full of pin holes. I think that we replaced every foot of steam line on the main deck in a 3 year span.
Another problem with the steam winches was that the rig operators controlled the winches via cable operated remote control levers from as much as 75 feet away from the winch. Each remote control lever required a number of pulleys and cable guides that all caused friction and made the levers hard to operate. This was a very physically demanding job (winch operator). During unreps, the winch operators needed iron biceps and total concentration to keep the required tension on the cables and keep the hose saddles properly positioned as the Kawishiwi and the receiving ship surged back and forth causing the distance between the two to increase and decrease. This was particularly true for the rigs that did not benefit from ram tension devices. As I recall, virtually all of the winch operators were burly six-footers. Little guys need not apply!
After I got out of the Navy and started to sail with MSC, they sent me to the Navy "Winch Hydraulics & Electronics" "C" school at Treasure Island, Calif. By this time a subsequent class of navy oilers, ammo ships, stores ships and multi product ships had been introduced, and they all relied on electric motor driven hydraulic winches which had been introduced into the fleet to lessen some of the problems mentioned above with the physical requirements of controlling the winches which now operated with electronic "joy sticks" similar to a video game. The Navy continued to experiment with multi generations of hydraulic winch, trying to find the ultimate level of control. These problems were especially vexing on the cargo transferring ships that needed for the "inhaul" and "outhaul" winches to work in harmony to maintain a taught transfer wire while simultaneously moving a loaded hook from one ship to another. A complex proposition.
Unfortunately, this increased level of sophistication led to great problems in maintenance and reliability.
All this high tech electronic & hydraulic gear was very difficult to maintain in the harsh salt water environment on the weather deck of an oiler or supply ship. The myriad of electronic components and electrical connectors were troublesome. The sophisticated hydraulic system was somewhat sensitive to temperature and extremely sensitive to dirt and contamination. One of the regular jobs of the deck engineers on these ships was to flush and "polish" the hydraulic oil reservoirs of these winches with a portable pump and filter unit that could be moved from one winch to another. When starting in cold weather, the winches had be be run for hours to warm up the oil before unreps or the winches became unpredictable and could "run away". The Navy spent millions upon millions on these winches and the maintenance, training and repair they required.
Then some guy got a brilliant and simple idea. A new class of winch emerged with pneumatically controlled winch drums. Gone were the complex hydraulic and electronic systems. Each new double-drum winch used a pneumatically controlled slip-clutch for each drum. The electric motor powering the winch runs all the time. The speed and tension of each drum is controlled by the air pressure to the pneumatically controlled clutch. Increase the air pressure and the speed / tension of that drum increases. Decrease the air pressure and the speed / tension decreases. So this became sort of like holding your car stationary on a San Francisco hill by slipping the clutch. You would not want to do this for long in a car, but these winch clutches were designed to slip continuously with little wear and no damage. Once the transfer wire was passed to the other ship, both inhaul and outhaul winch drum clutches were raised to the same pneumatic pressure to tension the wire. As the ships moved in and out the winch clutches would slip to allow the cables to extend or retract (keeping a constant tension with no operator intervention or skill required). To move the hook towards the receiving ship the pressure on the outhaul clutch was increased. To move the hook back to the supply ship the pressure on the inhaul clutch was increased. No electronics, no precision parts, a very simple control system and a saltwater friendly system overall. Amazing that someone didn't think of this earlier!
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