Altra HDOCB Solutions


Application Profiles Marine Market

Anchor Handling Vessel Winches

Product: Wichita Kopper Kool Clutch

Kopper Kool water-cooled, hydraulically-actuated clutches were supplied by Wichita Clutch  for use on a large load winch drive system aboard an anchor handling tug supply (AHTS)  vessel. The AHTS is specifically designed for towing and anchoring semi-submersible oil and gas exploration drilling platforms. In deep water exploration fields, drilling platforms are tethered to the seabed more than a mile beneath the surface.

The vessel features a large diameter drum, 600 ton capacity winch and two smaller diameter drums, 500 ton capacity winches which all accommodate heavy-duty cable up to 3 in. diameter. The ship has an open stern allowing for easier cable access and the decking of anchors.

The 43.5 in. diameter KKC 336H clutch models provide enhanced operational safety due to their ability to slip under torque overload during snag conditions. In rough seas, the clutch slips to provide wave compensation while reducing overload/strain on the winch drive system. This slip power handling capacity is achieved by use of continuous water cooling flow beneath the copper alloy wear plates that come into direct contact with the friction material.

The Kopper Kool units offer the additional benefit of increased payout speeds by allowing a slip differential across the clutch while maintaining fine payout tension control. This is especially important when carefully lowering equipment or anchors to the seabed in high wave conditions. The clutch can provide emergency payout by releasing all tension if a problem occurs, such as when a cable gets severely misaligned to the side of the vessel while performing towing operations.

The winch drive system also incorporates six Wichita LKB spring-set brakes, which function as static holding brakes. The brakes are mounted opposite of six motors on 3 gearboxes.


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Wichita Kopper Kool Clutch


Special Features

  • (3) KKC 336H Kopper Kool Clutches with

    112,500 torque rating

  • 1,680 kW continuous slip power handling capacity

  • Copper disc design for high heat dissipation

  • Long-lasting friction material

  • (6) LKBH 217 Spring Set Brakes with 74,460 torque rating


Flight Deck Lifts on Aircraft Carriers

Product:Twiflex VMS 2 Brake Calipers

A major elevator OEM specifies Twiflex VKSD disc brakes for use on high-performance elevator drives installed in skyscrapers.The dual function brakes stop the elevator cars precisely at the correct floor level and also decelerate the cars in an emergency (such as a malfunction). Two caliper modules are used on each elevator drive to provide the required redundant safety.

Unlike electromagnetically actuated brakes found in conventional elevators, the VKSD brakes are hydraulically actuated since each caliper’s clamping force exceeds 100 kN.A dedicated dual-circuit hydraulic unit (also supplied by Twiflex) generates the necessary oil pressure for both brake calipers.

The brake system is designed to dissipate the large amount of kinetic energy (which may exceed 2 kWh) generated bythis high rise elevator application. Brake disc temperature can rise bymore than 100K during an emergency stop.

The Twiflex VKSD disc brake caliper range is available in a standard configuration comprising two spring modules acting on each side of the disc or, as shown above, as a 'floating' brake. The minimum disc thickness is 20mm, minimum disc diameter is 1000mm. Rated braking force extends from 28 kN to 119 kN, with a nominal coefficient of friction mu = 0.4.

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VMS/2 Brake Calipers


Special Features

  • Four VMS/2 Spring Applied, Hydraulically Released brakes
  • Total braking force from calipers greater than the thrust of three 747 jets
  • Motor output of 250kW supporting a static load of up to 27.5 tonnes

Diving Support Vessel

Product: Wichita AquaMaKKs LI-SSB Brake

Wichita Clutch has supplied AquaMaKKs low-inertia, spring-set brakes (LI-SSB) for use on diving support vessel (DSV) mooring winches. The DSV is used for inspection, maintenance and repair of offshore oil and gas pipelines and platforms. A 4-point, computer-controlled mooring system maintains the ships position over a dive site while compensating for swell, tide and prevailing wind.

AquaMaKKs LI-SSB brakes are installed on each of the mooring system’s four deck-mounted, AC motor driven winches. The units serve as stop-and-set parking brakes to hold the vessel in precise position. In the event of power loss, the brakes are calibrated to provide a controlled emergency stop which prevents vessel drift while protecting drivetrain components.

The AquaMaKKs LI-SSB has been specially modified to withstand highly corrosive sea spray and direct seawater splash prevalent in marine deck areas. These LI-SSB models utilize the standard, offshore-proven, AquaMaKKs brake housing which features three-part epoxy marine grade paint and stainless steel hardware for added corrosion protection. Special alloy stainless steel wear (center) plates are also incorporated to resist damage from corrosion. An engineered friction material was specially designed to run against the stainless steel wear plates.

AquaMaKKs LI-SSB air-cooled, air tube release high-torque brakes are available in the 19, 25, and 36 inch sizes. Units feature a shim design that makes it easy to maintain and adjust for wear. Models can be easily converted into water-cooled brakes.


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Wichita Clutch AquaMakks LI-SSB Brake


Special Features

  • Low inertia, air-cooled, spring-set, air tube release, high-torque brakes
  • Specially modified to withstand sea spray and direct seawater splash
  • Provides accurate torque control
  • Three sizes available with up to 750,000 lbs. static torque rating

Shiplift Braking Systems

Product: VMS 2 Brake Calipers

Twiflexis chosen to supply braking systems to multiple shiplifts in the Asia Pacific region because of its superior technology and experience in the industry. A recent application involves the Gaobazhou Hydroelectric Dam shiplift located 12km from the convergence of the Qing Yangtze Rivers.

The total capacity of the Gaobazhou powerstation is 252MW and the yearly output of electricity is 898 million Kw. h. The damis 435.9m wide by 83m tall. The shiplift at Gaobazhou is designed to liftships weighing up to 300 tonnes and is the only means of navigating the powerstation dam.

Ships sail directly into a large water tank. Water gates then seal the tank at each end and a 300kW hoist lifts the tank (with ship inside) 40.3m to the upper level. The gates then open and the ship sails on up river. The whole exercise takes less than 12 minutes; considerably faster than a conventional lock gate arrangement.

Four 75kW motors drive a total of eight hoists. The total lift is 1560t but a counter balance of 1024t brings the out of balance load to just 536t. A total brake torque of 1840kNm is required to arrest the hoist under emergency conditions. The 4 VCSmk-lll working brakes assist in stopping the hoist and the 24 VMS-2 safety brakes come on at full torque in order to “park” the system. The VMS-2 brakes come in on a “step-by-step” method to arrest the hoist in a smooth and efficient manner.

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VMS/2 Brakes


Special Features

  • 24 VMS-2 brakes installed on 1560 tonne shiplift to arrest the hoist in smooth and efficient manner
  • 4VCS mK--III brakes assist in stopping the hoist
  • Superior technology and experience in shiplift industry

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