Deep Well 18K Powered Capstan


The main benefits provided by this device are:

  • Reduces spooling tension to help alleviate cable crush
  • Reduces drum loading to help prevent drum failures
  • Can be operated going into and out of the well to maintain wireline spooling profile
  • Torque unit replaces top sheave and reduces load on rig up equipment
  • Provides additional line pull to assist hoist unit
Zone Power - Powered Capstan

The Powered Capstan is a traction winch that provides additional lifting force on the cable. It works in sync with the main winch to augment lifting capacity, stabilize cable tension and reduce cable crush.

Also known as a Power Sheave, Capstan Winch or Traction Winch.


The ZP Powered Capstan is a traction winch that is used in conjunction with a wireline winch/hoist unit to assist in its operation with high-tension wells and/or deviated wells while down hole logging. It is capable of assisting the wireline winch unit, reducing the tension on the wireline winch by up to 18,000 lbs. But importantly it can also increase the tension on the winch drum while there is low wireline tension. Therefore it can keep constant tension on the winch drum (within certain limits) with varying wireline tension. It can nearly be thought of as an offshore winding shop.

It comprises of three main components, the Capstan Winch, Hydraulic Power Pack and the Electronic Control Panel. The torque unit can be located in a hazardous area as it has no electrical parts, the power pack is designed to operate in UL Class 1 Division 2 or ATEX Zone 2 areas and the electronic control panel has to be located in a safe area (usually the winch/hoist unit). The hydraulic power pack is DNV 2-7.1 for lifting and there is a separate DNV 2-7.1 transport frame for the capstan winch and a DNV 2-7.1 transport basket for the hydraulic hoses.

The torque unit can be either hung in the derrick from the blocks or on the deck to make it operationally versatile. Originally the ZP Power capstans were designed for deep wells. When logging either deviated and/or deep wells the wireline cable tension can be high. The ZP Power Capstan can assist the winch, taking some of the strain, typically reducing the tension on the winch by up to 9,000 lbs or 18,000 lbs depending on the model of Capstan. But this is not the main benefit.

When logging deviated wells the wireline cable tension can be very low when running into the well. When the wireline is spooled back on the drum it will be at a relatively high tension. Ideally wireline cable should be spooled back onto the drum within a 5:1 tension ratio i.e. if the cable spools off at 1,000 lbs tension it should not be spooled back on above 5,000 lbs tension. This keeps a similar torque on the cable armour and avoids the armour bird caging and then the conductors crushing on subsequent operations. The ZP Capstan can keep the same constant tension on the winch drum going both into the well and when coming back out there by extending wireline life.

Product Details - 18K Powered Capstan

Capstan Winch – 18K Pounds

Wire line cable is carried around twin 31" diameter torque wheels by steel segments machined to give 180° of support to the cable diameter.

The grooves are machined to suit selected cable. Freewheel speed exceeds the normal winch operating range. The control system achieves an extremely smooth application of rim pull to the running or static cable. The winch is supplied in a Transit Frame, easily removed from the side or from the top, complete with lifting slings.

The winch can be mounted horizontally to the deck or vertically in the derrick.

The winch is hydraulic powered and is ATEX and DNV 2.7-1 compliant.

Hydraulic Power Pack

The power pack has a 100HP (75kW) electric motor as the prime mover that is coupled to a variable displacement hydraulic pump.

There is an explosion proof 100HP motor starter, that also houses other control equipment (such as intrinsically safe barriers for hydraulic oil pressures, level and temperature sensors).

The power pack is connected to the electronic control panel a single 24 core umbilical cable. All signals in the umbilical cables are 24VDC.


Electronic Control Panel

The electronic control panel controls the hydraulic power pack and torque unit. It is to be operated in a safe area and can be installed inside the logging unit or in a remote location such as a work shop. If it is installed remotely then a small control panel is installed
inside the logging unit so the system can be fully controlled by the logging crew.