The Mark IV high-availability subsea BOP control system – featuring an industry-first three-POD design – improves operational availability of the drilling system through redundancy and improves reliability through simplified POD design. Conventional subsea BOP control systems use a two-POD design, providing a single spare if the primary control POD becomes unavailable. The Mark IV-HA control system  system’s third POD provides additional redundancy, which eliminates the need to pull the stack if one POD fails. It can also improve the subsea control system’s availability to as much as 98%, and reduce the likelihood of a POD-related stack pull by up to 73%.

The Mark IV-HA control system simplified design increased reliability and functionality in a smaller footprint. Designed with 50% fewer tubing connections, the potential for leak paths is reduced, and the addition of redundant solenoid pilot regulators means they are no longer a single point of failure within the POD.

Each POD has 33% more available functions to accommodate eight-cavity stacks. The new POD is also designed with pressure-compensated pilot accumulators that adjust automatically for water depth. This feature prevents the chance of human failure and reduces maintenance costs.

The Mark IV-HA control system is 26% smaller than its predecessor, and weighs one-third less than competitors’ control PODs.


  • Three-POD option, each with 160 functions to accommodate eight-cavity stacks
  • Reduction of 50% in internal tubing to reduce leak paths
  • Sub-plate-mounted valves for improved reliability
  • Tungsten carbide seals on small valves for improved reliability
  • Pressure-compensated regulator pilot accumulators that automatically adjust
  • Dimensions: 46 in × 49 in × 14.5 in
  • Weight: 23,000 lbm
  • Compliance with API 16D/53, DNV Drill, and ABS CDS requirements