Cable Services – Simulation

Makai’s technical staff have deep theoretical and practical knowledge of cable installation and retrieval, towed arrays, drag arrays, tow fish and anchor deployments. Using the advanced simulation features in MakaiPlan Pro, Makai has run customized simulations to answer specific questions about installations of seismic arrays, power cable lays, communication cable deployments, branching unit installations, cable repair operations and towing of arrays by surface and underwater vehicles.

Installation Feasibility Studies

Makai can perform accurate simulations to determine the feasibility of the given cable installation, taking into account ship and other equipment limitations as well as the expected environmental conditions. Simulations can be run to include typical at-sea instrument and operator errors. Instruments errors such as GPS position errors, cable length measurement errors and errors in the knowledge of the ocean currents and bathymetry can be easily incorporated in the simulations. Operators errors such as how well the DP and cable engine operators can follow the instructions can also be incorporated in the simulation. Using the results, we can perform an error budget analysis and determine the factors that are limiting the operation.

These computer simulation realistically reproduce actual at-sea lay conditions and allow the planner to estimate the probability of success to achieve the desired cable touchdown positions and the cable slack (or tension) at the seabed. Any potential installation problems can be found during these simulations, and corrected before they become costly mistakes during the actual at-sea installation.

Equipment Selection

Makai can perform simulations to quantify the effect of each instrument on the cable lay accuracy. Makai can simulate DP systems, GPS, Cable engines, Acoustic Doppler Current Profiler (ADCP) to measure ocean currents in real-time and the use of transponders attached to the cable. We can objectively answer questions like:

  • Will a more expensive  ADCP with longer range meaningfully improve my installation accuracy?
  • Do I need to use transponders attached to the cable to meet the required installation accuracy?
  • How does the installation speed affect my placement accuracy?

Answering these questions allows us to present the client with a trade-off analysis of equipment costs vs. accuracy achieved and risk minimization. In addition, we may help clients with deck layout, peripheral equipment selection, and operational procedures when requested.

Installation Planning

Makai can create a preliminary and detailed installation plans (or Ship Plans). The ship plan provides detailed information on:

  • Ship trajectory (waypoints)
  • Ship speed, and
  • Cable engine payout rates during the lay (to install the cable on the seabed at the location and slack/tension conditions required by the Route Positioning List (RPL)).

The ship plan will include all the vessel speed control for each cable type being deployed as well as speed changes required to prevent cable suspensions on the seabed, changes in cable payout rate in order to properly achieve the required seabed slack at all times during the lay, maximum turns the ship can comfortably perform, etc.  The ship plan will also take into account the cable dynamics, such as those that occur during cable type changes, ship speed changes, deployment of repeaters or ship alter-courses. The end result is a final Ship Plan: a detailed set of ship and cable payout instructions to be used for a successful cable lay.