PRO 4

Tether Management

Tether management can have a significant affect on the ability to pilot the ROV and achieve the objectives of the mission.

Tether Management includes selecting the appropriate type of tether and managing the deployment and retrieval of it during operations.

Choosing the right tether and managing it can have a very significant impact on the outcome of an ROV dive.

Tether is available in neutral or negative buoyancy. Negative tether sinks but has larger conductors, which means longer lengths can be used without affecting the power available at the ROV. Neutral tether is neutral in fresh water (slightly buoyant in salt water), but has thinner conductors. Neutral tether is available in standard diameter and performance diameter (also called PPT), which is thinner. Thinner tether has less drag, but also has smaller conductors and less power transmission capacity. Selecting the right tether is a balancing act between performance and handling characteristics.

General Tether Use Recommendations

• Make sure tether connections are secure.

• Use the shortest amount of tether required to operate in the target area.

• Use Performance or Neutral tether at the ROV and if more tether is needed use Negative at the control panel.

• If possible, select a deployment site that aids in ROV piloting and tether management. Usually, this means up-current from the zone of operations and with a direct line of sight to avoid snags.

• Only deploy what is needed - too little will affect piloting - too much may result in snags, tangles or propeller cuts.

Tether Storage

Tether should be stored on a TDS or coiled using an over/under or figure eight technique. Coiling the tether in one direction will result in twists that are hard to remove.