Powered sheave for node deployment and retrieval

A method for deploying a plurality of seismic sensor units into a water column, comprising:

• providing a cable handling device, coupled to a marine vessel, the cable handling device comprising a powered sheave and an idler sheave, the powered sheave having a first cable contact area and the idler sheave having a second cable contact area opposing the first cable contact area;
• coupling a length of a flexible cable to the cable handling device in a route to contact the first cable contact area and second cable contact area to maintain a frictional force applied to a section of the flexible cable;
• routing the cable from the powered sheave to the stern of the vessel to pass across a workstation;
• deploying a free end of the cable into the water column while increasing the motion of the vessel to a first speed;
• providing a deployment rate of the cable to a second speed by adjusting the rotational speed of the powered sheave to produce a desired fall pattern of the cable in the water column;
• and
• attaching at least one of the plurality of seismic sensor units to one of a plurality of attachment points disposed on the cable as the cable passes the workstation.

A method for deploying a plurality of seismic sensor units into a water column, comprising:

• providing a length of flexible cable from a cable storage device disposed on a vessel to a powered sheave, the cable having a plurality of spaced apart attachment points;
• routing the cable from the powered sheave to pass adjacent a workstation disposed on the vessel;
• attaching an anchor device to a free end of the cable;
• deploying the free end of the cable into the water column while increasing the motion of the vessel to a first speed;
• operating the vessel at the first speed while providing a deployment rate of the cable at a second speed, the second speed being greater than the first speed;
• decreasing the second speed of the cable as an attachment point approaches the work station;
• and
• attaching at least one of the plurality of seismic sensor units to the attachment point at the workstation, wherein the deployment rate is varied to provide a desired fall pattern of the cable in the water column.