Long time SeaBotix client Orca Maritime specializes in underwater security, survey, GIS, marine services and training. As a known expert in the local San Diego area Orca Maritime was contracted to recover a lost Experimental AUV. Armed with a new vLBV300 ROV system and an approximate last known location the team set out on the recovery mission.
Departure time was 06:15 with an estimated transit time of just under three hours. Operating from an eleven meter RHIB and a crew of four the sea state was cooperating. The journey was smooth and uneventful with the search location offshore from San Clemente reached at 09:00. Once onsite the RHIB was able to easily hold position as the wind was mild and the sea state so flat.
Preparation for the recovery mission involved dropping a clump weight and line to the approximate known location of the AUV. Unfortunately during deployment of the clump weight the line broke and the clump was lost to the sea floor. A second clump was organized and deployed successfully. Always good to have backup. To aid in locating the clump and line during descent and operations a series of chem-lights were fitted. With the clump and line deployed the vLBV300 system was setup and pre dive tested. All tests checked out. Not knowing the conditions of the AUV and what caused the system to not return prompted the team to configure the vLBV with both a grabber and a cutter. Having the dual function enable the vLBV to cutting any entanglements as well as grab the AUV.
vLBVChad Nelson of Orca Maritime was the vLBV300 operator. With all systems go the vLBV300 was deployed and descent to the sea floor was commenced. Depth estimates were around the 200 meter (660ft) mark. To keep track of position Chad followed the weighted line to the sea floor, which was reached approximately seventeen minutes after deployment. In addition to the weighted line the vLBV300 was fitted with the Tritech Micron Nav USBL acoustic tracking system. Once on the bottom Chad rotated the vLBV300 360 degrees for a quick search of the target. Remarkably the target was instantly spotted.
The AUV had a wire guided system and during the mission planning it was determined that the wire should be cut near the base of the feed tube at the rear of the AUV. Chad piloted the vLBV300 to the AUV and in short order managed to cut the wire. After cutting the wire Chad grasped the AUV tail cone with the three jaw grabber. Using the dual vertical thrusters the vLBV300 ascended to the surface with the Remus in hand. Once on the surface the team recovered the AUV to the RHIB. From time entering the water to recovery into the RHIB was just 50 minutes.
With the asset recovered the team returned to shore with a very happy client.
[mappress] Subsea World News Staff , March 23, 2012; Image: SeaBotix