November 15, 2019 | Univ. Delaware

During the summer, 2019 researchers from University of Delaware placed an oceanographic measuring device approximately 20 miles south of LUMCON. The equipment worth around $150,000 weighed nearly 200 pounds and was roughly rectangular 5′ X 3′ X 3′, and attached to a surface float by a 1/2″ line. At some point another vessel ran over the float detaching it from the line and device, making it impossible to relocate and lift without divers.

In November, personnel from University of Delaware arrived with a towable magnetometer and departed aboard R/V Acadiana with a scientific dive team. For about two hours bottom surveys were conducted for the device which lay in about 60fsw in the open ocean. Finally a blip was seen which was suspected to be the sensor package and marked on GPS. For another hour lames were run over the spot from various directions in a wagon wheel pattern and each time the blip was spotted it was marked on the GPS map. Eventually confidence was high that the device was within a 100 square foot spot and a marker buoy was placed.

Divers descended to the bottom to near zero visibility conditions, in pitch blackness. Per pre-dive planning a wreck reel was taken to conduct circle searches in a 100′ diameter with one diver in the middle and one diver swimming. The first circle yielded no results and the divers surfaced after a safety stop to reassess and sit out a 45 minute surface interval before returning to the water.

On the second attempt the swimming diver completed about 3/4 of the planned 100′ diameter swim. Then in the inky gloom a line appeared on the bottom. The line was followed back for several hundred feet through the murk and found to be the buoy line still attached to the device. A strobe light was attached and a surface marker sent up. The diver next followed the wreck reel line back and retrieved the center of the search pattern diver, both returning to the surface after another safety stop.

At this point the decision was made to use the existing buoy line to lift the device. R/V Acadiana moved in and retrieved the surface float with a boat hook. The line was threaded through the crane guide and the equipment safely brought aboard and gently placed on the deck. It was later determined that the device was nearly a half mile from its original position and most likely had been dragged by a shrimp net or fishing traweler.

Leave a comment