NOAA mobile integrated survey team prepares for hurricane season

NOAA’s Office of Coast Survey is the federal leader in emergency hydrographic response. Consecutive strong storms during the 2017 hurricane season made response efforts challenging, and emphasized the importance of having a well-trained and versatile staff. Coast Survey’s regional navigation managers, navigation response teams (NRTs), and mobile integrated survey team (MIST) worked with partners before and after the storms to quickly and safely reopen ports and waterways.

The MIST equipment is a mobile, quick-install side scan and single beam sonar kit that can be quickly set up on a vessel of opportunity. Recently, Coast Survey sent the MIST team to Astoria, Oregon to conduct a hydrographic survey of the Mott Basin area, which the U.S. Coast Guard (USCG) requested to confirm charted depth and obstruction data.

The MIST group used this as an opportunity to give NRTs experience with setup, usage, and tear down of MIST equipment, as well as to perform a system test prior to the upcoming hurricane season.

Data collection in the Mott Basin aboard the USCG Trailerable Aids to Navigation Boat (TANB) vessel
Data collection in the Mott Basin aboard the USCG Trailerable Aids to Navigation Boat (TANB) vessel

The team installed and integrated the MIST equipment on a USCG Trailerable Aids to Navigation Boat (TANB) vessel. TANB vessels are normally used for navigation aid maintenance, but can serve as a vessel of opportunity for hydrographic surveys using MIST equipment. During the 2017 hurricane season, NOAA used USCG vessels of opportunity in Florida and Puerto Rico for rapid hydrographic survey response.

Setting up the MIST equipment on a USCG TANB vessel
Setting up the MIST equipment on a USCG TANB vessel

The deployment to Mott Basin in not only provided USCG with hydrographic data to meet their operational mission, but also allowed NOAA to exercise equipment that will be critical to any upcoming storm or emergency response.

The MIST and USCG survey crew. Tim Wilkinson (NRT3, far left),Erin Diurba (NRT4, second from left), Alex Ligon (NRT1, second from right) and Mike Annis (HQ, far right) represented Coast Survey.
The MIST and USCG survey crew. Tim Wilkinson (NRT3, far left), Erin Diurba (NRT4, second from left), Alex Ligon (NRT1, second from right) and Mike Annis (HQ, far right) represented Coast Survey.

Coast Survey’s NRTs conduct hydrographic surveys to update NOAA’s suite of nautical charts. The teams are strategically located around the country and remain on call to respond to emergencies speeding the resumption of shipping after storms, and protecting life and property from underwater dangers to navigation.

Coast Survey uses unmanned technology to find submerged danger to navigation

Coast Survey has been discovering and marking the locations of underwater dangers since our surveyors took the nation’s first official ocean soundings in 1834. We’ve used or developed all the technological advancements – lead lines, drag lines, single beam echo sounders, towed side scan sonars, and post-1990 multibeam echo sounders – and now we can point to a new major advancement for fast deployment and quick recovery. In February, Coast Survey’s Mobile Integrated Survey Team (MIST) used an autonomous underwater vehicle (AUV) to locate a submerged buoy that was interfering with anchorages in the Chesapeake Bay.

“You and the crew of the HASSLER put us right where we needed to be!” said a confirmation email from the U.S. Coast Guard to NOAA Lt. Ryan Wartick, one of Coast Survey’s navigation managers. “Thanks for the great work!”

The problem began in early February, when an outbound tug struck and dragged a very large buoy and its anchor to an unknown location in the vicinity of Chesapeake Bay’s Thimble Shoal Channel. The U.S. Coast Guard closed adjacent anchorages because of the potential danger to navigation posed by the submerged buoy, affecting commercial vessel operations in the area.

On February 9, Lt. Wartick sat down with the U.S. Coast Guard, and other local and federal agencies, to arrange for Coast Survey mobilization in a collaborative effort to find the missing G “11” buoy. The Coast Guard asked Coast Survey to search Anchorage “A” on Friday, February 12, and provided a 45-foot vessel for our use.

AUV preparation
Lt. Ryan Wartick and MIST responder Robert Mowery prepare the AUV for deployment.

Coast Survey’s MIST responders Robert Mowery and James Miller were able to pack up the AUV in Maryland and drive to USCG station on Naval Little Creek amphibious base, where they set up, calibrated, and hit the water on February 12 – and promptly located five potential targets, one of which looked especially promising.

buoy
AUV’s image of buoy

This side scan imagery, acquired by the Hydroid REMUS 100 AUV during the Coast Survey MIST initial search on February 12, shows the sunken buoy – although, at that time, the team was not 100% confident it was the buoy. The intensity of the sonar return and the dimensions of the target strongly supported their suspicion that this was the buoy, but the target was at nadir on the side scan profile, which introduces uncertainty in this type of system. They did, however, deem it the most likely among the five possible targets revealed by the AUV data.

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Fortunately, NOAA Ship Ferdinand Hassler was departing Norfolk on February 17, on their way to their survey project for the approaches to the Chesapeake, and so they made a slight adjustment in their route. The ship’s hydrographers used their multibeam echo sounders to check the targets, based on the MIST AUV data, and they confirmed that the top AUV target was indeed the buoy. The multibeam data also verified that none of the other search targets pose a danger to navigation or risk fouling an anchor for ships in the anchorage.

With the confirmation, the U.S. Coast Guard was able to remove the buoy and re-open the area for maritime traffic.

Buoy is recovered.
Buoy is recovered.

The Coast Survey Development Lab has been evaluating the use of autonomous underwater vehicles as tools for hydrographic surveying in support of NOAA’s nautical charting mission. The use of AUVs, in collaboration with NOAA’s manned survey fleet, could greatly increase survey efficiency. Additionally, as this response confirmed, their flexible deployment options make AUVs a valuable tool for marine incident response.