If you look closely at any U.S. coastal nautical chart, you’ll likely find that the areas closest to the shore, shoals, and rocks do not have updated depth measurements. In many areas, safety concerns prohibit the use of NOAA ships or launches to survey the shoalest depths. In many areas, the water is too murky to be mapped with the airborne lidar systems used in clear waters. Now, however, charting those shallow areas is about to get safer, thanks to recent purchases of small, commercial off-the-shelf, unmanned surface vehicles.
This summer, NOAA Ship Thomas Jefferson will deploy a “Z-Boat,” offered by Teledyne Oceanscience out of Carlsbad, California.
The Z-Boat complements the ship’s existing hydrographic toolkit.
- Thomas Jefferson uses its multibeam echo sounder to measure depths from 45 to 1000 feet.
- For shallower and more constricted waters, the ship’s two hydrographic survey launches with multibeam echo sounders efficiently and safely survey areas from 12 to 200 feet deep.
- With the new Z-Boat (using a single beam echo sounder), Thomas Jefferson can measure depths in areas as shallow as one foot, and get that data into processing almost immediately. The boats are highly maneuverable, turning in their own 5.5-foot length, meaning they can get much closer to piers, pilings, and the shoreline than a full-sized launch.
This new capability is important to improving charts for smaller vessels operating near the coast, and in the inlets, bays, and harbors so critical to many small coastal towns. In the 1930s, the Roosevelt Administration – through its massive Depression-era public works program – hired hundreds of men to survey shallow Intracoastal Waterway areas. However, NOAA has done very little survey work in shallow water in the 80 years since then. Not surprisingly, there is a backlog of reported shoals, rocks, wrecks, and obstructions in shallow water, leading to an increased risk of grounding for those smaller vessels. Knowing the depth in these inlets is also important to accurately predicting coastal inundation during storms.
Thomas Jefferson, with the support of NOAA’s Office of Marine and Aviation Operations’ innovative platform program, plans to use two Z-Boats this summer in Massachusetts to investigate shoals and rocks in Buzzard’s Bay and Vineyard Sound. This December, they will use them in a project near Chesapeake Bay.
“Coast Survey has been exploring the use of autonomous underwater vehicles – AUVs – to support nautical charting for over a decade,” explains Rear Admiral Gerd Glang, Coast Survey director. “Unmanned surface vehicle – USV – technologies have advanced in recent years, and NOAA is now also exploring these for our hydrographic operations. The Z-Boat is one of several unmanned surface vehicles that we are experimenting with.”
Through a hydrographic survey contract with NOAA, TerraSond (Palmer, Alaska) is using a USV in addition to their traditional manned boats. (See this article in Marine Technology News.)
One of the benefits of using off-the-shelf vehicles like Z-Boats is that hydrographers are able to calibrate the boats and put them into use quickly, without the need for additional installation and integration of a survey system. Thomas Jefferson took delivery of the boats on August 13. They now have qualified the system for hydrographic use, developed first-generation deployment and retrieval systems, and trained a cadre of Z-Boat “pilots.”
“Two weeks from delivery to a calibrated system with trained operators is a significant achievement,” said Capt. Shepard Smith, Thomas Jefferson’s commanding officer. “We have already used them to conduct a small survey in Newport, Rhode Island, and we are thrilled with the new capability this boat will give us in our coastal projects.”
Thomas Jefferson will operate the boats from a control station on the ship or one of their launches. Depending on the circumstances, technicians have several options to control the boats, by using: 1) a handheld remote control; 2) a networked radio link with one-mile range; or 3) an onboard autonomy module. NOAA is working with Teledyne and with researchers at the University of New Hampshire-NOAA Joint Hydrography Center to develop improvements to the boat’s autonomy system that will permit it to gradually work more independently of the operator. With more Z-Boat autonomy, survey ships can operate a larger fleet of boats without adding additional operators.
Capt. Richard T. Brennan, chief of the Coast Survey Development Laboratory, puts this move into a strategic technology context.
“NOAA envisions unmanned and autonomous systems working in conjunction with our manned systems, deployed and controlled from our hydrographic survey ships,” Brennan explained. “The Z-Boats are the first step towards unmanned surface vehicles. We are looking forward to the lessons learned to drive further innovation in communications and automation technology.”
Thomas Jefferson will be exploring other options for the boats. For instance, Z-Boats have an onboard streaming video camera, so the operator can see what the boat “sees” in real-time, raising the possibility of additional uses beyond depth measurements. And although these Z-Boats are fitted with single beam echo sounders appropriate to very shallow water, there is an option to fit them with side scan sonar, or a multibeam system, for other applications.
“Deploying the Z-Boat from the Thomas Jefferson is a significant milestone for the NOAA fleet,” said Rear Admiral David Score, director of the Office of Marine and Aviation Operations. “In the coming decade, these types of unmanned systems will become the norm. We will be able to build on Thomas Jefferson’s experience in unmanned systems as we expand these programs into the broad range of scientific observations that the NOAA fleet provides.”
The ship is selecting the nicknames of the two Z-Boats. Go to the NOAA Ship Thomas Jefferson Facebook page, and see what names they are considering!