Little Boat, Big Impact

By Luke Carothers

Along the Texas Gulf Coast, the construction and expansion of ports is a continually-active process. As one of the busiest corridors in the world for shipping, ports along the Texas Gulf Coast are actively working to update infrastructure and facilities to support a massive flow of traffic. McCarthy Building Companies has worked with a number of ports along the Texas Gulf Coast to do just this. McCarthy has continually worked with Port Houston for 30 years, and is currently undertaking projects for Port Freeport as well as demolishing and constructing a strategically important dock for Port Beaumont.

Over their decades in working with ports along the Texas Gulf Coast, McCarthy has been in a constant state of innovation in construction, and has developed technologies that help make projects safer while saving time and money. Their most recent development in this regard is certainly lacking in size, but that hasn’t stopped it from making a big impact on projects in the short time it has been deployed. McCarthy has recently started using a five-foot-long by three-foot-wide unpiloted survey vessel (USV) to assist with their port projects. Using sonar technology, the USV collects data on the seafloor and finds obstructions within the work area. The USV is also equipped with a sound velocity probe that reports the density, salinity, temperature, and conductivity of the water—all of which impact how fast sound waves travel through water, making data it collects more accurate.

Sarah Johnson, senior field engineer for McCarthy’s Marine Business Unit, says that the deciding factor for obtaining the USV was their project at the Port of Beaumont. In 2012, a wharf at the port failed due to an issue with the corrosion of steel piles. As such, a large part of McCarthy’s work at the Port of Beaumont has been demolishing the failed piles and concrete structures then subsequently installing new piles that will resist corrosion. Much of this demolition work is underwater, which is complicated by incredibly murky water that affords at most six inches of visibility. With the complications of access and visibility impairing safety and slowing progress, McCarthy’s team turned to the USV.

Prior to deploying the USV at the Port of Beaumont, divers on the project faced significant challenges and dangers from lack of visibility. According to Adeel Malik, vice president of estimating for McCarthy’s Marine Business Unit, the decision to use the USV at the Port of Beaumont stemmed from a need to map out the collapsed structure that lies beneath the water, adding that the decision to do so has had a significant impact from a safety perspective. The USV utilizes sonar and GPS for depth and horizontal positioning. When deployed, the USV is piloted around the work area and sends back a color map that indicates noticeable obstructions as well as differences in elevation. Additionally, the vessel produces a side scan sonar, which represents the area in more detail. Once the survey is complete, the data is post- processed to produce a detailed map of the space beneath the water.

At the Port of Beaumont, the ability to map beneath the water has proven especially useful as the age of the structure means that there aren’t accurate drawings from the original early-1900s structure. Without the USV, this made locating sections of the collapsed wharf exceedingly difficult. However, the USV’s accuracy has allowed McCarthy’s team to locate obstructions within inches, according to Johnson. After obstructions are identified, a crane operator is given the location directly via GPS, and the obstruction is removed in just a few hours. Malik points out that the USV has cut a significant amount of time out of the project as it eliminates the need to wait for dive teams to carry out their operations. Malik further adds that the USV is crucial in that it gives McCarthy’s teams the ability to assess problems and develop solutions in a much quicker manner, and the ability to connect the vessel’s data with GPS positioning means that work is much more accurate.

This USV technology has also shown additional capabilities outside of locating underwater obstructions. At the nearby Port of Freeport, the vessel was used to record underwater slope depth for toe trenching. Its deployment at Freeport verified slopes were at the correct location and angle, which ensured that ship propellers wouldn’t make contact with the ground. Johnson believes that, while early in its usage, the USV has potential to impact several areas of water-based infrastructure. One example is the work around existing and new pump stations. Many of these projects require extensive survey work, and Malik believes that USV technology can provide an accurate and quick solution to the surveying required—whether it is identifying underwater obstructions or verifying previous survey data. When it comes to surveying around pump stations and levees, Malik further points out that the development of this technology and its potential coincides with a 2018 bill that allocates $5 billion for flood protection in the state of Texas. With more work around flood protection infrastructure, USV technology has significant potential to positively shape the future of water-based projects in the AEC industry.

McCarthy Building Companies has long been involved in shaping port infrastructure along the Texas Gulf Coast. Likewise, the work they are doing now is laying the groundwork for port infrastructure projects in the future. In particular, the deployment of technologies like the USV are instrumental in shaping the way projects will look for years to come. Deploying technologies like the USV that introduce a vast shift in worker safety, efficiency, and accuracy is demonstrative of a commitment toward shaping a better work environment in the AEC industry.