The engineers designing a major bridge replacement needed the exact location of multiple pipelines buried below a fast flowing tidal bay. Divers and traditional methods were unable to provide information to the accuracy demanded by the designers. Utiliscope was retained to develop an approach and build the equipment to collect the data required. Utiliscope proposed a surface approach using a vessel equipped with thrusters for positioning, high precision GPS, side scan sonar, and custom pipeline detection electronics. Among many challenges was the fact that several of the pipes where buried up to 40 feet below the sea floor. The project also has a very tight schedule and narrow weather window. Utiliscope successfully outfitted the vessel with the one of a kind electronic systems and software developed for the project within the time allotted at our facilities in Virginia. We delivered the equipment to the client on site and conducted five days of training before turning the system over. The client used the system to map all of the utilities requested, and discovered a number of unanticipated utilities and structures which could have otherwise caused delays during construction. This project mapped over 300,000 feet of sub-seafloor pipes and represents our largest project of this type to date.