<p>This paper focuses on the implementation of new techniques for bathymetric inspections. The scope is the exploitation of sensors, usually and commonly used for navigation, namely the altimeter and the Forward Looking Sonar (FLS), for identifying objects which are laying on the sea floor. In this particular framework, the low spatial resolution and coverage of these sensors have been enhanced through the application of classical computational geometry. The altimeter and the FLS are part of the most common underwater navigation systems, and they are vastly mounted on Autonomous Underwater Vehicles. Although they are not designed for this kind of accurate measurements and for 3D spatial reconstruction, they are quite cost-effective if compared with standard multibeam acoustic systems. Developing a technique for exploiting such an affordable low cost and widely used sensor will empower the Cultural Heritage community of users, giving a feasible opportunity to perform effective archaeological campaigns also within small funded projects.</p>