Multibeam Bathymetry at a Proposed Port Development Site in the Bahamas

Steele Associates specializes in high-resolution multibeam bathymetric surveys. Multibeam bathymetry is collected using an array of acoustic beams, while single beam sonar collects point data directly beneath the transducer. The multibeam echosounder (MBES) swath allows for greater sounding density, increased survey efficiency, and improved resolution. An MBES utilizing an inertial measurement and heading sensor provides enhanced accuracy and precision, improved data quality, and enhanced seafloor visualization over single beam bathymetry. Multibeam bathymetry is the preferred choice for most surveying and mapping applications and crucial to determine navigational clearance.    

SAMC performs multibeam bathymetric surveys for projects at U.S. Naval facilities, ports, offshore wind, subsea cables, Army Corps navigational dredging, and private properties throughout New England.

Single beam bathymetric survey for the Barnstable County Dredge in Chatham, Massachusetts
Single Beam Bathymetric Dredging Survey of Aunt Lydia’s Cove, Chatham, MA

Single Beam Bathymetry uses a single sonar beam to collect depth measurement data directly beneath the sonar’s transducer. Single beam is a straight-forward and economical approach to collecing depth measurements and generally better suited for shallow water surveys. Its drawbacks include limited data coverage of the seafloor, less data density, and the interpolation of bottom conditions in areas located between survey transects.

Steele Associates performs numerous single beam bathymetric surveys of shallow water bodies and rivers annually. We provide single beam bathymetric surveys for the Barnstable County Dredge, which maintains dozens of Cape Cod’s harbors, entrance channels, and waterways. 

SUBBOTTOM Survey Image by Steele Associates
Sub-Bottom Geophysical Survey of a Proposed Offshore Wind Terminal

Sub-bottom profiling is a marine geophysical survey method used to investigate subsurface sediment layers and features beneath the seafloor. Sub-bottom profilers use low frequency acoustic pulses to penetrate the seafloor and records the reflected acoustic return.  This data can reveal the physical characteristics of sediment and rock layers, and other features beneath the seafloor. `

Autonomous Underwater Vehicle Side Scan Sonar Inspection
Side-Scan Sonar Subsea Pipeline Inspection

Side-scan sonar uses high frequency, narrow acoustic beams to generate detailed imagery of the seafloor. Side-scan is particularly helpful in locating and identifying underwater features such as debris, wrecks, pipelines, cables, and navigational hazards. It is also well-suited for habitat mapping, fisheries surveys, bottom classification, and pipline inspection.

Side-scan sonar surveys are typically performed from a vessel using a towfish. Steele Associates also uses an Autonomous Underwater Vehicle (AUV) for higher resolution imaging of pipelines and other features of interest.

Vibracore sediment sampling
Vibracore Sediment Sampling from the vessel Noah Lane, Chatham, MA

A vibracore sediment sampling system consists of a stainless steel core tube and vibratory source. The vibracore system is typically lowered from a sampling vessel using an A-frame or deck crane. The vibratory source and weight of the unit allow the core tube to penetrate the seafloor without excessive disturbance. As the tube penetrates the bottom, a continuous column of sediment is collected within an inert core tube liner. The sediment is held in place by a stainless steel catcher assembly secured to the core tube. The retrieved core sample is carefully extracted from the tube and logged for laboratory analysis.

Steele Associates maintains multiple shallow-water sediment sampling vessels to support various collection methods. SAMC’s vessel Noah Lane is equipped with a hydraulic knuckle crane and dual antenna RTK GPS for high-accuracy positioning and water level elevation measurements.


  • Marine Magnetics
  • Subsea Positioning
  • ROV Video
  • Vessel-Mounted LiDAR
  • Cable and Pipeline Surveys
  • Aerial LiDAR and Photogrammetry
  • Vessel and Equipment Tracking
  • Offshore Positioning and Navigation Support
  • Autonomous Surface and Underwater Vehicle Surveys (ASV/AUV)
  • Water Quality Monitoring
  • Remote Sensing Fisheries Surveys
  • Vibrocore Marine Sediment Sampling
  • Data Analysis and Consulting Services