Naismith Marine Services

Sub-bottom Profiling and High Resolution Seismic

When details of the structure of the sea floor are required we often turn to sub-bottom profiling. A “chirp” signal in the 2 to 24kHz range is typically used to produce a two-dimensional profile of the sea floor. Sand, mud, organic, oyster shell and other layers can be mapped. Core data and other geotechnical information are often used to correlate layers and determine the composition of the sea floor.

Equipment: Edgetech 3100-P sub-bottom profiling system with SB-216S or SB-424 tow vehicles

Oyster Surveys

Oysters are critical to the health of our bays and estuaries.  Oyster surveys are conducted using TPWD specification dredges, core, and other sampling techniques. Reports include oyster, bay bottom, and substrate.  Often there is a cost savings when we are tasked with the hydrographic surveying as well as sensitve resource surveys.  

Single Beam Bathymetry
As a mainstay of our work, single beam bathymetry uses an echo sounder to measure depths under the survey vessel. Tide and other factors are accounted for to produce data referenced to the appropriate datum. With proper calibration, the data is reliable and relatively inexpensive to collect. A dual frequency system is used to “see through” fluid mud or into the surface of the sea floor. Often, changes in the sea floor composition can be detected.

Equipment: Knudsen, ODOM CVM, or Hydrotrac

Multibeam Bathymetry
Multibeam bathymetry measures depths in a swath perpendicular to the direction that the survey vessel is traveling. The width of the swath is often twice the water depth or greater. When detailed knowledge of the bottom and its features are needed, multibeam provides a robust solution. Sand waves, trenches and structures can all be seen with multibeam.

Equipment: R2Sonic 2024, ODOM ES3, or Reson 8101

Side Scan Sonar Mapping
Another mainstay of our work, side scan sonar is an extremely efficient method to map the surface of the sea floor. Items from the size of a paint can to a sunken ship can be detected and mapped. Side Scan Sonar is often used in conjunction with multibeam bathymetry to assist in identifying features on the sea floor. Seagrass, oyster reefs and other natural features can be detected. Man -made objects that are lost or present a hazard are located and mapped using side scan sonar.

Equipment: Edgetech 4125-P system with 400/900kHz or 400/1250kHz towfish

Sediment Sampling

Vibracores, drop tube samples, grab samples, and other methods are employed to obtain sediment samples for a variety of projects. Ground truthing sub-bottom profile surveys or sampling for dredging projects are our most common sampling projects. 

Equipment: Custom in-house vibracore, drop tube, and hand sampling equipment

Structure from Motion Aerial Photogrammetry
Also known as UAV or "drone" mapping, the techniques have largely replaced conventional fixed winged stereo pair aerial photogrammetry.  Monitoring large or small areas of marsh and related coastal uplands is simply faster and less expensive. In addition, we survey the sea floor and channels to provide seamless data where the aerial techniques alone become unreliable.

Equipment: Various cameras, PIX4D software

Magnetometer (Hazard) Surveys
A magnetometer is one of the most reliable methods to locate unknown ferrous objects on or under the sea floor.  Normally used for locating pipelines and wrecks it has become common for dredging or pipeline projects.  

Equipment: Geometrics G882, Marine Magnetics SeaSPY

energy, oil & gas

Vessels and structures continue to grow larger and more complex.  We provide surveys for design, construction, dredging, moving, and monitoring.

Land Surveying, State Land Surveying

Coastal projects often require the adjacent land to be surveyed.  Coastal Boundary Surveys per 33.136 are required for any project that includes erosion protection.  With Registered Professional Land Surveyors and a Licensed State Land Surveyor on staff, we are able to provide any required surveys on land or submerged state land.

Cultural Resources Survey Support

Naismith Marine provides, vessel, side scan sonar, sub-bottom, and dive support for marine archaeologists.  Some projects in Texas bays require a cultural resource survey as part of the USACE permitting process.  The marine archaeologist runs the data collection from our vessel.  We supply the expertise needed to collect data exactly to his or her guidelines meeting all of the THC & USACE requirements.

Tide, Current, Temperature, Salinity, Wind Speed/Direction

Tide and wave action is critically important to coastal facilities. We can deploy and monitor electromagnetic current meters (single point) and Acoustic Doppler Current Profilers (profile). Over-the-side deployment may be useful in inlets and other waterways. We can detect and measure infragravity waves related to storm events. Temporary tide gauges can be installed on existing structures or we can drive small pile structures.

Equipment: Valeport, Sontek, Custom tide gauges

Hi-resolution Multibeam Surveys for Structures

In addition to sea floor surveying, multibeam echo sounders can be tuned to provide hi resolution images and point clouds of structures.  Dock faces, sheet pile walls, dolphins and other large structures are often scanned post-construction or prior to inspections.  Scour and shoaling can be precisely documented for comparison surveys.

Equipment: R2Sonic 2024

Underwater 3d Imaging

Areas under docks and harbor structures or for projects that require more detail, underwater 3d imaging may provide the solution.  A point cloud is produced that can be utilized to document details, check for damage / scour, or provide a three dimensional view of complicated structures.

Equipment: BlueView 3d mechanical scanning sonar

U.S. Army Corps of Engineers Wetland Delineation

Naismith Marine conducts wetland delineations according to methods approved by the US Army Corps of Engineers (USACE).    The area and extent of both wetlands and uplands are delinated within the survey area.  Naismith can also conduct High Tide Line (section 404 Jurisdcitional Limit in the absence of wetlands) and Mean High Water Line (Section 10 Jurisdictional Limit) delineations.  Naismith can also  coordinate with USACE to obtain approval for  delineations of potentially jurisdictional areas.

Beach Profile Surveys (Gulf and Bay)
Naismith Marine is the industry leader in beach profile surveying along the gulf coast. We custom build our high-precision sleds for work in the surf zone. Possibly just as important is our experience in working the “weather windows” when the best data can be obtained. Surveying from the back of the dune line to depth-of-closure in the shortest possible time provides a snapshot of the beach conditions.

Equipment: Custom built sleds and GPS-RTK receivers

engineering and construction

Increased trade, capacities, and canals lead to larger vessel size and deeper ports. Better design and fewer changes start with accurate and detailed site surveys.

Corps of Engineers Permit Support / Sensitive Resource Surveys
Naismith Marine works with the top coastal engineering firms to support the permit process.  Wetland delineation, jurisdiction, oyster, seagrass, and other surveys are routine.  We can assist landowners and commercial interest through the permit process for docks, piers, bulkheads, pipelines, wells and other small projects that do not require engineering.

Naismith Marine Services Hydrographic Geophysical Environmental

beach, bay & marsh

We live, eat & breathe coastal habitats. Whether it is simple bathymetry or complex research / monitoring, we have the solution.

Seagrass Surveys

Seagrass is a nursery habitat for shrimp, crabs, fish, and other wildlife.  Naismith Marine conducts sensitive resource surveys used in the Corps permitting process.  Seagrass surveys report the absence or presence of seagrass, species, and, density of the seagrass bed.  Often there is a cost savings when we are tasked with the hydrographic surveying as well as sensitve resource surveys.