In oceanographic and bathymetric surveys, time is priceless. Hydro-Tech’s MS8200-IDH dual head multibeam echo sounder has proven a cost-effective solution, halving the survey time and doubling efficiency. Find out more about the MS8200-IDH in this case study from Hydro-Tech.
Multibeam Technology Overview
Conventional underwater 3D topographic surveys typically employ single-transducer MBES. However, these systems suffer from rapid degradation of edge beam quality, limiting effective coverage to approximately 4-6 times water depth. This limitation primarily stems from the significantly reduced effective array aperture at extreme beam angles. Consequently, large-scale underwater topographic mapping using single-transducer systems exhibits suboptimal efficiency.
System Composition
- 2 sets of MS8200 multibeam echo sounder
- 1 set of POS inertial navigation system
- 1 set of SVS1500 sound velocity sensor
- 1 set of SVP1500 sound velocity profiler
- HydroQuest 2024 display & control software and HydroNavi survey & data acquisition software
- Multibeam post processing software
- UPS Power supply
- 1 set of tide gauge
- 1 set of robust mounting pole
How does the MS8200-IDH reach 10 times the wide sweep width?
For the shallow water environment, the key factors that determine the coverage width are mainly the influence of edge beam width and reverse grazing angle. Due to the V-shaped array of dual heads, comparing with the single head’s installation mode directly toward seabed, the angular resolution of the edge beam angle is obtained. This is a huge improvement, shrinking by 4 times at 80 degrees, effectively reducing the edge beam footprint. According to actual survey, the effective swath reaches about 100 meters when the water depth is 10m.
How much better is the MS8200-IDH dual head compared to the single head?
Through the analysis of the effective swath of multi-beams, it is shown that the survey efficiency of dual head has been significantly improved comparing to a single head. However, how much can it actually be improved and how much human and material costs can be saved, these two questions can be answered through a set of test data: Single/dual head test comparison in 10m deep water.
Four survey lines of continuous dual-head multibeam data in the depth of about 10 meters water, which are surveyed from 11:31 to 14:46, taking 3 hours and 15 minutes, and the average speed was 5.5 knots (10.29km/h).
After the dual heads survey is completed, a single head surveyed in the same water area. In order to ensure the accuracy of the test results, the vessel, test personnel, auxiliary equipment, ship speed, etc. are all same as the dual head. After surveying and mapping, the swath of a single survey line with a single head is about 40m, mapped 2.47km² sea area, the survey time is 6.67h, and the total length of the survey line is 65.12km.
By comparing the measurement data of single/dual heads in the same water area, while ensuring that other factors remain unchanged, the survey time of the dual heads is shortened by 52.77%, and the total length of the survey line is reduced by 59.86%.
For a oceanology surveying and mapping project, the water depth is about 20 meters, the planned survey area is 600km², and the client estimates that the operation time will be 30 days. After our engineer communicated to the client and checked the environment, we reached a consensus and decided to use MS8200- IDH dual heads multibeam echo sounder to carry out the survey. In the end, it took 15.5 days to complete the planned survey mission. The total length of the survey line was 3700km, saving nearly 50% of the time for users to complete the project, truly get twice the result with half the effort.Â
Through the analysis of the swath, data and actual survey efficiency of the dual heads, the MS8200-IDH has nearly doubled the efficiency in large-area ocean surveying and mapping, saving more than 50% of operating time and investment costs.
Read the full case study here, or visit the Hydro-Tech website to find out more.
