Blake Anderson is the harbormaster at the Santa Cruz Harbor in California. As harbormaster he oversees all the operations of the harbor, harbor patrol staff, which includes search and rescue, law enforcement and public safety. He also oversees administration of about 1000 boat slips and day to day operations of the harbor. 6 years ago, Blake was faced with the challenge of rapidly mapping the constant shifting sand shoals in the harbor and turned his attention to BioBase as a potentially rapid mapping system
Sonar technology continues to improve bringing anglers and aquatic managers better, more clear pictures of the underwater environment on which they are so intently focused. Launched in 2011, BioBase’s EcoSound technology was the first cloud aquatic mapping system designed to process sonar logs from off-the-shelf Lowrance® sonar and create maps of bathymetry, aquatic vegetation biovolume, and bottom hardness for aquatic resource professionals. Today, BioBase is the leading cloud software solution for automated lake and coastal seagrass mapping.
Between 2011 and 2014, the algorithm underwent five major revisions. The bottom hardness algorithm has undergone two major revisions, with the last one in 2014. Thus, our code base was due for an overhaul in order to maintain performance and compatibility with newer generation Lowrance and Simrad sonar. This refactoring effort was also an opportunity for us to improve the vegetation and bottom hardness algorithms. Many of these improvements also carry over sister consumer technology C-MAP Genesis, which uses many of the same algorithms and backend processing architecture
In the 8+ years BioBase has been in service, we’ve seen our share of sonar logs and maps (both good and bad). We’ve learned some things and improved back-end processes that have resulted in you getting better maps processed faster. But we’ve also learned from you, our users, about strategies and techniques that result in better outcomes, and what to avoid. Here are eight of those lessons learned:
1. Good transducer installation is critical
You could be the most experienced hydrographer in the world and execute the perfect survey design, but your map will be mostly worthless if your transducer is not securely attached to your boat or is slanted at an angle. We’ve devoted a fair amount to this topic in previous blogs, so we won’t dwell on it here. The two key take aways are: 1) ensure the transducer is installed straight in all directions keeping in mind the slant of the hull in the water fully loaded. Replicate that tilt with your tongue jack when installing your transducer. 2) Install the transducer where the flow of water is smooth and laminar over the transducer face at all speeds. If you lose your transducer signal as the boat speeds up, you probably have an issue with cavitation (water turbulence) around the transducer face. Adjust the transducer height (sometimes only a very small amount) or move it away from rivets or anything else near the hull that could cause cavitation. One of the benefits of working with consumer devices like Lowrance and Simrad is that there is a wealth of online self-help resources and service centers that can help you install your transducer correctly. A simple Google Search “Lowrance Transducer Installation” will turn up all the resources you need. This one from Lowrance is one of our favorites. If you have multiple survey boats and want to make your unit portable, I strongly recommend purchasing and installing multiple transducers on all of your boats rather than a portable transducer bracket. In the grand scheme of things, consumer-sonar transducers are cheap and the consistent results you will get from a firmly mounted transducer is worth it!
Figure 1. Example of a slanted transducer and what affect it has on BioBase maps. A simple Google Search of “transducer installation” will turn up many very good self help resources about how to properly install your transducer.
