In early April, we ran a set of experiments in the WHOI Coastal Research Lab tank to learn more about what kelp will look like in our split-beam sonar system. Better to have a “dry” run where everything is still, before integrating the sonar with one of the kelpbots, Snoopy! The 200 kHz/333 kHz active acoustic system was placed in the bottom of the tank, and we used it to look at sugar kelp and the types of line that will be used for growing kelp in MARINER. The scattering data showed different types of returns from kelp stype and blade, and provided us with information on how we might use quantitative measurements from the acoustic system to provide farmers with useful information on growth. We are now confident that even the weak-scattering blades will show up in the system, and that the line returns are strong enough to use as navigation cues in vehicle autonomy.