TOWED VEHICLES
Figure 1: Fast CTD
Our science typically demands knowing the time evolution of ocean flows simultaneously as their spatial structure. Autonomous vehicles such as gliders, surface craft and AUVs are improving rapidly, but it will be a long time before they will reach the speed and capability of a research vessel. Therefore, we are always seeking to improve our ability to rapidly tow sensor-laden vehicles behind a ship, while cycling them up and down to get “swaths” of profiles behind the ship as it steams along. We have a suite of such vehicles for different purposes. One must often trade between extremely light and fast vehicles that measure only a basic suite of variables such as the fast CTD (Figure 1), or SWIMS - the Shallow Water Integrated Mapping System (Figure 2) - which is towed much more
Figure 2: SWIMS
slowly but also measures velocity, oxygen, turbidity and other variables.
For the deepest tows such as that shown in Flows around Topography, oceanographers for years have towed the shipboard CTD sideways, called “tow-yos” because they are yoyo-ed up and down while towing. We are hard at work at the moment on a next-generation deep towed vehicle for Scripps ships that will feature a hydrodynamic body, a fiber-optic cable for high-bandwidth communications, and velocity and turbulence measurements (Figure 3).
Figure 3: Deep tow concept