We have been developing a variety of low-cost modifications to the original “CODE surface drifter” designed by Russ Davis in 1982 for the Coastal Ocean Dynamics Experiment (CODE, see reference below). We keep the basic configuration/size the same in order to maintain the oceanographic-standard drag but try to use materials available at any hardware store. The idea is that the drifter can be built in any high school shop class, for example. It is a project in materials science. The more eco-friendly bamboo-framed “Cassie Drifter” and the wood-sail “Emily” drifter developed during the summers of 2013 and Winter 2015, respectively, are just slight variations of previous models. The “Rachel” and the “Eddie” drifter were our standards for many years but the full list of models is listed under the “Drifter History” tab. They all have a cross-sectional area of approximately one square meter and, since the electronic package is getting smaller, we have been able to further reduce the windage with each new design. The transition to using more biodegradable materials has been a real challenge. Our current drifter model in use is the aluminum-framed “Irina” drifter, and we recently began using reinforced spars that seem to bend much less easily.
There are many different kinds of drifters, for surface drifters we use cruciform shape (see Irina, Eddie, Bamboo versions) and most recently began testing a star-shape bamboo drifter. We also recently completed the directions for our turtle drifters, designed to imitate “cold-stunned” turtles. Technically these are another type of surface drifter.
To study deeper ocean currents, we also make and deploy drogue drifters. Like most of the drifters used by oceanographers, these have sub-surface “drogues”. We construct them with a small surface float which holds the transmitter and provides buoyancy for the drogue. We typically tether the drogue made from a series of “toddler play tunnels” sold online or at kids’ stores at about 12 meters depth using 1/8 inch stainless wire. The top part of the drogue is fitted with a 3-point bridle and the bottom is weighted to keep it vertical in the water column. While the “Tim” play-tunnel drogues are still undergoing testing, the results thus far look good.
Davis, R. 1985. Drifter Observations of Coastal Surface Currents During CODE: The Method and Descriptive View.J.Geophys.Res.,90,4756-72.