Oceanography | Vol. 38, No. 3
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OCEAN EDUCATION
DRIFTER CHALLENGE
A LOW-COST, HANDS-ON PLATFORM FOR TEACHING
OCEAN INSTRUMENTATION AND SENSING
By Charlene Xia, Bianca Champenois, Francisco Campuzano, and Renato Mendes
PURPOSE OF ACTIVITY
Ocean drifters provide essential data for understanding sur-
face currents. As part of a summer school on marine robotics,
we developed a curriculum around a low-cost drifter platform.
Using this curriculum, students explore oceanographic concepts
and engineering principles by designing the drifter with buoy-
ancy and drag considerations, deploying it, and analyzing data to
understand the relationship between Lagrangian trajectories and
Eulerian flow fields. They also investigate the influence of tides,
wind, and bathymetry on surface currents, comparing their obser-
vations with other datasets. At the same time, they build founda-
tional engineering skills, including waterproofing, circuit assem-
bly, sensor integration, and using hand tools, gaining practical
experience in applying these to ocean systems.
AUDIENCE
The curriculum we describe here is a hands-on project, developed
for the two-week MIT Portugal Marine Robotics Summer School in
the Azores, offered alongside a series of lectures. Twenty undergrad-
uates and graduate students formed six interdisciplinary teams with
expertise spanning engineering, fluid mechanics, robotics, marine
biology, oceanography, and computer science, a mix that fostered
cross-field learning. The project did not assume prior knowledge
of engineering or oceanography, and students drew on their indi-
vidual strengths to support team progress. The first week focused
on building and testing drifters. Students engaged with related lit-
erature and analyzed example designs as they developed their own
designs, considering how various choices were likely to impact per-
formance. The second week involved drifter deployment, data col-
lection, and comparison with other datasets and models.
BACKGROUND
Measuring and modeling ocean surface currents is critical for
understanding circulation systems that influence ecosystems and
human activities (McWilliams, 2016). Currents can be observed
via Lagrangian methods, such as tracking passively advected drift-
ers with GPS or inertial sensors, or Eulerian methods, using fixed
instruments such as current meters or radar systems. Early sur-
face drifters included simple “messages in a bottle” (Monahan
et al., 1974; Lumpkin et al., 2017), followed later by biodegrad-
able objects such as oranges (Muhlin et al., 2008; Bjørnestad et al.,
2021). Özgökmen et al. (2018) provide a comprehensive overview
of the history of drifters.
The two most common drifter designs employ either a holey-
sock drogue, which follows currents at depth, or an underwater
cross-shaped sail drogue that tracks near-surface flow. The Surface
Velocity Program (SVP) drifter is a well-known example of the
holey-sock design (Niiler et al. 1995; Haza et al. 2018), while the
Coastal Ocean Dynamics Experiment (CODE) drifter exemplifies
the cross-sail version (Beardsley and Lentz, 1987; Boydstun et al.,
2015). The CODE design, in particular, has inspired several well-
known adaptations, including the biodegradable drifters devel-
oped by the Consortium for Advanced Research on Transport
of Hydrocarbon in the Environment (CARTHE) to reduce cost
and environmental impact (Novelli et al., 2017; Haza et al., 2018;
Ganesh et al., 2025). More recent versions of both designs, such as
Areté, integrate additional sensors for temperature, salinity, and
acoustics.
Providing students with practical experience in tracking ocean
currents with Lagrangian drifters requires low-cost, approach-
able methods. Several educational initiatives use drifter-based
curricula, including “Go with the Flow,” “Get to Know a Drifter,”
the NOAA “Adopt-a-Drifter Program,” and classroom activities
such as “Exploring Our Fluid Earth: A Marine and Freshwater
Systems Curriculum,” and there are student drifter programs
(Gulf of Maine Association, 2014; Anderson, 2015). Our curricu-
lum focuses on giving students hands-on experience in building,
deploying, and collecting data from drifters with a cross-shaped
sail drogue design.
DESIGN, MATERIALS, AND ASSEMBLY
The drifter consists of two components: a mechanical structure and
an electronic system. The learning goal is for students to under-
stand how the mechanical design influences the drifter’s water-
following capability, durability, and stability, and to learn how the
electronic and software systems manage power, sense properties,
and enable communication. Instructors provide students with one
example design using the available materials (Figures 1 and 2).