In late August 2022, following the successful playtest of our board game on human-wildlife conflict, my colleagues and I embarked on another exciting journey. We travelled down south from Bangalore, to the coastal city of Pondicherry for a collaborative field expedition. Our mission was to assess the feasibility of using ROVs for surveying and data collection in deep sea. Over the next three days, we explored the capabilities of our SoFar Trident along India's east coast, venturing to depths of up to 30 metres.
ROVs, or remotely operated vehicles, offer a unique advantage by allowing underwater exploration in waters that may be hazardous for human divers. We got our SoFar Trident, named Varuna through the WCS Underwater Exploration Program. It can be operated via a mobile app, with information relayed through cables connecting the ROV when in action underwater. These cables facilitate the transmission of command and control signals, enabling remote navigation of the vehicle.
On the evening of day zero, our teams gathered from different cities. It was a mix of familiar faces and new introductions, as some team members who had previously interacted met in person for the first time. We discussed our aims for the coming days. Additionally, a few members who arrived early took the initiative to secure the boat for the next day and determine our exploration locations.
Day one kicked off with a delightful discussion over South Indian breakfast at a local restaurant. Following this, we headed to the harbour to test Varuna at the deepest accessible point from the coast. During the brief waiting period as the boat and captain conducted their checks, we did a quick inspection of the ROV and discussed the feasibility of mounting a waterproof action camera onto the external surface of the ROV.
We set out from the dock at 9am, but faced challenges once the boat was in the Bay of Bengal. The water away from the shore proved to be turbulent and the midday sun quickly wore us down. We made two successful launches to the water, amongst others. We were able to view the sea bed clearly in one of the instances, when we directed the ROV using our boat’s anchor as the guide. But the challenges took an intense turn for our crew. Despite their familiarity with boat operations and a lack of previous seasickness episodes, the combination of choppy seas and the immersive experience of monitoring the Trident's live-feed on a screen induced nausea and severe seasickness. Therefore, once we had gained a rough understanding of the conditions involving high current flow and low visibility at these depths, over a period of three hours in the water; we decided to return to shore.
Drawing from our past experiences with other Tridents, we are well aware of the paramount importance of regular motor maintenance to prevent corrosion, even when the Tridents were not actively used in the field. Consequently, our first task once on land was to clean the motors and external body of the Trident with fresh water.
We spent the following hours recovering from the first half’s experience by consuming lunch and coconut water. In the latter part of the day, we tried testing by adding a payload to our ROV, specifically mounting an external camera. We wanted to assess conditions related to depth pressure, visibility, and camera housing. Initially, we utilised scuba divers’ tanks available at a local dive training facility for our tests. However, we encountered limitations due to the size of the tanks. Subsequently, following a suggestion from the trainers, we shifted our testing to a nearby swimming pool. The pool’s management allowed us to use their facilities for a fee, helping with our trials.
Testing the ROV with additional payload.
On the following day, we were better equipped to handle the now-familiar conditions of the field site. Armed with Avomine, we commenced our day an hour earlier than the previous day, affording us a total of four hours in open water. The ingestion of the anti-nausea medication proved highly effective, preventing any further episodes of seasickness and enabling the successful operation of the ROV. Our improved situation allowed us to deploy the ROV to even greater depths greater than 20m, broadening our exploration to new sites. Upon returning to shore, we fixed on our plans for the next day, which included simultaneous dives using the trident as well as a diver.
Spotting a Moray eel through the ROV.
The final day of our expedition proved to be the most eventful. During one of the deployments, we had one of our colleagues dive alongside the ROV. Their role was to guide the ROV away from the boat's anchor rope to prevent any entanglement and ensure a faster, precise ascent to the ideal location. These dives occurred in two distinct locations, with one of the sites known for its rich underwater life presence. The live feed from the ROV, which captured a diverse array of species, including lion's mane fish, moray eels, starfish, and more, generated contagious excitement among the team. Additionally, we strategically placed markers on the ocean floor to assess visibility and made an attempt mimicking a transect survey with the assistance of an underwater camera and a diver.
This mission has enhanced our understanding of the capabilities and limitations of marine robot technology for conservation research. The Trident’s capability shone when it employed its exploration mode. It was swift to respond to controls and was able to accommodate additional payloads through its mounting system. However, it falls short in conditions of low visibility and fast-moving currents, making it less suitable for missions requiring repetitive activities such as transects or seabed mapping.
We have also effectively acquired three hours of deep-water footage (exceeding 25 metres) that includes a record of marine biodiversity along India's east coast. This achievement was made possible by deploying the Trident, which navigated through changing currents and varying visibility conditions. Furthermore, this mission allowed us to assess the viability of the Trident ROV in real-world conditions, providing valuable insights into future research possibilities.