55 With most of the world’s cities and a growing proportion of the global economy directly connected to our oceans, it is inevitable that marine territories are not only becoming more polluted but are being exposed to multiple different ecological threats, each needing its own solution. For instance, litter in canals, estuaries and shorelines can be collected autonomously by a single small boat such as NXInnovation’s NX 100 Enviro USV (issue 48, February/March 2023) or a large vessel acting as the mothership for a team of UUVs and UAVs, as in SubseaTech’s SeaCAT UGV (issue 52, October/ November 2023). By contrast, algal blooms and other biological threats can be identified and measured to aid in countermeasures using a USV such as RanMarine’s Wasteshark (issue 11, December 2016/ January 2017) or an AUV such as Xylem’s i3XO (issue 42, February/March 2022). Also, chemical spills can be similarly sampled and identified by an uncrewed skimming boat such as that created through the partnership of Sea Machines and the Marine Spill Response Corporation (issue 34, October/ November 2020). Harbours are areas of high overlap between different ecological threats, where litter as well as chemical and biological agents can spill into the waters every day. There is therefore a strong demand among harbour operators for autonomous systems that can monitor and clean their waters in a repeatable, cost-effective and time-efficient manner. Since its founding in 2019, Spanish autonomous systems manufacturer GPA Seabots has been supplying and customising its USVs to recreational marinas and commercial industrial ports to help keep their waters clean. It has also designed and produced filtering buoys made from microplastics, along with other ecologically minded solutions. The bulk of its customers are harbour authorities who want a combination of autonomous waste clearing, oil spill cleaning and hydrographic surveys. Three USV designs comprise the company’s port monitoring and restoration solutions, each including the ability to sample for hydrocarbons as well as remove them from water surfaces. Seabots USVs GPA Seabots’ principle tool for collecting waste and liquid pollutants is the SB 100 Cleaner, a fully electric catamaran USV built from fibreglass composite and running on a LiFePo4 battery with an estimated lifespan in excess of 2000 cycles. The USV measures 103 x 75 x 55 cm, with a 14 cm draft. It weighs 25 kg empty and can be loaded with up to 12 kg of payload. The ‘payload’ includes the equipment for cleaning as well as the material gathered during cleaning. The equipment comprises a basket installed between its two catamaran hulls for scooping up litter, and industry-standard oil absorbent pads that can be installed and arranged about the USV in different ways to optimise the removal of petrochemicals from the water. The company’s data-gathering USV is the SB 100 Pro, a vessel almost identical in size and construction to the Cleaner. Minor differences include a slightly heavier empty weight of 31 kg, an increased draft of 15 cm, and a maximum payload of 15 kg. These give it a maximum endurance of 3 hours, while the Cleaner’s is 3.5 hours. “The Cleaner was our first prototype, and the lower half of its catamaran shape was designed to fit what we call our ‘pelican mouth’ basket for collecting solid trash from the water’s surface,” explains Javier Sanchez Barchino, manager at GPA Seabots. “But we also wanted something that would clean oil from water. That’s an underserved use case, but a really important one for protecting marine life around ports and ships where oil spills happen by accident every day. “We started by putting oil absorbers inside the pelican mouth, or wrapping them horizontally around the USV’s body, but quickly discovered through real-world testing that if you direct your USV into a patch of floating oil, you don’t really catch any oil at all. If anything, you just split the oil in two because of the density of the water you’re pushing before you. So we’ve learned to orient the oil catchers in different ways. “The Pro meanwhile weighs more than the Cleaner because it carries heavier, more expensive electronics for precise surveying, including more robust navigation and interfacing systems.” In addition to these two, GPA Seabots has designed, prototyped and demonstrated a larger USV, the Harbot. It was developed after requests GPA Seabots SB 100 | In operation Rory Jackson reports on how these systems answer growing calls from port authorities for robotic USVs that can carry out clean-ups as well as survey duties masters Uncrewed Systems Technology | December/January 2024
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