Steven Fox

Managing Partner @ Propeller | Ocean <​> Climate

📍 United States🔄 Updated September 2026💼 14 investments📅 8 years investing🗓 Last invested Jun 2025
Angel investor🌍 United States
14
Total investments
8
Early stage
1
Mid stage
0
Late stage
8y
Years active

Portfolio

13 investments · sorted by recency
All investments
Early stage
Mid stage
Late stage
Investor
Jun 2025
Nexxa builds specialized AI for industrial engineering in heavy project industries. Project industries like railroads, energy, construction, mining and others rely on highly educated industrial engineers to function. Today, industrial engineers have to do their work in a fragmented, sometimes outdated technology stack. Nexxa delivers AI agents that understand the technical work and augment the engineer in their most critical, but repetitive work. Our vision is to build an AI system that works with the engineer from scratch and accelerates engineering productivity without any pre-training.
Board Member
Dec 2024
Vema Hydrogen will revolutionize the hydrogen industry by producing Stimulated Geologic Hydrogen, offering the world Clean, Abundant and Cheap H2 to help decarbonize the planet .
Investor
Dec 2024
Indeximate Ltd, are a climate tech startup, based in the UK, formed in 2022, dedicated to preventing the failure of subsea power cables. We apply highly novel analysis techniques to inform clients on the risk facing their assets. We have developed IP in directly extracting measurements of cable integrity / weakness and novel techniques to host years of clients fibre optic sensing data - all re-interrogable.
Investor
Sep 2024
Orpheus Ocean is revolutionizing how humanity explores Earths final frontier. Were building a deep ocean intelligence service, powered by a constellation of autonomous assets, for the next wave of the blue economy. Our Orpheus AUV is the worlds first vehicle designed for scalable & agile access to deep ocean environments, as well as autonomous seafloor interaction for high resolution survey and sample return. Get in touch to discuss how we can help streamline your benthic data needs.
Investor
Jul 2024
Our technology mimics the earth’s natural carbon cycle to capture CO2 and store it in the ocean. As a key component in an enhanced sustainability system that produces energy from forest waste and helps improve the health of the oceans, we work with forest managers and suppliers, Indigenous Peoples and their organizations, and communities to ensure the entire process is demonstrably authentic to their values on sustainability. We believe in the benefit of ensuring we are both cost-effective and a trusted steward. Based in Nova Scotia, were thrilled to pioneer our ideas here.
Board Member
Feb 2024
Allium is developing the next generation of steel rebar coating to make our concrete infrastructure safer, long lasting, and more sustainable.
Board Member
Sep 2023
🚀 Who We Are: Were a team of PhDs and engineers, backed by top-tier AI and climate tech investors. Were pioneering multimodal foundation models that extend beyond the internet, tapping into the vast, untapped potential of satellite remote sensing and real-world data. 🌱 Our Vision: We believe in an intelligence that goes beyond memorizing the internet. Our models are trained on satellite remote sensing and real world ground truth data, and are used by our customers in nature conservation, carbon dioxide removal, and government to protect and positively impact our increasingly changing world. Our ultimate goal is to develop AGI of the natural world.
Investor
May 2023
Rewind helps mining companies improve their sustainability while generating carbon revenues. By sustainably sourcing plant biomass and preserving it in oxygen-free underground chambers, Rewind mitigates acid mine drainage, reduces land subsidence risk, manages methane emissions, and permanently removes atmospheric carbon. Rewinds solution is energy efficient, scientifically validated and accurately measured. Relying on its flagship project in a deep underground mine in Georgia, Rewind enhances mine closure and restoration, turning overlooked sites into nature-powered climate assets.
Investor
Mar 2023
Were reshaping the future of the wild salmon industry. We recognize the challenges it faces, from aging technology to volatile prices. It’s time for transformation. We redefine processing, making wild seafood more profitable while enhancing fisheries’ quality and value. This means economically viable harvesting, thriving communities, and strong fisheries. We promise to increase the value of wild fish with a process that is more efficient, profitable, and fair. Our solution ensures a positive, long-term impact on Alaska’s wild salmon industry.
early stageFisheries
Investor
Dec 2022
Aquatics mission is to reveal the invisible throughout the worlds waters. Based in Cambridge, Massachusetts, Aquatic is combining cutting-edge semiconductor technology, transformative ocean science, agile development methods, and modern fabrication approaches to create globally-scalable tools for tracking carbon, nutrients, and biodiversity persistently and pervasively throughout the world’s oceans – tools that are absolutely essential and desperately needed for monitoring and verification of ocean carbon sequestration, as well as a host of other global industries. From carbonate sensing to genomic surveillance, Aquatic is redefining what is possible to know underwater.
Investor
Dec 2022
We’re on a mission to create delicious, flaky, cultivated fish fillets indistinguishable from the fish you know and love.
Board Member
Feb 2018
Real Oyster Cults technology solution delivers a curated, fresh, farm-to-table oyster experience. The iOS app features both Atlantic and Pacific oysters from around the country and Canada. Handpick your favorites or try something new, all delivered right to your door with FedEx overnight shipping.
early stageFood & Beverages
Experience · 15 entries
All (15)
Investments (14)
Board (5)
2025
Investor
Jun 2025
Nexxa builds specialized AI for industrial engineering in heavy project industries. Project industries like railroads, energy, construction, mining and others rely on highly educated industrial engineers to function. Today, industrial engineers have to do their work in a fragmented, sometimes outdated technology stack. Nexxa delivers AI agents that understand the technical work and augment the engineer in their most critical, but repetitive work. Our vision is to build an AI system that works with the engineer from scratch and accelerates engineering productivity without any pre-training.
2024
Board Member
Dec 2024
Vema Hydrogen will revolutionize the hydrogen industry by producing Stimulated Geologic Hydrogen, offering the world Clean, Abundant and Cheap H2 to help decarbonize the planet .
Investor
Dec 2024
Indeximate Ltd, are a climate tech startup, based in the UK, formed in 2022, dedicated to preventing the failure of subsea power cables. We apply highly novel analysis techniques to inform clients on the risk facing their assets. We have developed IP in directly extracting measurements of cable integrity / weakness and novel techniques to host years of clients fibre optic sensing data - all re-interrogable.
Investor
Sep 2024
Orpheus Ocean is revolutionizing how humanity explores Earths final frontier. Were building a deep ocean intelligence service, powered by a constellation of autonomous assets, for the next wave of the blue economy. Our Orpheus AUV is the worlds first vehicle designed for scalable & agile access to deep ocean environments, as well as autonomous seafloor interaction for high resolution survey and sample return. Get in touch to discuss how we can help streamline your benthic data needs.
Investor
Jul 2024
Our technology mimics the earth’s natural carbon cycle to capture CO2 and store it in the ocean. As a key component in an enhanced sustainability system that produces energy from forest waste and helps improve the health of the oceans, we work with forest managers and suppliers, Indigenous Peoples and their organizations, and communities to ensure the entire process is demonstrably authentic to their values on sustainability. We believe in the benefit of ensuring we are both cost-effective and a trusted steward. Based in Nova Scotia, were thrilled to pioneer our ideas here.
Show all 15 entries ↓
Investment activity
2018–2025 · 14 investments
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