Propeller

Propeller is an early-stage venture fund based in Boston with a $117M fund focused on climate-tech startups at the ocean-climate nexus, making seed-stage investments averaging $500K-$2M and Series A investments up to $19M. Co-founded by former HubSpot CEO Brian Halligan and partnering directly with Woods Hole Oceanographic Institution for science-backed deal sourcing, Propeller invests in ocean carbon capture, ocean-based renewable energy, maritime decarbonization, biotechnology, and marine conservation. The firm particularly values ocean-science-based founders and companies leveraging institutional IP for tech transfer, and operates an Ocean MBA networking program connecting ocean science and entrepreneurship. Founders should have deep domain expertise in ocean science or be positioned to commercialize research-backed solutions.