Propeller VC — Full Portfolio

Allium Engineering designs and manufactures a stainless steel cladding process for steel rebar that prevents corrosion, extending the lifespan of construction structures while lowering cost and carbon emissions.

CleantechConstruction TechNew Materials

Steven Jepeal(Cofounder)Samuel McAlpine(Cofounder)

Co-investorsAera VCBay Bridge Ventures ClimateCastor Ventures (an Alumni Ventures Fund)Creative Destruction Lab (CDL)

Aquatic Labs develops solid-state, semiconductor-based water sensors that measure parameters such as pH, total alkalinity, conductivity, and temperature without consumable reagents, paired with a data pipeline for real-time insights.

CleantechHardwareIoT

Co-investorsBURNT ISLAND VENTURESFuture Planet Capital

Banyu Carbon develops a photochemical carbon capture process that uses sunlight to release CO2 from seawater, which naturally absorbs atmospheric carbon, for storage in geologic formations or industrial use.

CleantechClimate TechDeep TechSeattle, US

Alex Gagnon(Executive Officer, Director)Julian Sachs(Executive Officer, Director)

Co-investorsCarbon Removal Partners

Blue Energy develops scalable small modular reactor (SMR) technology to deliver nuclear power at scale.

CleantechClimate TechDeep TechEnergyHardwareWashington, US

JakeTomJacob Jurewicz(Executive Officer, Director)Thomas O'Neill(Executive Officer, Director)

BoardOrin Hoffman(Director)Michael Kearney(Director)in

Co-investorsAt One VenturesAngular VenturesNucleation CapitalTamarack GlobalThe Engine VenturesFounders Fund+3 more

Calcarea develops a reactor based on "Accelerated Weathering of Limestone" that captures CO2 from point sources—particularly marine on-board applications—and converts it into stable oceanic bicarbonate for permanent storage.

CleantechClimate TechDeep Tech

Co-investorsAzolla Ventures

CarbonRun restores acidified rivers by adding crushed limestone to reduce acidity, which converts CO₂ into stable bicarbonate that rivers carry to the ocean for long-term storage, while improving water quality and fish populations.

CleantechClimate TechImpact & Social GoodDartmouth, CA

Co-investorsPanache Ventures

Circle Seafoods operates floating processor barges that freeze wild-caught seafood at ultra-low temperatures at sea, providing refrigeration, sorting and grading technology, and cold storage, along with amenities for fishermen.

Circular EconomyFoodTechHardwareLogistics & Supply ChainSitka, US

Gene Patrick Glaab(Executive Officer, Director)Charles B. Campbell(Executive Officer, Director)Eren Barclay Shultz(Executive Officer, Director)

BoardVictor Kiam(Director)

Ebb develops electrochemical water treatment technology that recovers freshwater from desalination brine while removing carbon dioxide and producing industrial chemicals.

CleantechClimate TechSan Carlos, US

Ben Tarbell(Executive Officer, Director)Matthew Eisaman(Executive Officer, Director)

BoardKevin Tidwell(Director)Mike Biddle(Director)inGabriel Kra(Director)in

Co-investorsAutodesk FoundationCongruent VenturesEvok InnovationsPrelude Ventures

Indeximate is a UK technology company offering fibre-optic sensing and monitoring for subsea cables in the offshore wind industry.

CleantechDeep TechEnergy

Navier builds the N30, an electric hydrofoiling boat with a carbon fiber hull, flight-control software, and electric propulsion that lifts the vessel above the water for a smoother, quieter, and more efficient ride.

CleantechHardwareMobility & Transportation

Sampriti Bhattacharyya(Founder & CEO)

Co-investorsNextView VenturesScript Capital

Nexxa builds AI agents that capture a company's decision logic, institutional knowledge, and operational judgment, then execute tasks by writing directly into the company's systems of record.

AI & Machine LearningEnterprise SoftwareSaaSSunnyvale, US

Philipp Wehn(Founder)

Co-investorsBeat VenturesConstruct CapitalUntapped VenturesAugment Ventures

Orpheus Ocean designs, builds, and operates autonomous underwater vehicles (AUVs) for seafloor data collection and monitoring.

Deep TechHardwareRobotics

Co-investorsJetstream

Rewind performs permanent carbon removal by backfilling mine voids with sustainably sourced biomass, which simultaneously fulfills mine reclamation obligations for the mining industry.

Circular EconomyCleantechClimate Tech

Co-investorsMensch Capital PartnersYes VCZORAAndreessen HorowitzFirst Round CapitalH.I.G. Growth Partners+2 more

Vatn designs and manufactures modular, low-cost autonomous underwater vehicles (such as the Skelmir S6 and S12) with proprietary autonomy, navigation, and control software for GPS-denied and contested maritime environments.

Defense TechHardwareRoboticsPortsmouth, US

Geoff ManchesterFreddie Mills

BoardThomas Hendrix(Director)inGeoffrey Manchester(Director)Thomas Hennessey(Director)Nelson Mills(Executive Officer, Director)

Co-investorsBeyond CapitalBlue CollectiveCapital FactoryCentre Street PartnersChampion Hill VenturesCoalition+14 more

Vema Hydrogen develops Engineered Mineral Hydrogen (EMH), a patented production method that stimulates naturally occurring subsurface geochemical reactions in ophiolite and BIF rock formations to produce carbon-free hydrogen at under $1/kg.

CleantechClimate TechEnergy

Pierre Levin(CEO)Colin McCulley(Director of Operations)

Co-investorsPace VenturesExtantia Capital