Most of us spend our days on dry land and devote little thought to boats, ships, and their  associated propulsion systems and carbon footprints.

If we did, however, shipping-focused investor Stephen Petranek of venture firm Ocean Zero has some troubling statistics to share.

First off, we might consider the roughly 100,000 fuel-guzzling cargo ships that traverse the world’s oceans. Collectively, he estimates, they emit more CO₂ into the atmosphere each year than all the airlines in the world.

Motorized boats are also environmentally awful. The worst offenders can emit as much as 25% of their fossil fuel into the atmosphere and water. And if you look at cargo ships, ferries, fishing vessels and small recreational boats collectively, per Petranek, they probably produce at least 7% of global CO₂ emissions.

A sea of startups

Naturally, startups and their backers believe we can do better. And in the past few years, they’ve raised quite a bit of capital to prove their case.

Per an analysis of Crunchbase data, recently funded companies dedicated to improving the performance and reducing the carbon footprint of ships and watercraft have collectively raised more than $1.1 billion to date. They’re using that to further research and commercialization in areas from electric motors to wind-powered cargo shipping.

For a sense of where the money is going, we aggregated a list of 23 companies funded in the past two-and-half years with a focus on nautical innovation.

Electric propulsion

Startups developing electric-powered watercraft and propulsion systems picked up the biggest chunk of funding.

To wit, the largest investment recipient on our list is Seattle-based Pure Watercraft, which makes electric outboard systems, small boats and larger pontoon boats that it describes as zero-emission and nearly noiseless. Pure has raised over $200 million to date, with General Motors as a lead backer.

Stockholm-based electric boat maker X Shore is also an investor favorite, with over $100 million in funding to date. It picked up $29 million in fresh funding last year, shortly before launching its latest boat, the X Shore Pro, for maritime professionals. Another well-funded player in the space, Los Angeles-based Arc Boats, says it has sold out its initial electric cruiser, Arc One.

Boats with wings are another approach. Taking a lead role here is Rhode Island-based Regent, which is making electric seagliders for coastal transportation. Its flagship Viceroy model seats 12 and has a top speed of up to 180 miles per hour.

While building and scaling electric watercraft entails a lot of technical challenges, the sales pitch at least isn’t hard. If the price is affordable, who wouldn’t prefer a quiet, sleek-looking, fast boat that doesn’t require smelly, polluting fuel?

The challenge ahead, as with any manufactured product, is achieving the cost and quality control that enables major scaling.

Cargo

While adoption of electric boats will deliver a not-insignificant environmental upside, Petranek is more enthused about startups with applications in cargo shipping.

“If you wanted to go after a really big gigaton improvement in carbon emissions, probably the biggest thing you could do is go after ships at sea,” he said.

After all, by volume it’s estimated that around 90% of goods traded between nations travel on ships. Carriers range from fuel-laden tankers to bulk cargo ships bearing commodities like grain, to the massive container vessels that are a familiar sight to residents of port cities.

While technologies exist that could make a major difference, including electric propulsion systems, onboard solar panels and fuel-saving sails, Petranek said shippers haven’t made strides in adopting them. Looking at startup funding tallies, however, it’s clear that a number of upstarts are looking to try.

Among the more heavily funded is Ayro, a French Ocean Zero portfolio company that develops an automated, self-raising and lowering wingsail system that may enable ships to greatly reduce their fuel consumption. Meanwhile, 2-year-old Fleetzero out of Alabama, is a relative newcomer, with $15.5 million in known funding to date. It is developing technology for long-range zero-emission electric container ships.

Staying afloat

Nautical startups and their backers are an ambitious bunch, even among entrepreneurs. To prove out their visions, most will not only have to develop cutting-edge technologies, but manufacture at scale and gain a foothold in large, entrenched marketplaces.

That said, it doesn’t appear anyone expects the path ahead will be easy. As they scale and seek ever-larger financing rounds, hopefully investors will sustain commitments to keep the best afloat.

Related Crunchbase Pro list:

• Funded Nautically-Focused Companies

Illustration: Dom Guzman