Fueled up

Some hard truths about the environmental impact of boat ownership

Daystar from above the Chicago River {PHOTO] @lynnbecker

We recently launched our 30 year old sailboat “Daystar” for her third season with us on the Caribbean green waters of Lake Michigan. We think she’s a real eye catcher of a vessel - sleek blue hull, gleaming teak wood accents with a tall mast sporting dazzling white sails that propel her through the waves using the power of the wind.

But one of the dirty secrets of many recreational sailboats is that they use a fossil fuel powered engine to move them around when the wind isn’t blowing. Daystar is one of them. Her “iron genny” is a 46 HP diesel engine that has, so far, reliably pushed our vessel for a total of over 3,100 hours during its lifetime. While listening to the engine rumble, I wondered whether I could calculate Daystar’s environmental impact using those numbers?

The “Westerbeast” that moves Daystar when the wind isn’t

The simple answer is no. Any human-made object includes some “embodied” or “up front” impact. This is the result of cutting down the trees, mining the minerals, lighting the factory and transporting the goods to make the thing in the first place. Then there’s the environmental cost of maintaining it, which as I’ve written here before is hardly insignificant.

However, in most cases extending the life of something is better than scrapping it and making something new. This is one reason we take care of the stuff we own. Plus, it’s generally cheaper in the long run. And it makes me feel good.

Daystar getting ready to splash

Back to the diesel fuel. Given the lack of prior owners’ records, it’s impossible to know exactly how many gallons of dino juice have sloshed through the engine’s fuel tank over three decades of service. On the other hand, this captain is a bit of an information pack rat. I can assure you that we consumed 40 gallons total in the two seasons we owned the boat.

Like any internal combustion engine, fuel burn will depend on a variety of conditions that are well beyond the point of this article to bother listing. If you’ve made it this far on the page, I hardly want to lose you down a bunny hole of power/torque/rev curves. However, the engine manufacturer has kindly provided a compelling graph from a 1984 sales brochure which displays the numbers we’re looking for. The estimate we’re going to use is 1.9 gallons per hour of running at 2,000 RPM. Don’t ask me to back all this up with my assumptions, since we’re just trying to get a rough number.

Burning a gallon of diesel fuel deposits about 22.2 pounds of carbon dioxide into our shared atmosphere. Let’s ignore the soot and other noxious pollutants for the time being. Let’s also not try to figure out why metric tons aren’t the same as “regular” tons. Tonnes vs. tons? And the abbreviations? Don’t get me started…. Simple math says 3,100 hours of run time at 1.9 gallons per hour = 59 mt of carbon, or approximately 2 mt per year. Our emissions have been significantly less, at 0.2 mt per year. Maybe we sail a lot more than the previous owners?

Since most people haven’t a clue what a metric ton of an invisible gas means on its own, myself included, allow me to share a few reference points. I’ve embedded the links to the data sources so you can mess around with the numbers yourself if you’d like:

• The average American is responsible for about 15 mt of CO2 equivalent per year

• Driving a 30 MPG ICE vehicle on land 10,000 miles emits about 3 mt

• Flying coach nonstop from New York to Los Angeles spews 1 mt into the air

My conclusion from all this number crunching is that I shouldn’t feel too badly about Daystar’s diesel emissions. The fact that our family and friends get to enjoy mostly fossil-free recreation outdoors helps us appreciate time together in a spectacular place without having to travel far.

Traffic on the river [PHOTO] @colinbphoto

However, as we tucked our sailboat into the marina fuel dock between two fossil-guzzling powerboats, I still had an uncomfortable feeling as I watched (and smelled) another 20 gallons of diesel pour into our tank.

The stink took me back to driving across the flaming hellscape of the Permian Basin in far west Texas one night in January 2021. For miles, the air reeked of hydrocarbons as flares lit up the sky, while the only other vehicles on the impeccably maintained asphalt roads were tanker trucks barreling along at ridiculous speeds with their loads of climate-destroying fluids.

And here I was, on a gorgeous mid-May afternoon, dispensing more of the same into my recreational vessel. Just for fun.

Daystar under solar power [PHOTO] @dave keats

Other than not doing something I love doing, what’s the alternative? I’ve considered electrifying Daystar’s propulsion from the moment we bought her. However, between the electric motor, batteries, wiring and labor, ripping out the diesel is a very expensive proposition. And unfortunately, the current range limitations don’t make sense for a relatively heavy cruising sailboat without adding significant solar charging or other power sources to recharge the batteries. On the other hand, going electric for a daysailer docked at a slip with electricity would be a no-brainer once you get over the initial cost. Or build the boat with an electric auxiliary from the beginning, which several makers are starting to do.

Which brings me full circle to the topic of this newsletter: What is the environmental impact of recreational boating, and more importantly, how can we reduce it? A global marine trade association with the ridiculously long acronym ICOMIA recently published a life cycle study comparing several means of marine propulsion. Frankly, I was disappointed to read that battery electric propulsion wasn’t the green panacea I’d hoped it would be.

The short answer is, given the relatively low usage of most sailboat engines, the lifecycle impact of making and replacing the batteries wouldn’t offset the emissions of burning a relatively small amount of diesel over that time. In fact, using a bio-diesel alternative came out the winner in this study over using batteries or traditional marine fuels.

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NOTE: This is a different result than substituting EVs for road transport given their relatively higher usage. (see the bullets above for only 10K miles of a relatively efficient ICE vehicle!). Once again I will remind my readers that EVs are a lower carbon form of mobility than comparable ICE vehicles, but don’t just take my word for it.

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So what should we do? You may be shocked to hear I’ve decided to keep sailing. It helps maintain my sanity in insane times. It gives me another angle from which to appreciate our amazing city on the lake. It reminds me how important a healthy marine ecosystem is to our planet.

All boaters should be especially aware of their role in protecting this fragile and critical element of the biosphere we all inhabit. So keep boating if you wish, but be a good one.