Are Electric Boats Actually Viable?
Short answer: Yes! – Longer answer:
As with most things ‘it depends’ on your expectations and usage habits. Electric propulsion has made huge leaps recently with the advent of brushless electric motors and Lithium batteries and this along with public awareness is driving a revolution. As more technology is developed for land based systems inventive mariners find uses for it afloat.
As more and more boat manufacturers are offering electric options we decided to do a deep dive to see if it would make sense to develop Electric Aluminum Boat Kits. I was actually skeptical (to put it mildly) but the more I looked at it, the more viable it seemed. But there are a few things to consider when deciding to go electric and some boat types are better suited than others so let’s take a look:
Catamarans seem like the best hullform for a few reasons. First is the obvious: they have a lot more real estate for solar panels and they are much easier to propel through the water. I call it the “canoe effect” whereby a longer narrower waterline is far more easily driven than a wide fat one. (Canoes and kayaks for example). You’ll notice racing canoes are as narrow and long as possible. “But Rick, catamarans are WIDE what are you talking about!” Well the hulls can be quite narrow and when you consider there are two of them to spread the load then even more so. If you imagine both hulls connected end-to-end you’ll have a very long and narrow hull form. A 44 foot Cat with 6 foot wide hulls has similar drag characteristics to a monohulled vessel 88 feet long with a 6 foot beam.
Of course monohulled vessels can be electrified too, so which to choose comes down to usage: If you’re running a canal boat, lake fishing skiff, short-route ferries, or a waterski boat at the cottage, where you can plug it in daily and trips are measured in hours then yes monohulls can make a lot of sense too. If you plan to be away for longer periods of time and doing longer distance cruising, then solar panels make a lot of sense. And that’s where Cats shine (pun intended). Catamarans have a lot more room for solar.
Electric Dinghies make a LOT of sense as well. This summer I’d say 30% of all the dinghies at the dock in my favorite anchorages were electric.
So the first question when considering electric: How will the boat be used?
For pleasure cruising let’s look at our habits: Most of us only want to cruise 6 hours a day or so anyway. We cruise to a local anchorage and drop the hook for a few days and then off to another nearby spot. So a solar cat is a good fit. A comfortable displacement cruise speed of 6-8 knots is easily sustainable on batteries for runs like that. Drop the hook and charge up for the next leg. You can get a lot more range by slowing down too. Most Cats can run continuously on solar panels at 4-5 knots as long as the sun shines. Running continuously by engaging the genset is also an option. A genset is a big part of the picture and it’s a must even if rarely used. With a properly sized generator you can cruise and recharge the batteries at the same time. “But then isn’t it just a power boat”? Well, most owners report that they rarely run the genset and this does give you the flexibility of cruising in harmony with nature using solar to charge, OR if time is critical then you have the genset option as well.
It should be noted that Electric Cats can go fast too. Increase the motor size and you can get planing speeds of 15-20 knots. You’ll only get a few hours at that speed but you can cover a lot of ground in a hour at 20 knots. In many locales you can get to your anchorage quickly and then kick back for a day or two to recharge. The downside to upping the horsepower is exponential cost though: With higher amperage and voltage, heavier wiring, more batteries, bigger motors, shafts & props etc. costs will escalate. But this is true of diesel boats as well.
Cost: An Electric Boat does cost a little more up-front but you only pay once. With diesel you pay every time you hit the fuel dock and that adds up to a lot over time. Most fossil-fuel boats will consume more than the cost of the boat in fuel over their lifetime. With electrics there’s virtually no maintenance compared to diesel motors that need oil changes and have hundreds of moving parts. Electric motors only have one moving part and their bearings are typically rated for 500,000 hours or more. Engineers I’ve talked to say 1 million hours can be expected. The only service they’ll ever require is cleaning the strainers on the cooling loop. (Which you have to do on diesels as well). And swapping out batteries every decade or two.
So, moving forward I plan to put a lot of my efforts into creating a catalog of Electric Boat Kits starting with the Solar Freedom 44 which was commissioned by a Toronto client.
More Electric Boat Articles will follow too, I’m sure!
