Electric Sailboat Drives

[jviss]

A guy in my harbor just got a brand-new Marshall Sanderling 18' Catboat. The are made in South Dartmough, i.e., Padanaram, just down the street from me. They list about $48K plus $13.5K for electric drive. I am told with the options he got he spent upwards of $70K total.

Anyway, he's on a mooring. In the afternoon he brings it to the fuel dock, after the fuel dock is closed, to charge it up, then puts it back on the mooring. Fine.

My observation is that this is cool, but it doesn't scale. What happens when lots of such boats populate harbors? Maybe someday they will have "electric moorings" for these guys.

 

[dlochner]

My observation is that this is cool, but it doesn't scale. What happens when lots of such boats populate harbors? Maybe someday they will have "electric moorings" for these guys.

They will sprout solar panels.

 

[jviss]

They will sprout solar panels.

I thought that, but I don't think you could deploy enough solar on a boat that size to go sailing every day. Maybe once a week?

 

[jviss]

I'm waiting to see some dude with a portable Honda generator charging up his electric drive daysailer.

 

[kloudie1]

Shocking observation!
Maybe something like the pump out boats? A big diesel generator on a little barge to make the rounds and charge 'em up?
Quite a cost to signal how "green" a person is.
Makes sense if ya only use it a little to get on and off the mooring.. An 18 foot boat is not doing any serious distance sailing.

 

[jviss]

Shocking observation!
Maybe something like the pump out boats? A big diesel generator on a little barge to make the rounds and charge 'em up?
Quite a cost to signal how "green" a person is.
Makes sense if ya only use it a little to get on and off the mooring.. An 18 foot boat is not doing any serious distance sailing.

Well, these catboats are quite roomy, you could cruise around our area in one. Plus, it's quite a ways from his mooring to the mouth of the harbor, maybe a mile and a half? Plus, the current can be significant, up to 3 kt. when ebbing.

 

[LloydB]

Tesla was right in the first place, we don't have room for tethered electricity it must be broadcast wirelessly and stored in the cloud.

 

[dlochner]

Tesla was right in the first place, we don't have room for tethered electricity it must be broadcast wirelessly and stored in the cloud.

There's a name for that, it's called lightning.

 

[Will Gilmore]

Perhaps fuel docks will learn to service electric, just as they do diesel and gasoline. Wouldn't want to miss out on a potential money making opportunity. Maybe marine Tesla charging stations at the dinghy dock.

I like the idea of electrified moorings. That would be much more doable than piping fuel to a mooring. Solar is getting more efficient and so is wind. I can also picture a wave generator that works like those old self-winding watches. For every boat wake that passes by, there's another few micro volts added back into your battery bank.

-Will

 

[BarryL]

Hey,

If you don't have lots of solar I don't think a mooring makes sense for electric engines. Maybe some combination of solar, wind generator and water generator (when sailing in a decent breeze) would be sufficient to recharge the battery bank.

Barry

 

[rgranger]

My observation is that this is cool, but it doesn't scale. What happens when lots of such boats populate harbors? Maybe someday they will have "electric moorings" for these guys.

You are right! It won't scale.

I’ve been thinking about electric propulsion for a long time now. I’m of the opinion that if we really want this to work, congress (or the industry) will need to standardize the batteries. Then instead of pulling your boat (or car) up to a charging station to recharge your battery, you pull up and swap out your battery. The more I think about this, the more I’m convinced it is the only way to make electric propulsion scale in the short term. It would also incentivize the owners of the current infrastructure (gas stations) to get in the game instead of opposing it. It would be a win-win. We could have the range issue for electric cars solved now if we had battery swaping stations. I think the same could be said for electric marine propulsion.

 

[jviss]

We could have the range issue for electric cars solved now if we had battery swaping stations.

I think of winters in New England, lots of muddy and salty ice and slush on the bottom of the car, and so on. Tough to do a "hygenic" battery swap in those conditions.

I think the same could be said for electric marine propulsion.

Whoa, kinda tough to quickly, easily, and economically lift the batts out of a boat!

We need some kind of new discovery or invention, like liquid Coulombs, or something. Maybe gasoline or diesel fuel?

 

[jviss]

Solar is getting more efficient and so is wind.

Even at 100% efficiency, how many square feet (square yards, acres, etc.)) of photovoltaic cells would you need to put a days worth of motor use back in - overnight?

 

[rgranger]

We need some kind of new discovery or invention, like liquid Coulombs, or something. Maybe gasoline or diesel fuel?

LoL...

I heard about these new engines that can use steam to drive a motor.... even crazier I've seen people power a boat using wind.

 

[rgranger]

I think of winters in New England, lots of muddy and salty ice and slush on the bottom of the car, and so on.

Yeah... I used to live in Minneapolis. It is still a mystery to me why anyone lives there.

Nine months of winter and three months of road construction.

 

[High Current]

I think it depends at least a little on your priorities as a sailor. I electrified my old Hunter 25, and on a tight budget too, and never once used shore power. I built a Bimini with 400W of solar on the stern and that could get me about 1.5kWh of energy on an average day in Maine - enough to motor for about an hour at 3.5 kt. My bank of lead-acid batteries stored approximately 6kWh of usable power. As primarily a weekend cruiser it was more than enough so I put in an induction cooktop too!

But there were real limitations and compromises. I primarily sailed my boat, with the motor mostly for getting on and off the mooring, getting myself out of trouble, or occasionally powering through a dead calm. That meant my speed was largely a function of the wind or, if I had to motor for an extended period, was kept low-ish (3kt) to maximize range. Although I successfully took a couple of longer (4-5 day) cruises and was able to keep the battery near full the whole time, I certainly didn't have the same "damn the wind" freedom of many cruisers and I observe a fair number who seem - for whatever the circumstance - to prefer to motor even on a glorious day with the wind at their backs. Electric certainly wouldn't be right for them.

Now I have a C34 with a diesel and if I'm honest it is a bit liberating to be able to start the engine and cruise at 4 kt any time the wind dies, or linger a bit longer somewhere knowing I can make it home by a specific time. But man do I miss that quiet, smooth, instant-on, reliable, odorless, effortless, low-maintenance electric. Next up: a hybrid...stay tuned...

 

[jviss]

I think it depends at least a little on your priorities as a sailor. I electrified my old Hunter 25, and on a tight budget too, and never once used shore power. I built a Bimini with 400W of solar on the stern and that could get me about 1.5kWh of energy on an average day in Maine - enough to motor for about an hour at 3.5 kt. My bank of lead-acid batteries stored approximately 6kWh of usable power. As primarily a weekend cruiser it was more than enough so I put in an induction cooktop too!

But there were real limitations and compromises. I primarily sailed my boat, with the motor mostly for getting on and off the mooring, getting myself out of trouble, or occasionally powering through a dead calm. That meant my speed was largely a function of the wind or, if I had to motor for an extended period, was kept low-ish (3kt) to maximize range. Although I successfully took a couple of longer (4-5 day) cruises and was able to keep the battery near full the whole time, I certainly didn't have the same "damn the wind" freedom of many cruisers and I observe a fair number who seem - for whatever the circumstance - to prefer to motor even on a glorious day with the wind at their backs. Electric certainly wouldn't be right for them.

Now I have a C34 with a diesel and if I'm honest it is a bit liberating to be able to start the engine and cruise at 4 kt any time the wind dies, or linger a bit longer somewhere knowing I can make it home by a specific time. But man do I miss that quiet, smooth, instant-on, reliable, odorless, effortless, low-maintenance electric. Next up: a hybrid...stay tuned...

Very nice post, thanks.

I built a Bimini with 400W of solar on the stern

Wow, that's a ton of solar on a boat that size! How many square feet, do you think?

 

[jviss]

Next up: a hybrid...stay tuned...

I like the idea of a hybrid. I'm interested to hear your approach to this. I know Vetus made one, I don't think they do any longer.

My boat is such that putting enough battery on it for that is not practical, unfortunately. It would be cool to have a sailboat specifically designed for hybrid propulsion, with a huge, low-down battery bank.

 

[High Current]

You are right! It won't scale.

I’ve been thinking about electric propulsion for a long time now. I’m of the opinion that if we really want this to work, congress (or the industry) will need to standardize the batteries. Then instead of pulling your boat (or car) up to a charging station to recharge your battery, you pull up and swap out your battery. The more I think about this, the more I’m convinced it is the only way to make electric propulsion scale in the short term. It would also incentivize the owners of the current infrastructure (gas stations) to get in the game instead of opposing it. It would be a win-win. We could have the range issue for electric cars solved now if we had battery swaping stations. I think the same could be said for electric marine propulsion.

Battery swap stations were going to be the future when I bought my Tesla 10 years ago but I think the cost, logistics, and improving technology buried the idea. Batteries are getting cheaper and they're charging faster. Range issues are already the exception, not the rule, for modern EV's - assuming you have a place to plug in at home (which is a very big IF). How many days do you actually drive more than 200 miles? And how many trips to the gas station do you have to make to offset the 1/2 hour spent at a fast charger every now and then on a long trip?

Even at the docks, it would be so much easier to build a quick-charger than a battery swapper (presumably with cranes and robots?). Besides, as great as electric drives can be for us sailors who use our engines as auxiliaries and generally run them below hull speed, batteries just don't have the energy density to realistically power speed boats and semi-displacement hulls in any way that remotely resembles cost-effectiveness. It takes significantly more energy to power a motor boat for an hour than a car, and weight has a much more direct impact on power use (in a car, it mostly affects acceleration, not cruising).

So the target audience would be small and - if you see my above post - a modest solar array would eliminate the need to use the docks at all for most sailors so crowding would be minimal and anxieties about availability could probably be managed by a reservation system.

 

[stickinthemud57]

My neighbor at the marina has a Colgate 26 with an electric kicker. It has a removable battery, so he just takes it home and keeps it charged there. I still have my dirty little 8 horse Tohatsu 2-stroke, and 3 gallons of gas typically lasts me most of the sailing season. I would love to get rid of the noise and the smell, but not having to worry about having enough juice (and the cost of the electric kickers) makes me stick with my Tohatsu.