Electric outboard for a spindrift?

[Bryan Rolfe]

I've been erring away from going with an electric outboard for our Spindrift 10N, largely because you so desperately depend on your dinghy when you're cruising, especially when things go pear shaped, and small gas outboards (especially 2-strokes) are very reliable, and will give you a lot of range for the fuel they burn (especially 4-strokes). It's also easy to find parts for gas outboards in far away places. 

I saw someone mention that they only need 25% throttle to get to hull speed on their nesting dinghy, and the battery lasts 6-8 hours for them, which is actually pretty good. In my cruising experience, I was not frequently motoring the dinghy around for more than an hour a day. This would mean in normal use, we'd only need to achieve a full charge once a week, so 182 Wh/day of surplus energy would be needed a day, and I think we have that (we have 700-900W of solar, depending on if we're anchored or sailing).  

Does anyone have first hand experience with one of these outboards used on a small wooden dinghy? 

[paul_stewart]

The ePropulsion Spirit 1.0      

  https://messing-about.com/forums/topic/16822-electric-or-gas-motor-for-a-core-sound-17-mark-3/#comment-120317

  https://messing-about.com/forums/topic/16825-core-sound-20-mark-iii-16-dawn-patrol/#comment-120360

  https://messing-about.com/forums/topic/16822-electric-or-gas-motor-for-a-core-sound-17-mark-3/#comment-120313

Wayne on ePropulsion Spirit 1.0 

  https://www.youtube.com/watch?v=fnVhaAesIKs   

  https://www.youtube.com/watch?v=bQrcqvPWU2Y&t=0s

  https://www.youtube.com/watch?v=yTEm-beE6SQ&t=0s

Quentin on ePropulsion  Spirit 1.0

  https://www.youtube.com/watch?v=3d2jzglB4fM&t=0s       

The ePropulsion eLite system   

  https://www.youtube.com/watch?v=z_RqMk-ioas

  https://youtu.be/PGVP8XWCEfQ?t=371  
                                    
                                    
 

[Alan Stewart]

I'd be very tempted to go with an EP Carry motor. It's less powerful but has a number of advantages in this case (small Spindrift dinghy). 

You can take the motor with you pretty easily if you're worried about it being stolen. 
The motor is in the top not the pod so no worry about striking bottom and damaging the seal of the pod. Downside is the motor needs to be protected from rain/salt water. 

The prop is easily replaced and the bevel gear is easily replaced. 

Can use any battery even a very small one just what is needed. No need for proprietary bulky battery. 

I've never had the chance to try one but i think it would be ideal for cruising. Might not quite hit hull speed but other than that. I believe they also came out with a larger version recently. 

[Andy B]

Paul, I can't remember the state of your boat build.  Have you used the Spirit 1.0 for your CS-20.3?  Does it push it along fine?  If it does, it would certainly work for my 20.1, someday.

[paul_stewart]

Andy, we've had it in the water once at the 2024 B&B Mess-about;  it seemed very good to me.  For a more experienced comment,  I suggest this one ....

 

https://messing-about.com/forums/topic/16822-electric-or-gas-motor-for-a-core-sound-17-mark-3/#comment-120313 

 

 

[Bryan Rolfe]

Thanks for all the links to peruse, some of these I've seen, some are new. 

I think my thoughts on the EP Carry are mixed. Didn't Torqeedo go from a gear drive to a direct drive after having many units fail in the field? I feel like a well constructed direct drive might be more reliable. ePropulsion also sells a cord that allows you to plug in an external battery now if the proprietary one fails, or if you just want to use your own. The Newport NT300 is kind of interesting too, but you're not saving a ton of money if you purchase their battery -- perhaps if you build your own or buy a LiTime battery or similar. Having the battery on the floor of a small dinghy is also pretty awkward and almost certainly problematic without a way to encapsulate it. 

Economically the electrics are still pretty expensive, but I do really like the appeal of not having to carry/get gas we otherwise don't need, and being able to quietly explore places. I have really fond memories exploring the mangroves around Panama, and it being kind of a bummer to have that engine puttering the whole time. 

[paul_stewart]

New electrics for 2025 ...

 

[Aphers]

I used a Bison 88lb motor on my S11N, powered by a 60Ah LFP battery. 

 

Pros:

quiet, reliable, instant power including reverse. Happily took the dinghy to 4.5kt. Battery gave an hour of endurance at full power. No fuel smells, costs, spills, or mixing. Relatively cheap to buy.

 

Cons:

Not any faster than sailing, nor much faster than a motivated rower. The cheap non-Bluetooth battery has no way of telling you how charged it is (by the time the voltage starts dropping, it's nearly flat). Build quality on the supposedly saltwater rated Bison was very flimsy compared to any petrol outboard. Lots of plated mild steel components, plastic transom clamps. No easy way to secure the battery against theft.

Biggest problem of all was the connection to the battery. I just had eyes crimped on to the motor cables, and I fixed these to the battery terminals. No weatherproofing of any kind. Inevitably things get splashed or dropped, corrosion sets in, and you start getting hot connections and power loss. I chopped the end of the cable and crimped on a new eye several times.

 

I'm going to resurrect the idea, but I will choose a smaller motor with lower power requirements. That will make it easier to source suitable waterproof connectors. I will mount the battery in a box with a battery monitor, and make sure it has a strong point to lock it to the dinghy.

[Bryan Rolfe]

One thing I considered with options that accept an external battery is to just build a small LFP that I could fit in one of the storage areas under the aft seats, and installing a connector on the side of the seat you could just plug into. The main problem is designing a battery with the available LFP cells that are out there, that could fit through the 8" circular access port. 

The advantages would be: 

• No proprietary battery
• Convenient, safe storage, in a dry location.
• Out of sight from thieves, and probably makes the outboard itself less desirable for thieves.

 

Because most of these outboards run at 36V, you need 12 x 3.2V cells. 

These 25AH cells might work, certainly small enough  I'm not sure if they're grade A though:
https://www.amazon.com/LiFePO4-Phosphate-Rechargeable-Max-Continous-Discharge/dp/B0CQYL9ZW4/ref=asc_df_B0CQYL9ZW4?mcid=4bc96a4516ec3862a29c08d770ca448a&tag=hyprod-20&linkCode=df0&hvadid=720249836134&hvpos=&hvnetw=g&hvrand=5918267030363300650&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9031012&hvtargid=pla-2380154735443&th=1

[Lille Ø]

We tested a Torqeedo Travel XP (their most powerful model) with our Spindrift 9N, and it was definitely too powerful for our needs. But that's what a buddy boat had, so it was an easy thing to try. The dinghy motored quite beautifully as long as we kept it easy on the throttle.

 

I talked with a fellow boater in Bequia with a hard dinghy of a very similar size to ours. They had the ePropulsion eLite and were very happy with it. Interesting recommendation was to motor with the centerboard down in heavier conditions.

 

We have decided to look at one of the smaller integrated electric outboards (ePropulsion eLite, Temo 450, ThrustMe Kicker, etc). While similar performance could be had more cheaply with a trolling motor and a separate battery, I think the ease of use will also be important. The choice of what to buy will likely boil down to what we find here in the Caribbean. In the meanwhile, happily rowing and sailing around.

[Don Silsbe]

You’re gonna laugh at me, but I don’t care.  I’m thrifty and practical.  On my Two Paw 8 nesting pram I use a Minnkota C2 34# thrust trolling motor and an Optima Blue Top AGM battery.  The motor currently costs $150, and the battery $330.  I’ve had my Minnkota for 10 years, and the battery for four.  My wife and I have “motored” through a chain of lakes with this setup.  We were gone about an hour, with no appreciable loss of power.  You can spend nearly ten times that on a slick lithium-powered setup.  If you’re OK with a separate battery, you can check this box for under $500.  If you lived closer, I’d loan you my setup.  See if you can’t borrow one to try out.

Since my pram has a square bow, I hung it off the bow.  I swung the control head around 180 degrees, due to the bow mount orientation.  (This is looking forward.)

 

My bride, my hound, and the battery were in the stern.  (Looking aft.)
 

I was at the helm in the bow.

 

[Aphers]

On 2/20/2025 at 8:55 PM, Don Silsbe said:

 the battery $330.

 

On 2/20/2025 at 8:55 PM, Don Silsbe said:

 

 

That's a lot of money for a battery. My lithium battery was cheaper than that, and gives nearly twice the useable capacity at about half the weight.

[Aphers]

On 2/19/2025 at 6:47 PM, Bryan Rolfe said:

One thing I considered with options that accept an external battery is to just build a small LFP that I could fit in one of the storage areas under the aft seats, and installing a connector on the side of the seat you could just plug into. The main problem is designing a battery with the available LFP cells that are out there, that could fit through the 8" circular access port. 

The advantages would be: 

• No proprietary battery
• Convenient, safe storage, in a dry location.
• Out of sight from thieves, and probably makes the outboard itself less desirable for thieves.

 

Because most of these outboards run at 36V, you need 12 x 3.2V cells. 

These 25AH cells might work, certainly small enough  I'm not sure if they're grade A though:
https://www.amazon.com/LiFePO4-Phosphate-Rechargeable-Max-Continous-Discharge/dp/B0CQYL9ZW4/ref=asc_df_B0CQYL9ZW4?mcid=4bc96a4516ec3862a29c08d770ca448a&tag=hyprod-20&linkCode=df0&hvadid=720249836134&hvpos=&hvnetw=g&hvrand=5918267030363300650&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9031012&hvtargid=pla-2380154735443&th=1

Why not just buy a 12v trolling motor? Then you only need four cells. 

Of course lower voltage means you need to deal with bigger currents, bit on these motors it's never going to be anything massive. Mine was the most powerful 12v available and it drew 53A.

[Bryan Rolfe]

I'm not sure what it is about the trolling motors that doesn't have me sold yet. They just don't seem like they'd hold up to full-time ocean cruising conditions, and it also seems like I'd be operating them at a higher % of their max output to get to our hull speed, and thus we'd have much less range on a full charge. 

But they are much much cheaper. 

That said, I did 3D print the dimensions of one of the 25AH cells I had linked above, and it absolutely would not fit through my 6" hatches if built into a battery pack. Esepcailly not one built of 16* cells. I realized the ePropulsion batteries are 48V. 

[Aphers]

I'm sure you get what you pay for. 

Build quality was my main concern about the trolling motor I had. Perhaps if you ring it off in fresh water after every use it would be ok. If and when I try this again, I'll be looking over the new motor carefully and where possible upgrading all the plated mild steel components for stainless. 

 

I paid £100 for the motor (secondhand but unused- I think they are more like double that new) and £260 for the battery (in 2020... lithium battery prices have fallen swiftly since then).

So overall far cheaper than a Torqueedo or ePropulsion, and the little battery has been useful for other things too.

 

A friend has put together a similar system but with a bit more thought and effort. He has the battery in a watertight box with good quality connectors and a Bluetooth battery monitor, so that he can check his much charge is left. Added to the cost but it has made it useful enough that he no longer uses his petrol outboard. 

 

By the way it's pretty easy to cut down the shaft on a trolling motor, on mine it was just fibreglass.

[Don Silsbe]

I’ve watched a few YouTube videos on the subject of cheap lithium batteries.  A man with experience in that technology tears apart five cheap ones.  What he finds is very interesting.

 

 

[Aphers]

12 hours ago, Don Silsbe said:

I’ve watched a few YouTube videos on the subject of cheap lithium batteries.  A man with experience in that technology tears apart five cheap ones.  What he finds is very interesting.

 

 

Will Prowse is an excellent resource and has helped countless people, myself included.

There is definitely a lot of junk out there, I wouldn't buy any sort of lithium battery without doing thorough research first. 

Building your own from cells is the cheapest and most reliable route. I've done it twice now. It's not rocket science and anybody who is capable of building a boat is likely practical minded enough to take on such a project.

[Aphers]

12 hours ago, Don Silsbe said:

I’ve watched a few YouTube videos on the subject of cheap lithium batteries.  A man with experience in that technology tears apart five cheap ones.  What he finds is very interesting.

 

 

Will Prowse is an excellent resource and has helped countless people, myself included.

There is definitely a lot of junk out there, I wouldn't buy any sort of lithium battery without doing thorough research first. 

Building your own from cells is the cheapest and most reliable route. I've done it twice now. It's not rocket science and anybody who is capable of building a boat is likely practical minded enough to take on such a project.

[Captain Tim]

After seeing what goes on inside one of those lithium batteries, I'm happy I went the 2.5 hp Suzuki route.

29lbs plus 8lbs for extra gallon of gas. As a side note, I buy my gas at the local airport which is ethanol free. I think this is a huge reason the little Suzuki starts and run so well. 

 

[Don Silsbe]

@Captain Tim— I only use ethanol-free gasoline in all my small motors.  My Suzuki 2.5 has nearly an unlimited range, if I pack only 2 gallons of fuel on board.  Considering my initial outlay for the motor was under $900, I think I did the right thing, too.