Dingy Motor

[hgd]

I don't know how you feel, but I have had it with the present state of technology supporting the design of small the internal combution gasoline engines. They are extremely unreliable, never start when you need them, they are now so heavy it is almost impossible to drag them to a shop. I decided to go electric, there have been significant improvements in the technology which have made it a viable alternate to the gasoline engine. I bought an Epropulsion engine from Emarine in Ft. Lauderdale. I have cruised with it quite successfully for a year. Recently I noticed a reduction in battery life which did not seem to be what I expected . Since it had a 2 yr warrantee I took it back to Emarine (as a passing notice the manufacture's rep for Epropulsion it the ex owner of Emarine and has an office on the premises). They found the charger and the Li batteries to be ok but there is a circuit board in the battery that assures the safe operation of the Li battery as suspect. They, in a timely manner, replaced the battery with a new battery. This unusual act of responiblity today salvaged my cruise!! Emarine and Epropulsion deserves recognition!!

 

[psneeld]

Funny...both my little portable gensets and 9.9 hp outboard would start first or second pull.

Zero maintenance on the genny for the last 10 years.... annual fluids and one water impeller in the last 10 years on the Yamaha four stroke.

Equivalent E outboard would cost multiple times the gasser price. With not much history on how long the battery will last with a $3000 replacement.

I am looking forward to the E-outboards of the future....but for now...unless it's just a little one.... not on my skiffs.

 

[Jarrow Lily]

Our current boat came with a 4HP four stroke Suzuki, made in 2007. So, now 15 years old.


Two seasons ago I replaced the impeller, kept the old one - which was perfect - as a spare.


I have just serviced it ready for this years cruise. The fuel tap was removed as it had become very stiff. The plastic swiveling piece removed and cleaned - powdery deposits were causing the stiffness - and the 'O' rings greased with rubber grease. All good now.


It ALWAYS starts readily. This is because I allow the engine to run with the fuel off before taking it out of use, even for a few days. This stops the modern fuel going off in the float bowl. Pulling the starter cord half a dozen times with the fuel tap on soon refills the float bowl via the manifold suction. Then choke out, first pull.


It uses about a litre an hour pushing a 2.4 inflatable along. I made a simple crane to lift it on and off the storage bracket with a 3:1 hoist.


If we had an electric outboard our regular trips exploring would not happen. Our friends have one and dont trust it for more than half an hour.


I also have a Johnson 4HP two stroke twin. 25 years old, starts and runs perfectly.


It requires premix fuel-oil, uses far more fuel but is exceptionally light - 15 kilos.


I am a retired specialist small engine mechanic, I rarely find an engine I cant get working OK.


IMHO, electric outboards are nearly there, but not quite.

 

[NEtrawler58]

I don't know how you feel, but I have had it with the present state of technology supporting the design of small the internal combution gasoline engines. They are extremely unreliable, never start when you need them, they are now so heavy it is almost impossible to drag them to a shop. I decided to go electric, there have been significant improvements in the technology which have made it a viable alternate to the gasoline engine. I bought an Epropulsion engine from Emarine in Ft. Lauderdale. I have cruised with it quite successfully for a year. Recently I noticed a reduction in battery life which did not seem to be what I expected . Since it had a 2 yr warrantee I took it back to Emarine (as a passing notice the manufacture's rep for Epropulsion it the ex owner of Emarine and has an office on the premises). They found the charger and the Li batteries to be ok but there is a circuit board in the battery that assures the safe operation of the Li battery as suspect. They, in a timely manner, replaced the battery with a new battery. This unusual act of responiblity today salvaged my cruise!! Emarine and Epropulsion deserves recognition!!

I bought an eProp electric a couple years ago for the same reasons you cite. I had a new 3.5hp 4 cycle Merc that was a pain. Electrics are making great strides and I agree that they are not quite ready for prime time once you get above a few HP. But for the 2-4 HP range, electrics clearly have the advantage in my mind being perfectly reliable while weighing less, among other pros. I would probably still be using gas if the new small engines weren't so terrible.

 

[O C Diver]

I have an Epropulsion 3 HP unit. Pushing my Trinka 10 in displacement mode, it has a range of over 20 miles. If one needs more, a second battery pack (around $1,000 when I purchased my outboard), it's range would be 40 miles, no different than carrying a second fuel tank. 16 miles has been my longest day trip so far.

Being easily separated into two equal weight parts, there is no need to crane the outboard onto the boat.

In displacement mode, the electric outboard is the clear winner as far as noise, smell, convenience (store in any position without leaking or waiting for crankcase oil to settle back), safety (no gasoline on the boat), and maintenance. In displacement mode, the gasoline outboard is a rotary telephone compared to push button. Yes it still works, but no reason to buy a new one.

Ted

 

[DavidM]

How do the above owners of electric outboards recharge their batteries. That is the biggest downside for me. I cruise in seasons and at places where I don't have to use air conditioning. Seems like recharging would add significant generator run time. Solar covers living needs but not battery recharging demand.

David

 

[rslifkin]

I think at least one of the manufacturers offers a setup to recharge the battery directly from a small solar setup. So if you've got davits, you could mount an extra panel on top of them dedicated to dinghy charging (if you don't have enough surplus solar on board to handle it). Or if you're generator dependent for cooking, let the battery gain some juice during existing generator runs.

If you've got an inverter, you could also recharge that way while moving the big boat. Power draw for the charger shouldn't be all that high, so running it from alternator/inverter shouldn't be much of a challenge.


Personally, I'm not ready to go electric yet. I'd love to, but the prices are still a bit more than I can stomach for something that can only go slow. When they get to the point where planing a dinghy with one is a viable option and/or the prices start to come down more and range gets better, I'll be very interested.

 

[NEtrawler58]

How do the above owners of electric outboards recharge their batteries. That is the biggest downside for me. I cruise in seasons and at places where I don't have to use air conditioning. Seems like recharging would add significant generator run time. Solar covers living needs but not battery recharging demand.

David

When I am away from the dock at anchor, my dinghy use is short trips to shore and back so usually don't worry about charging for several days. Think about how many trips you need to make to use up a 20+ mi range. However, even though I don't use AC at anchor, I do run the generator to top off the house batteries and to use the electric stove and microwave. During those times, it's easy to charge the outboard if needed. You can bring just the battery onboard or run an extension cord and charger out to the dinghy. EProp also sells solar panels for recharge that can even be used while running the motor, but I haven't found the need to buy them.

 

[O C Diver]

Last summer was my first cruising season with the electric outboard. I expected to charge it at least once a week. With the exception or long exploration trips, it was charged about every 2 weeks.

Mine has a 120 VAC charger that I run off the inverter when motoring. Charging off the inverter at anchor is noticeable but not painful. While the 12 volt charger may have been more efficient, I can see a time where I have the Trinka on a trailer, boating more on lakes and rivers.

Ted

 

[Bmarler]

i have a torqeedo and a spare battery that i haven't really needed. i use each battery every other time though so they age together.
i find the 120 volt charger to be slow. you aren't going to top it off with an hour of generator time. so the inverter takes up the slack. i'm at a dock often enough to use shore power to top it off though, so it's not a big issue.
i think if i was going cruising and planning to be without shore power for extended lengths of time i'd get the little solar panel setup that torqeedo recommends. the upside to that is that it can also charge as you are using the motor. i thought i would have range anxiety with it, (hence the spare battery) but it's really a non issue. it goes much further than i thought it would.

i went electric as i was simply tired of carrying gas jugs. then being sure to use all the gas before it goes bad. also tired of maintaining yet another engine. these little electrics have zero maintenance. zero is a good number.

 

[HeadedToTexas]

I am less reliable at remembering the key than my 15 hp Yamaha is at starting on the first or second pull. No complaints, but it is run at displacement speed 90% of the time. Compelling arguments for electric when running at low speed.

In time, I see running our Highfield CL310 on plane a lot more of the time as cruising takes to more explorable places. That plan has always revolved around adding a more conventional helm station, be it Highfield's frame solution or a custom "center console." Perhaps that's what keeps my faith high in gas outboards?

 

[Gotwex]

HGD, thanks for this post regarding the EPropulsion warranty. I just bought one for our Bote SUP. Good to know.

 

[psneeld]

Without describing hp (or equivalent that many don't believe the typical conversion) and boat type and speed desired/attained....

comparing electric to gas is still mostly an exercise in what one wants....not what is "better", "more practical"...etc...etc..

I think most will agree that for small motors and small, slow vessels...hard to beat electric. I agree. But start going up in power needs and those comparisons start to have more cons than pros... Going down and electric starts to get the nod.

So for those considering...make sure you know what you want in performance and then which is more "convenient" or "cost effective."

 

[O C Diver]

Without describing hp (or equivalent that many don't believe the typical conversion) and boat type and speed desired/attained....

comparing electric to gas is still mostly an exercise in what one wants....not what is "better", "more practical"...etc...etc..

I think most will agree that for small motors and small, slow vessels...hard to beat electric. I agree. But start going up in power needs and those comparisons start to have more cons than pros... Going down and electric starts to get the nod.

So for those considering...make sure you know what you want in performance and then which is more "convenient" or "cost effective."

When going from efficient displacement to planing speed, HP needs grow exponentially. Per cubic foot, the amount of energy in a battery won't come close to the same volume of fossil fuel. You're not going to see battery powered airplanes crossing the Atlantic anytime soon.

Ted

 

[Group9]

We have a twenty four year old Nissan 9.8 2 stroke. Always starts on the first or second pull. Last year the carb started leaking gas. I bought a new one for $60 on the internet. My brother in law and I put it on, and it cranked on the first pull after putting the new carb on.

I told my BIL, that I was glad he was there to see that, as otherwise I didn’t think anyone would believe it!

 

[psneeld]

When going from efficient displacement to planing speed, HP needs grow exponentially. Per cubic foot, the amount of energy in a battery won't come close to the same volume of fossil fuel. You're not going to see battery powered airplanes crossing the Atlantic anytime soon.

Ted

Don't disagree because have been researching like crazy going from a 40 foot trawler to a 12 -14 foot jon boat. The electrical advantage would be huge...but I can get an electric start 9.9 gasser, big dual purpose battery and an electric trolling motor plus a fishfinder hookup to the battery for still way less than an equivalent electric with the desired endurance.,,,and possibly little in weight savings at 9.9 hp and above.

If I just want to putt around the harbor, sure electric will get me a mile or so round robin but pretty slow.... but accepting a weight penalty...a conventional battery and electric trolling motor will get me similar performance with older tech and still a fraction of the price.

So again I caution those debating the decision to be sure they have the right speed and boat type in mind before listening to posts that discuss satisfaction without parameters.

No different than most topics I chime in on.

 

[O C Diver]

We have a twenty four year old Nissan 9.8 2 stroke. Always starts on the first or second pull. Last year the carb started leaking gas. I bought a new one for $60 on the internet. My brother in law and I put it on, and it cranked on the first pull after putting the new carb on.

I told my BIL, that I was glad he was there to see that, as otherwise I didn’t think anyone would believe it!

Actually I find it harder to believe you could find a new carburetor for a 24 year old anything.

Ted

 

[psneeld]

I just waited 3.5 months for a fender and hood for a 2019 Ford E-350.

Would have been better off ordering for a Model T.

 

[kthoennes]

We have a 4hp Yamaha 2-stroke on our dinghy, vintage 1987. I continue to be surprised how easy and relatively quick it is to get parts, even now. Just ordered a new throttle cable because the old one had gotten all frazzled on the end and wouldn't easily fit through the setscrew hole anymore. The cable has to be removed for easy access on a proper carb cleaning. Ease of ordering parts, even now, makes me think there are still lots of them in current use. Heck I can even still get the "Yamaha 4HP" sticker for the cowling, if I were that particular. Those are excellent indicators of long term reliability right there.

 

[NEtrawler58]

So a little perspective. In my experience, older 2 strokes are much less problematic than newer 4 strokes in the small HP range. New 2 strokes are no longer available for purchase in the US. To keep the comparisons more realistic, if you had to go out today and buy a new outboard, 4 stroke is all you can buy. As I said earlier, if you only need 2-4 HP, electric makes a lot of sense even at about twice the cost. If you want to go fast and need more HP, I think gas is still good option. At 10 HP or more, you're not dealing with lifting the motor by hand anyway. Also the bigger motors have less carb problems. Regarding having a center console dinghy, Eprop has a helm for their motor that will allow wireless connection for throttle and steering. But if you have that dinghy, you probably want more HP anyway.

 

[Lollygag1]

Have a Yamaha 2.5 starts right up, pushes our 9.5’ rigid inflatable w 4 adults along just fine. May not go super fast but works fine for exploring and getting dog to shore. Prime reason to buy was the low weight which makes it easy to get on and off.

Use an electric trolling motor on the fishing kayak. Can run about 90min on a charge.

 

[Slowmo]

I disagree with HGD who claimed that the IC engines ".. are extremely unreliable, never start when you need them, they are now so heavy it is almost impossible to drag them to a shop". Modern IC outboards are extremely reliable, as evidenced by their extensive use in commercial applications. In the past 30 years I've never had a no-start on my outboard, never. I agree that weight is an issue with 4-cycle OB's but this has improved with newer designs. However you must also consider battery weight with an electric. Most electrics are very low power (1-3HP). These get by with a good sized deep cycle battery (if you can recharge regularly). Speeds are quite limited with this power level. If you are absolutely sure your use is limited to sheltered harbors and short distances that may be fine. However if you cover larger distances, need more speed, or depend on the dingy as a lifeboat then electrics become quite problematic.

The primary issue with an electric outboard isn't the electric outboard itself, they're quite simple. The problem lies in energy storage. Batteries have a very low power density compared to gasoline (or any HC fuel). To put it in terms of electricity a gallon of gasoline has roughly 33 KWh. A really good deep cycle battery may have 125Ahx12V=1.5KWh. Thus the problem is obvious. In order to provide more than nominal power to the outboard the battery requirements quickly become impossible for a dingy. Even the equivalent of a single gallon of gas would weigh hundreds of pounds. As I said if you are 100% sure that the only conceivable use of dingy is short distances in relatively serene conditions then they're a convenient choice. However if you expect to cover more than a nominal distance, encounter adverse conditions, or possibly consider the dingy as a lifeboat, electric outboards quickly become uncompetitive.

 

[Group9]

Actually I find it harder to believe you could find a new carburetor for a 24 year old anything.

Ted

I think you can find a square basketball on the internet if you look hard enough. ?

 

[JustCruisin]

I have been following this with great interest ...as I am new to the trawler experience. As a newbie I thought that most of what I will be doing is going from an anchor point to shore and some short putting around on the Chesapeake Bay. So I now have a 10 ft. RIB with a 55lb thrust trolling motor and a 100 ah lifepo4 battery in a Newport box. It should run over two hours wide open. Have a charger for it I can run off inverter or genny/shore power. The whole setup was less than a torqueedo...if it is not enough I will buy a little gasser. We'll see how it works soon. I am looking forward to warmer weather soon...

 

[NEtrawler58]

A few things in this thread are true, some half-truths, and some that are false. I'll try to summarize without going into all the pros and cons of gas vs. electric because that's been covered extensively in other threads.


New electric outboards are not the same as electric trolling motors that have been around forever. They are more powerful, have modern electronic displays and controls, have a LiPo battery not a deep cycle. They will run for hours with considerable range at less than full throttle. Weight - 4 stroke outboards are much heavier than 2 strokes which are no longer available for purchase new. The electrics have 2 main components, battery and motor, each of which weigh about 20 lbs which is less than the smallest of gas motors. The very small 2.5 hp gas motors are air-cooled and very loud, the electrics are silent. Larger gas motors are very reliable and still the best choice for faster speeds and longer range if that's what you need.

 

[ancora]

We bought a Torquedo last year and are quite pleased with it. For me, it is a lot easier to get it down from the sundeck to the swim step and the Admiral loves just pushing a button to run it. The only sound is the water flowing past the dinghy.

 

[Hippocampus]

Used gas in our daily driver. If you use your dinghy to explore, go through surf, carry multiple people or stores any kind of distance, use it intermittently through out the day none of the current available e engines have sufficient hp or range. Have multiple friends who outfitted with e engines only to return to gas. The e is fine if your requirement involves just getting out to a mooring. But for any kind of extended use or heavy duty use they’re just not there. Wasn’t uncommon to put the thing on plane for hours over the course of a day. Even when in the northeast would spend a whole day either fishing off the dinghy or exploring. In the Caribbean getting on/off a beach with a big surf you need the hp.
Being in the Caribbean for most of 8 years the dinghy engine saw a lot of use. 2 strokes were available down there. . Ours had a great hole shot and was light but used a lot of fuel. Switched to a Suzuki 20hp injected 4 stroke which slipped gas in comparison. For me biggest deal is putting a really good filtering system between the fuel tank and the engine. Like diesels think most troubles with small gas dinghy engines is bad fuel not bad engines.
Our current dinghy has a 40hp on the back. With 4 rod holders, no fabric and large load carrying better and less expensive to use the dinghy rather than the boat when settled in an area.
Think long and hard about what’s the longest range you will require. What’s the greatest load. What speed do you what to travel at. After you answer those questions your choice is made for you. I like e engines. On the square back canoe I fish electric is so much better than gas but cruising unfortunately gas will continue to be the best option for many.

 

[Slowmo]

A few things in this thread are true, some half-truths, and some that are false. I'll try to summarize without going into all the pros and cons of gas vs. electric because that's been covered extensively in other threads.


New electric outboards are not the same as electric trolling motors that have been around forever. They are more powerful, have modern electronic displays and controls, have a LiPo battery not a deep cycle. They will run for hours with considerable range at less than full throttle. Weight - 4 stroke outboards are much heavier than 2 strokes which are no longer available for purchase new. The electrics have 2 main components, battery and motor, each of which weigh about 20 lbs which is less than the smallest of gas motors. The very small 2.5 hp gas motors are air-cooled and very loud, the electrics are silent. Larger gas motors are very reliable and still the best choice for faster speeds and longer range if that's what you need.

Its probably best to make sure we understand the physics behind this comparison This gets the comparison away from opinion and anecdote and onto a solid technical footing. From a mechanical engineering POV (which is my training) the comparison is pretty simple. It is based on energy storage capacity and the efficiency of energy conversion to motive power. These factors dictate how much power you can extract and thus dictate speed and range.

The difference between an electric and IC outboard is primarily a difference in how the energy is stored and then converted to propulsion. An electric motor is more efficient at energy conversion, about 90%, than an IC engine at 20-35% (I use 25% in calculations). An Otto cycle engine will vary efficiency depending on load, they're most efficient at full power. An electric doesn't care much.

However this is only half the story, the other half is energy storage. In this batteries suffer. The best current batteries, Li-Ion, have 50-250Wh/kg of energy density with 100Wh/kg appearing to be typical of what's on the market (higher density get into cooling requirements). This looks good compared to lead acid which are 30-50kWh/kg. However, gasoline is the equivalent of 9444 Wh/kg. There is an additional confounding since you can't pull all the energy out of a battery as you can with a liquid fuel. So using round numbers you need about 250lb of battery for each equivalent gallon of gasoline (depending on how far down you can pull the battery this could increase a bit, if batteries improve some it goes down a bit)

The comparison that drives range and speed is the available energy times the efficiency of energy conversion. Based on this gasoline provides 10-25 times more available propulsion energy per unit weight of energy storage than state of the art batteries, even with the lower efficiency of the IC engine. The higher number is actually more realistic today without cooled batteries.

None of this is intended to dismiss E-outboards out of hand but to allow one to make a comparison on an equivalent basis. Based on the physics it is impossible to say an e-outboard is equivalent to an IC outboard overall. The limitation on going up on power for a e-outboard is fundamentally the battery weight. The equivalent of a 6 gallon tank of gas that is 50lb becomes about 450lb (compensating for energy conversion efficiency of the motors otherwise you're at 1500lb). Hence the tendency for e-outboards to be lower power since then you can keep the battery weight compatible with the capacity of the dingy and the ability to bring the battery aboard the main vessel for charging. Obviously this comparison will continue to improve as battery technology evolves with solid state being the next horizon, we'll have to see what that brings us.

 

[BruceK]

We are happy with one of the last Merc/Tohatsu 3.3 2 strokes. Pros: really light,water cooled, starts easily. Cons: no reverse gear just Fwd and N, and it hates stale fuel.

 

[NEtrawler58]

We are happy with one of the last Merc/Tohatsu 3.3 2 strokes. Pros: really light,water cooled, starts easily. Cons: no reverse gear just Fwd and N, and it hates stale fuel.

I agree. If I could have bought a 2-stroke a couple years ago, I probably would not have electric now. Although the fwd/rev on electric is very convenient. No spinning the motor and not even a gear shift, just twist throttle one way then the other with stop in the center.

Hippo you are absolutely right, for the 20-40 hp use case you describe, there is currently no good electric alternative. But it's kind of like comparing a bicycle to a motorcycle. Each has a different purpose and is great for what it is supposed to be used for.

Slomo, thanks for the science and I won't dispute any of it. I'm an engineer and appreciate scientific data. However, the thread is not about gas vs. electric energy storage, it's a dinghy motor selection. I still contend if your use case is for a 2-4 hp motor, electric has many advantages over gas. An interesting thought about your data is, I've never seen the same comparison done with cars though I'm sure it has been. Doing a VERY quick search on Teslas, I find that their batteries weigh somewhere in the range of 900-1200 pounds and the overall weight of the car is relatively similar to a gas powered car, yet the Tesla is much faster and has similar or greater range. I don't want to divert this thread into electric cars, my point is you have to look at the intended use. If an electric fits that, it's not really important how much energy is contained in a can of gas.