Electric Inboards

I know this electric/solar subject has been beat to death. Recently have become extremely curious about the subject. Considering gas is 4 bucks a gallon on land and fetches 5 in water. Anyways i seen on west marine electric inboards capable of pushing 5 thousand pounds. So if you ran 2 it would be around 10k. I know installed they run about 20k giver er take. To me though if someone is spending 10-15 k a yr on fuel......Everybody dismisses bc of battery weight, charging system ect. I dont know just tickles my brain i guess. Anyone mess around with this stuff or even electric outboards??? Seen they have 30hp outboards that have been praised for reliability, ease of use, longevity and good range.

We had an electric out board for the sailing dink for the grandchildren to use around/in the marina as it did not push the dink very fast, but fast enough for them. When on Lake Union I use like to row the sailing dink, but many times used the electric to help get my back especially against the wind.

However now we are in Everett on the Snohomish River and the electric motor is not powerful enough against the current and the wind, so now we use a 4 HP Merc engine. Many boats use an eclectic motor for trolling at slow speed on the Puget Sound, but they use the main engine to charge. The resaon they use smaller out boards is the big many eninge will not go slow enough to troll. They are called a kicker. So they work for certain applications and conditions

Last year a 28 ft Bayliner engine froze up so they replaces it was two electric out drives, However the boat can barely do hull speed and it struggles in the wind. I don’t think they have left the marina yet. I don’t think they have very much invested and probable wished they have rebuilt/replaced the engine.


It seem if you are going to go elecrric you wold still need a small gen set to charge the bateries. Solar pannels are wothless in the cloudy/rainy PWN. My impression is you want to go down the path, you need a lot of money with very little pay back.

Yea i seen that price is a big concern. To me though the freedom from fuels is a very nice thought.

justinclay said:

Yea i seen that price is a big concern. To me though the freedom from fuels is a very nice thought.

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As has been stated in other threads, the cost of fuel is minimal in relations to the cost of mooring, insurance, maintenance, repairs, upgrades etc. If you have a vessel that is efficient, mine is 2 gph, and you put on a few hundred hours a year, your really not talking much money in the grand scheme of things. I have used electrics on my flat back canoe and also 14 ft aluminum fishing boat and love the no noise aspect and low speed control capability for trolling but don't currently see it as efficient primary power. Just MHO.

LaBomba said:

As has been stated in other threads, the cost of fuel is minimal in relation to the cost of mooring, insurance, maintenance, repairs, upgrades etc..

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Why is this component of the total cost of trawlering so hard to accept?

SeaHorse II said:

Why is this component of the total cost of trawlering so hard to accept?

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Hey Walt, not sure if you question/comment is meant in a positive or negative respect but from a personal opinion, after having an offshore with twin 350s and a walkaround with a 200hp outboard, I am ecstatic with my trawler and 2 gph and consider this cost as being minimal. The only way to go cheaper is to buy a sail boat, no thanks. Depends on each individuals perspective I would guess.

LaBomba said:

Hey Walt, not sure if you question/comment is meant in a positive or negative respect.....

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Good point! What I'm trying to say is that all this effort to burn as little fuel as possible, when compared to all the big ticket expenses one faces in our chosen pursuit, seems a little myopic to me.

We don't seem to bat an eye at a $2K bottom job or a $5K electronics suite, etc. but when it's time to buy fuel, we're all tied up in our underwear! To my way of thinking, "it's penny wise & pound foolish."
In other words, Allan, I support your position.

The US Navy is working on the electric propulsion for their ships, so it is possible. This USN system consists of very large electric motors driving propellers and diesel electric generators distributed around the ship. So, you could make an electric trawler if you wanted to, but you would still need diesel to run the generator.

It isn't very practical to use batteries. Take a DeFever 48 as an example, at 50,000 lbs displacement, 14' 4" beam and 40' 11" LWL it takes 80.9 HP or 60 KW to maintain 8 knots with no wind and no waves. Using Trojan T-106 6V gulf cart batteries, which are rated at 225 AH at 6 Volts they are capable of holding 225 AH * 6 V = 1,350 Watt hours or 1.35 KW HR each. Using 50% depth of discharge (to get better cycle life) reduces this to 0.675 KW HR. So for every hour of battery operation at 8 knots you need 60 KW / 0.675 KW HR = 89 T-105 batteries. With a battery weight of 62 lbs each, this equals 5,511 lbs of batteries per hour of operation. The battery bank to provide a 10 hour cruise endurance would exceed the gross weight of the boat.

Now lets talk about solar panels (and neglect the typical cloud cover in the PNW). According to Wikipedia, the most efficient mass-produced solar panels have energy density values of up to 16.22 W/ft^2 (175 W/m^2). To produce 60 KW at the optimum time of the day you would need 60,000 W / 175 W/m^2 = 342 m^2 of solar collecting area. If you limit the collector area to the length of the vessel, i.e. 48' then the solar collector needs to be 14.63 meters wide. Unfortunately the DeFever 48 has a 14' 4" = 4.36 meters so the solar panel will be over three times the beam of the vessel. Now, if you want to be able to maintain speed over a significant portion of the day (i.e. 9:00 AM to 3:00 PM) you will need to double the collector area. If you want to be able to boat with 50% cloud cover double it again.

Maybe if you built a long catamaran with a significant beam and made it very light weight you could set a solar powered boat speed record, but could you take it anywhere?

Im not saying its hard to except, im completely aware the cost of fuel is minimal to the overall cost. That don't mean you should totally get rid of the idea in general. I mean even though you would be saving a little on fuel. With the larger battery bank plus solar panels while your out on the water save on genset fuel. I just dont get why people totally dismiss the idea?? Is it bc people are scared of change?? Im no genius on boating ill admit that believe me. Just wanting to know the actual reason why people totally dismiss the idea.

Thank you portager. That shed a lot of light for me. So the main concern is the amount of batteries you would have to have in order to maintain a decent range? Could you cut a little weight by adding solar panels and a diesel genset??

justinclay said:

Im not saying its hard to except, im completely aware the cost of fuel is minimal to the overall cost. That don't mean you should totally get rid of the idea in general. I mean even though you would be saving a little on fuel. With the larger battery bank plus solar panels while your out on the water save on genset fuel. I just dont get why people totally dismiss the idea?? Is it bc people are scared of change?? Im no genius on boating ill admit that believe me. Just wanting to know the actual reason why people totally dismiss the idea.

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Read my previous post. I don't think anyone is dismissing the idea without giving it adequate thought. Conversely, those who are advocating it have given it insufficient thought. Take a look at the Duffy electric boats Duffy Electric Boat Company - The world's leading manufacturer of electric boats since 1970.. Here is So Cal they are ubiquitous. They are great for putting around the harbor and almost every dock has one in Newport Beach CA. Duffy even launched the first solar powered boat in 1979 Duffy Electric Boat Company launches World

justinclay said:

Thank you portager. That shed a lot of light for me. So the main concern is the amount of batteries you would have to have in order to maintain a decent range? Could you cut a little weight by adding solar panels and a diesel genset??

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What is practical, in the right climate, is adding solar panels help the battery charger and offset the load on the generator. Most boats consume much more house power than solar panels can provide, but where they do help is maintaining the battery charge while the boat is at anchor. Solar can also help by providing the float charge and allowing the generator to be shut off once bulk charge is complete.

This is a fairly simple way to utilize solar power without the massive expense of replacing the main engines.

How about a purpose built, light weight cat that has 8000 nm on just 8 Kw of solar?
Boat - SolarWave

Or a clunky, heavy C60 commercial cat ferry can cross the Atlantic on just 10 Kw of solar panels, does that not prove the concept viable?
transatlantic21: The world's first crossing of the Atlantic on a solar boat

wow, that solarwave is amazing...... exactly the idea/thought i had in my head.

justinclay said:

wow, that solarwave is amazing...... exactly the idea/thought i had in my head.

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It is just a matter of hull efficiency and displacement. My personal best is 32 w-hr per nm. To put that in perspective, using LiFePO4 cells, I've covered 80 nm on 60 lbs of batteries.

wow deck officer thats impressive.

justinclay said:

wow deck officer thats impressive.

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It would be if that vessel had a galley, head, and berth, but it is an electric kayak. Scaled up to something with comfortable cruising capabilities, then you would be looking at around 600 w-hr per nm instead of 32 w-hr.

ahhhhh leaving out the details haha

Justin,

To answer your PM, the main concerns is energy storage and production, using a light hull that is efficient. Cats and tri's are a good choice. You will never meet the energy density of fossil fuel, but if slow works for you (like 4~5 kt) you can size a lithium battery bank and solar panels that can give you 100 nm passages with a week on the hook, then another 100 nm passage. This is rather common Caribbean cruising, but without using any fuel.

Here is what I put together for the kayak.




MOV02923 - YouTube

by a week on the hook you mean letting your batteroes charge back up and then doing another 100 nm's? if so thats not too bad if your looking to take a long voyage wothout a time constraint.

That is what I meant, typical Caribbean cruising. The more panels, the less time on the hook to recharge the batteries. Reuben is running 6 Kw of solar on his cat trawler, so in 2 1/2 days he is ready, but his panels pretty much cover most of the boat and he has an all electric galley and A/C that is run off the batteries via inverter.

Thats not too bad though.

He even heats his water with the energy in the batteries. Is idea was for all creature comforts while on the hook without any propane, diesel, or gasoline usage. His dinghy is electric powered as will mine be.

Thats the same situation/mind set i have to be able to leave the marina for days if not weeks without worrying about dang on fuel. Let mother nature charge me. If it takes awile so be it. Not worried about fuel. Everybody says in cruising, fuel is the least of your worries. While that may be true if you live basically such as i with a high mechanical inclination. The other stuff isent as cost expensive as others who have marina's do their work. Im not better then anybody and dont portray myself as such I personally just dont have the money to pay 100 dollars an hour labor.

When someone else was paying the bill, I never flinched at a 1000 gallon per hour fuel burn. But that was during my merchant marine days, and the schedule or destination was determined by the shipping company, not me. My past cruising that was for me was on a Cal 40 sailboat. I'm still on the fence for future live aboard cruising, power or sail. If power, even though most here say fuel costs are of minor consideration, I'm not sure it is for me. Converting a current design to diesel-electric hybrid with solar appeals to me. Instead of having nothing to show for all the dollars burned in fuel other than new destinations, I would rather see a fully self sufficient boat that soaks up solar to be used at my discretion. With the cost of solar dropping to $1 per watt, and the recent drop in LiFePO4 prices, there is a pay back on investment, which there wasn't just 5 years ago.

Walt your right about the cost of boating. I paid almost 3k to get my transmission rebuilt and didn't think about the cost for over about 1/2 a day. But in fuel bucks that would have almost given me enough fuel to fill er' up. I've been thinking about fuel since I bought the boat but it gets the same milage my 29' hydrosport.
The current topic is taboo for me. I was all electric and solar for a long time but I just can't get over the cost and weight of batteries. I've got 6-71's that were built in the 50's. They still run and are pretty darn efficient. 1 mile/gallon total. That's about 11gallons/hour. Most of the money in an electric system would be the batteries and they need to be replaced at the end of there useful life. Motors don't, they go and go and go if properly maintained. Just my 2 cents.

"Why is this component of the total cost of trawlering so hard to accept?"


MOST of the expenses of boat ownership are hard to accept for many folks.

NOT doing Da Book preventive maint on the engine and noisemaker , hiring "cheap" labor to install or repair stuff , "cheap " chain and low cost unrated anchoring parts, all are boating costs that folks are attempting to reduce.

The next owner uses his bucks to attempt to catch up.

The fuel bill cant be postponed and passed on, so it is a major concern for many, and some of the reason many boats never leave the slip.

FF said:

MOST of the expenses of boat ownership are hard to accept for many folks.

NOT doing Da Book preventive maint on the engine and noisemaker , hiring "cheap" labor to install or repair stuff , "cheap " chain and low cost unrated anchoring parts, all are boating costs that folks are attempting to reduce.

The fuel bill cant be postponed and passed on, so it is a major concern for many, and some of the reason many boats never leave the slip.

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OK, I get it, but if indeed, that's the case, why do people choose this sport if they can't afford to play?

I love basketball but am a terrible dribbler but I don't expect the refs to allow me to travel on my way to the rim!

If the cost of fuel is truly prohibitive for some folks , shouldn't they consider a sail boat, row boat, kayak, etc where the cost of fuel does not impede their activity?

The "cost of fuel" is part (although small IMO) of the entry requirements for being in the game.

Again, to quote Clint Eastwood: (I loved Dirty Harry) "A man's gotta know his limitations!"

When my present 30 yr old Volvo MD17 finally rots out, I may consider going electric if the costs continue to fall. My hull is fairly efficient, and I've got sails to help me along when I feel like pushing 6 knots.

Diesel will be going up in price, that is without question. I knew that even before my 30+ years in the oil exploration game. But I look forward to higher prices; it will be the catalyst for change.
As a few posters have pointed out current diesel costs are a small part of it all. For me, my burn rate is about $2/knot. Peanuts! My beer costs are higher than that.

My reasons for considering electric are:
I would rather listen to the wind and waves rather than the rattley old Volvo.
I'd rather smell the ocean instead of diesel fumes.
I'm sure there is some preventave maintenance to do on an electric motor drive, but I expect it would be less than what is required with my old girl. In a bilge as tight as I've got, that will be a big plus as I get less nimble.
Also - my teenage kids would think it's cool if I popped a couple of solar panels on the roof.
The dealmaker for me - is that I won't be using a finite resource, (something that took 100 million years to create) to propel myself on the water for a bit of fun. If you think about it, that doesn't make a lot of sense.
Maybe I'd be better off not thinking about it.
La, la, La la te da Another beer please.