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electric airboat

U

Uhairball

Well-known member
A quick ebay search shows a complete drivetrain out of a tesla model 3 for $4200 and a long range battery pack for $10000.
Weight for both should be around 2000 pounds. I don't know what computer would be needed to get this to work. Who wants
to be the first to try it? If a tesla car could go 150 miles on a charge, any guess on the range in a boat?
 
I've thought about it, but the battery technology isn't there yet. My entire boat with fuel weighs like 1800lbs, the battery weight and range is the deal breaker. My boat gets like 3mpg, rough math says that battery would only go 15 miles (if the car gets 30mpg).
 
While I hate the politics of green energy, (taking American jobs) you might be onto something here...
My US Navy nuke powered fast attack submarine had a "battery room" in the very front of the sub, (below the torpedo room).
That room housed enough batteries to run on for hours-even days when conserving power, (and how even WWII "diesel powered" submarines operated-they used batteries when submerged). We'd come up to periscope depth and crank the diesel to charge the batteries every so often, (on a schedule unless running ultra silent mode)
So it's not old theory in maritime use-but me...I'm freaky paranoid about electrolysis / battery acid / corrosion type damage on an aluminum hull that cost so...much LOL!
Fiberglass boat maybe?
Following...
 
Slidin Gator said:
Yah, another project is just what I need... It would help my carbon footprint for sure, since I would be home building boats instead of burning fuel!
Click to expand...
Since we are on the topic, one of my present shop projects could be called Renewable Energy. I seem to accumulate a butt load of waterlogged gear, engine and tranny oil during hurricane season (or is it hunting season:whistle:), plus all the used frog cooking oil. I am looking to renew that into AC and a working oven for the missues when FPL fails.

I have a barely used 3 cylinder, mechanical Yanmar diesel that I picked up for a song a year ago and a just received today 16.5 kW alternator head to form the basis of my hybrid household power system. When this is done, the electric airboat pits had best be within trailer haulin range, because I ain't loading it in one of my boats.

Yanmar.jpg



16.5 kW Gen Head #1.JPG

16.5 kW Gen Head #2.JPG


Some figures to consider:

1 Hp = 3/4 kW (1.33 Hp to a kW)
1 kWh = 1 kW solid for 1 hour
A really good 12V lead acid deep cycle trolling motor battery provides 1.4 kWh of storage

I find Tesla Model 3 at 211 kW = 280 hp. The huge advantage of electric is an almost flat torque curve, so the boat will jump off the line, unless it loaded down with 2,000 lbs of battery. That's output power, assume 80% drive train efficiency and the Tesla draws 265 kW electric input at WOT. Run WOT for 5 minutes, 265*(5/60) = 22 kWh energy. So that is 16 deep cycle batteries to run 5 minutes, a bit less than 1,000 lbs in lead acid, call it 300 lbs in hot rod lithium/super cap form.

Now, back to power vs. energy, my new genset will make say 15 kW continuous, I'm gonna need a 1-1/2 hour pit stop to recharge the 22 kWh for another 5 minute blast.

As for solar, covering the boat in panels will be about right to run an on-board beer fridge, but won't make a dent in another 5 minute blast. By the next morning, the fridge will be dead and the last beer will be warm (or gone) and the damn prop still won't turn.

Solar Airboat = beer cooler you can drag through the swamp. Eventually it will run out of beer and you will leave it behind.
 
Any idea what RPM the tesla motors turns at WOT? if you were to use it in a direct drive application, you would limit
the RPM to around 3000 RPM and would never use WOT which would extend your range. Maybe not enough, but
better than 1000'
 
I don't know about the Tesla, but you can buy a Eluminator MACHE drive assembly from the electric Mustang as a crate engine from Ford Performance for $4,095. 280 Hp peak.

ELUMINATOR MACH E ELECTRIC MOTOR

The drive unit sits where the rear axle would be with outputs to both rear wheels. It weighs 205 lbs and has 9.05:1 internal gearing vs. motor max speed of 13,800 RPM for maximum axle output speed of 1,525 RPM (118 MPH with 26" diameter tires). Peak motor Torque is 317 ft-lbf, applied through the 9.05 ratio, but the torque must be way down at max RPM.

You do not want a direct drive electric motor, it will be a monster without gearing.

 
Maybe in 10-15 years when the battery technology gets better. I have solar panels on both houses enough to cover the majority of the power bill (40-80kWh per day depending on the time of year). If I had a camp, I'd run it on solar, put up a charging station, and you can basically have unlimited airboat fuel.
 
While my posts here do come off as anti-solar/green, that is far from the truth. I am a hunter and outdoorsman, by default that means I am a conservationist, no woods, no wildlife, no fun. I am practical, the electric airboat is a big nut to crack, bigger than electric planes, there are much better places to focus that net bigger overall benefits. Best move I ever made was my solar water heater, been through 17 years and 3 hurricanes providing plenty of hot water, I estimate it has saved me $17K in electricity, just had to train the family.

Using Wikipededia as my source, 1 gallon of gas in the US (assume 87 octane) is equivalent to 33-1/2 kW-hr of energy when applied to transportation. That means the 20 gallons of AV gas that I burn in a typical day running is equivalent to 670 kW-hr of electric power.

Gasoline gallon equivalent - Wikipedia

By the numbers, 670 kW*hr = 210kW * 3.2 hours of WOT on a Tesla/Ford 210kW/280Hp electric motor. It also feels about right for the duty cycle, total hours and power level that I run in a given day.

Compare that against a home solar installation. I have a 600 ft^2 (15x40) section of my shop roof facing south that I have always wanted to cover with solar panels. I assume 20W/ft^2 for the panels, 20*600 = 12,000, that is 12 kW peak, 6-8 hours per day in S. Fla., I'll use 8.

8*12 = 96 kW-hr of solar, 2.9 gallons of gasoline equivalent, from a days' worth of sun on my shop. Not including cooking hot dogs, drinking beer, running beer cooler, running wife's A/C etc. etc.

So yah, a series of giant solar arrays next to closely spaced camps all over the glades, we all running square a$$ hulls that jump on plane and take no power but track like flying saucers (and maybe look like them hoover damn (damn hoover?) craft) so we can beer hop and poker run the glades. Yep, that's possible.

The future sucks, best we ignore it.
 
I did an analysis of this on this forum several years ago and can't for the life of me find in the archives.

The super short version is your 2000lb battery (I used the same weight in my numbers previously) would give you at best about a 20 to 25 mile range for your boat if used for light cruising duty only.

I frequently give tech talks to early career engineers. One of my favorite topics starts off with a simple statement that has been true for a milenia.....all of the worlds problems can be solved with a better battery.

I cant really type out what follows that statement, so next time anyone crosses paths with me in the future I would be happy to give, "the rest of the story." (o7 Mr. Harvey)

You can build an eABoat today. It will weigh in at around 3000lbs and be a 2 person ride with very modest range.

Or, you can build one that will run 400feet and embarrass everything that is brave enough to run against it. Just can't run it more than once an hour between charges..... the motor will weigh about 70lbs and the battery will come in under 50lbs with the system capable of producing 600+ hp....easily.

I am going to use this one too...

"The future sucks, best we ignore it"
 
Taking a look at electric remote controlled aircraft that can fly for 15+ minutes on a battery the size of your thumb, using
direct drive, then figuring out to expand that to a small airboat, the future may be closer than you think. I believe these
spin at 7000 or more rpm. What prop would an airboat need to approach that?
 
Uhairball said:
Taking a look at electric remote controlled aircraft that can fly for 15+ minutes on a battery the size of your thumb, using
direct drive, then figuring out to expand that to a small airboat, the future may be closer than you think. I believe these
spin at 7000 or more rpm. What prop would an airboat need to approach that?
Click to expand...
I used to fly rc airplanes, in a decent size plane, the battery is half the weight of the plane at least. I used to fly gas, but my friends were already converting to electric at the time. It was for the same reason, battery technology got better. This was 8-9 years ago, but the batteries had to weigh a good 2-3 lbs in a 5-6 lb plane. I agree with you guys above, it's not going to be do-able for normal ride type boat until the technology is there. My solar panels are 300 watt, installed 5 years ago, my neighbor just replaced some of his with 500 watt panels to up his output. It might be decades, but when the battery tech is there, it was be bad ass to have an electric airboat. An iphone has more computing power than the first space shuttles, it takes time.

Edit- now thinking back on the RC airplanes, it was also the introduction of brushless motors that made them possible. I'm only looking at this from a battery perspective, but when they make the motors more efficient then wouldn't need such big battery storage.
 
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A bit off topic here, the battery weight and longevity is killing the concept in my humble opinion, in airboat world, it is weight vs horsepower and hull displacement to water or ground, that said, at that weight, why not a 4 cylinder Perkins turbo diesel in the hull with a hydraulic pump to drive a hydraulic motor to spin the prop, geared accordingly, a bobcat skidsteer will virtually run all day moving dirt, only one drive motor spinning a prop set up correctly would likely be very efficient.
 
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