Can there be electric offshore race boats?

[gearhead]

I have seen offshore boats that have 500 gal gas tanks, if they were full of gas would weight over 3000 lbs.
Two big block engines with accessories, transmissions, cooling, out drives would weight in at 3000 plus.
I have seen engines cost 50,000.00 plus, Boats over a million dollars.

So for the sake of argument, lets not consider cost and figure out what it would take to make a boat that would go 50 mph and go for 100 miles.

With the light boat hulls available and the newer batteries available and the newest types of motors, what would it take?????????????

The boat could be perfectly balanced and stay that way all thru the race.

I don't want to hear why it can not be done, I want to hear HOW we can do it! I know it can be done!:drool5::driving:

 

[lohring]

I have some experience with both electric and offshore boats. Dry Martini had two 600 hp engines and a top speed of 85+ mph. We carried 400 gallons of fuel. Duplicating this with electric motors would require motors developing 900 KW. High voltage automobile AC systems run around 500 volts, so that would require handling 1,800 amps, probably divided among at least two motors. The real issue is batteries. Dry Martini could have run for about 4 hours at full throttle on 400 gallons. That's maybe 300 miles, though it would be a calm race to average those speeds. It would take about 1 1/4 hours to go 100 miles at 80 mph in our electric offshore boat. We would need a 135 cell (500/3.7) lithium polymer battery with 1,125 ampere hours of capacity. Since there needs to be some safety factor, let's say the battery would need 1,400 ampere hours. A single 3,7 volt 5 ampere hour cell weighs around .441 pounds. Lower cost cells might weigh .3 pounds. We would need a 135S 280P battery. That means 135 cells in series with 280 groups of 135 cells in parallel for a total of 37800 5 ampere hour cells. They would weigh nearly 17,000 pounds for the high cost cells or almost 12,000 pounds for the low cost cells. Dry Martini's all up weight was around 10,000 pounds. If we bought these cells at retail prices in packages of 5 cells they would cost close to 2 million dollars. The lower cost cells come in at about $600,000.

Lots bigger batteries are available for vehicle applications and I'm sure the prices would be more reasonable. However, this was the approach we used for our electric hydro. The motors and speed controls probably would be custom designs, because weight isn't a problem with really big electric installations like locomotives. I don't know any electrical engineers that are interested. A lower drag type boat would help. However, cats don't like weight, and the Dynaplane type planing hull is yet to be proven in offshore conditions. It still could be done, but it would be very tough to compete with even diesels in a short race.

Lohring Miller

 

[rschap1]

WOW
Now THAT is an ANSWER!!

 

[gearhead]

Lohring
Thanks for the reply.
I agree that competing with the big boys would not be realistic right now. What about a smaller boat, say a 24 ft with one electric motor and run the speeds that the early offshore racers ran. Would 40-50 mph for 100 miles be realistic?
We need to walk before we run.
If it was still a weight issue what about going 50 miles?
50 miles at 50 mph in an electric boat would be real impressive.
An offshore race with electric boats on a 10 mile course would be five laps or a five mile course would be 10 laps, that would make for a reasonable race. It would be about an hour long race.

 

[Ratickle]

I knew he would have the numbers. You don't test an electric boat at over 100mph without research and talent.....



I keep coming back to the best they can do with a reasonably priced car, the Volt, is about 45 miles total. And all of us boaters know the difference in drag between a boat and a car....

 

[T2x]

If you look at some of the large cruise vessels and railroad locomotives, there are any number of electric propulsion systems, but, as was already pointed out above, the battery weight is still untenable. The way that electric propulsion is most often employed is through a diesel/electric combination. That requires fuel and a diesel motor driving an electric motor which gives superior acceleration and braking to the internal combustion motor alone. If you want to run solely with electric power, you will either have to come up with a much more lightweight battery design with huge capacity beyond anything currently available or explore some other means of generating electric power. Solar certainly won't do it, but perhaps some technology around saltwater or oxygen ionization could be developed wherein the very atmosphere around the boat could be employed to provide electrical energy. Of course when that becomes feasible...your local gas station will promptly go out of business as the technology would change a lot more than simply offshore racing.

Another approach might be an energy transfer grid along the lines of the flat top cell phone chargers currently available. This would mean some network of power generators along the race course that could send electrical impulses to the boat as it passes. In all probability this would electrocute or burn the occupants unless they were in a shielded environment.

And , finally, there's always the nuclear option.

T2x

 

[rschap1]

The "hybrid" cars seem to be a lil' more feasible as a stepping stone until battery technology allows more advancement.
Maybe similar would be attainable on the water...
Small diesel generator and some of the reclaiming technology may be drawn from too.
I know that there are no brakes to use for generating juice, but maybe...who' knows.
With all the GIANT ships using such set ups, downsizing some of that hardware would seem like an easy experiment.
Rather than carrying 100,000 pounds of batteries, carry 1,000 pounds of batteries, a 500 pound generator, and 500 pounds of fuel for that...

Maybe???

 

[gearhead]

As far as the nuclear option, I think Russia would entertain a sponsorship. I hear they have a few nuclear power supplies left over from their sub fleet!

I read an old article about electricty being transfered to vaccum machines and household appliances without electrical cords, seems a little scarry to me too.

As far as generating electricity from salt water I know that can be done but I think you use sacrfice metal and it might end up more expensive than fuel plus EPA would have something to say. If it could be contained somehow that would work great! You could set your little module over the side of the boat and let it charge the batteries while you go get a bite to eat.

It sure seems like we should be able to make a boat go 50 miles at 40-50 mph with the technology we have now.
According to lorhing calculations and me doing a simple and uneducated division of his figures and starting out with 17000 lbs of batteries we can divide that in half to go 50 mile instead of 100 so we are down to 8500 lbs of batteries. Next we only want to go half the speed so divide that by two = 4250 lbs of batteries. Next we use a smaller boat and one electric motor, instead of 1200 hp we might need 300 hp and maybe divide the batteries by two again which = 2100 lbs., seems like that would be doable. I know there are a lot more variables I didn't account for but it still seems possible.:driving:

 

[old377guy]

or have the hull panels themselves be piezo electric generators - the rougher the water the more juice.:sifone:

 

[lohring]

Early in my career I worked at Electric Boat on manuals for nuclear submarines. There, electric drive was used in experimental subs like the Tullibee because the gears between the turbines and propeller were very noisy. The problem was packaging a powerful enough motor/generator system in a small space. Hybrid cars make sense because sophisticated power management systems can recover a lot of the power lost in braking. Boats don't have this opportunity. Electric transmissions are more flexible than gears where you are trying to match engine and output shaft speeds and loads. However, in boats you usually don't have the variable loads a rail engine does. Efficiency is an issue as well. Gears are very efficient at moderate gear ratios.

All the above plus the still relatively low energy storage capacity of batteries compared to liquid fuels make electrics hard to justify in boats. Fuel cells might be an answer if they get developed more. Our electric boat was a stunt for fun. Because we drove it like all the other boats at the kilo run, it looked like it had the same capabilities. It's success obscured the real problems.

I think you would need to couple a low drag design with a custom power plant for success. However, offshore racing is very dangerous and designers are careful as a result. Cats are also a possibility, but flying them more for low drag gets very scary. There is a reason I'm not the driver in these efforts.

Lohring Miller

 

[Ratickle]

There is a reason I'm not the driver in these efforts.

Lohring Miller

:sifone:



Maybe you can get Rich? Make an electric Switzer Wing? He knows about drag and flying low......

 

[gearhead]

Lohring
It looks like you have some formulas that help determine what is needed, I was wondering what kind of battery and motor weight we would have to get an electric motor to produce 250-300 hp for 1 hr? What kind of batteries would be the best?

I am interested in exploring this a little further if it looks possible. The weight would determine the type of boat to use and then try to reduce the drag.

Maybe a needle shaped displacment hull that would slice through the waves and have some small hydrofoils to lift it in calmer waters? Wouldn't need and throttle man ( set your RPM on the computer) or a navigator (we have GPS)= less weight.

I did simple division in the previous post but it could not be very accurate.

By the way I am an ex submariner, was a missile tech on the Abraham Lincoln and the Robert E lee. Helped decomision the Abraham Lincoln and we were the first boat in the trident sub base in Bangor Washington.

 

[lohring]

Drag in high speed boats is all about reducing contact with water. Since water is 800 times as dense as air, The drag in water is 800 times as much for the same object. Try sticking your hand in the water at 80 mph as a test. LOL The best answer is the Russian ekranoplans that don't touch the water at all at 200+ mph. The next is the three point hydroplane that Chip Hanauer once described as a wing with training wheels. That was our approach with our electric boat. Neither of these designs would work under real offshore conditions. Quite a few people would argue that cats, the next in low drag hull styles, aren't suitable either when it is rough. Submarines are at the opposite end of the scale. Deeply submerged submarines are completely unaffected by surface conditions, but have huge skin friction drag. That can be overcome with equally huge power which is why they can out run surface ships in a sea. Wave piercing ships are somewhere in between submarines and surface ships. They have lower drag than displacement ships in a sea, but higher drag than planing hulls.

Our offshore boats are an attempt to push small boats fast in bad conditions. Stability and drag in waves, in that order, are the most important factors. We overcome the drag of stable hulls (deep vees) with cheap power. That's still the best solution as far as I can see. It doesn't work with today's electric power plants. In submarines again, the 30 +- knot speeds took 30,000 hp geared turbines, but quiet running in the same boat was limited to around 5 knots on electric power. Fast but quiet subs used natural circulation reactors and direct drive turbine propulsion. Today's subs were built long after I left, but I bet the same principles still apply.

I can see heat racing electric boats, but endurance with performance isn't in the cards yet.

Lohring Miller

 

[T2x]

:sifone:



Maybe you can get Rich? Make an electric Switzer Wing? He knows about drag and flying low......

I'm gonna rock on to....

Electric avenue.....

 

[lohring]

I'm gonna rock on to....
View attachment 73683View attachment 73684
Electric avenue.....

And that's in absolutely calm water. It looks a lot more like this in a real race:


I wrote an article on electric power for model boats here, but the principles are the same. One horsepower equals 746 watts and the power in watts is the current times the voltage. Modern electric power plants can convert over 80% of the supplied power to shaft horsepower. That compares with less, usually much less, than 30% of the chemical energy in the fuel for internal combustion engines. However, liquid fuels store a lot of energy very inexpensively in a small package.

Lohring Miller

 

[Ratickle]

Rich, What's the roughest water you ever raced a wing in?

 

[T2x]

Rich, What's the roughest water you ever raced a wing in?

I actually never raced a Switzer wing...Back then I raced in a progression from Powercats to Glastrons to Allisons to Eltros, to a Milesmaster, to Molinaris, and finally Seebolds...after that we turned our attention to building Offshore Cats. I did race a Switzer concave bottomed "Shooting Star" in one event which turned (or didn't)very much like our present wing..with no where near the aero lift. The head on wing shot above was taken of me at a 2010 vintage event ( not technically a race) in the St Lawrence Sea Way crossing a Great lakes oar boat wake in Clayton harbor (camera lenses flatten wave height perspective).

Contrary to Lohring's earlier point, however, cats can run quite well in rough seas (up to where small craft warnings cancel races).... Cats have won numerous rough seas events in the past 30+ years and we built some of them......Brownie and Clive built more...and Peter built the best.



.

 

[lohring]

Don't get me wrong, I love cats, and my partner Mike Bontoft worked on some of the early Cougar cats in his youth. However, my comment about "some people" reflects the entrance limitations in the Cowes-Torquay race. No cats.

Lohring Miller

 

[T2x]

I do have one question. What does any of this have to do with "Historic and Classic Offshore"?

 

[Bobcat]

:huh::huh: :rofl:

It is a very cool conversation though