Electric Ski Boat

First, a couple of facts:

1) My 50.00 18v Ryobi hand drill will handily drive a 4" lag bolt through a 4X4, or hang drywall all day, or put a hole saw through a solid oak door to install a deadbolt with no problems. The motor is about the size of a half roll of quarters and I'm assuming it works via extreme gear reduction. The batteries (NiCad) last for weeks with regular use or days with heavy use.

2) My ski sets only last 1-2 hours, if that and my boat is always stored near an electrical outlet for charging if needed

3) Removing my SBF V8 and gas tank will free up nearly 1000lbs of weight in the boat- that's a lot of room and weight for batteries.

4) Battery and electric motor technology are getting better and better these days. Electric motors can generate gobs of torque instantaneously and batteries are getting smaller and more powerful every year.


Now, the question:

Why can't someone create a battery powered ski boat? Most ski sessions don't last too long and the majority of your time on the water is just iding around to pick up skiers. It seems like a rechargable all-electric boat would fit the need of skiers and boarders perfectly. Zero emissions and silent power. No ZDDP oil changes or engine work! Would this not be awesome?

m3, you got the thinkin cap on today

I've mildly considered selling my GT40 and investing the proceeds towards the new powerplant but unfortunately I'm no electronic engineer. I know that with the right gearing,prop, and electric motor you would have one beast of an electric ski boat.

Joel,

You need to pick yourself up one of those hybrid cars and swap the motors out, or better yet an old decommissioned Nuke Sub, throw a tower on it, run her below the surface for no wake, may have to rethink the course setup though cause those anchors may get in the way.

Seriously though, a buddy has an electric boat and it is really cool, think it's a Spincraft, it runs almost silent, not very fast though.

Here's your new boat M3

http://www.boesch-boats.ch/

TRBenj wrote: 91nautique wrote: Here's your new boat M3 http://www.boesch-boats.ch/ Heres the smallest electric powered one. Better bring your wakeboard, top speed is only 21mph.

That seems like a pretty weak attempt. Looks like a direct drive motor setup. Right idea, though. Without being an electric motor expert it seems like you could get some major gear reduction going to increase the torque a bit. I keep going back to my 18v drill being so powerful for its size. Imagine scaling that same design up to what, 25x the size?

I was buying into it , thought it was a good idea .

Then BANG , You said silent power . That took the excitement right out of it .

Maybe we could mount Quinners stereo onboard with classic CC engine tones . That would make it all better.

If I crunched the numbers right....
1KW=1.36 HP
50KW=68HP
I think Petes Atom Skier Tops that.
And for yall that want the sound we are working on that problem, It is in the think tank now .As it comes to the surface it will be posted here.

Dude, First the myth busters thing, now this... put down the herb.


bj

8122pbrainard wrote: Yes there are electric tug boats but they have a means of generating power and are not on batteries. Using this all battery Boesch as a example, I don't feel anyone would be happy with its performance. The Boat Doc is certainly on the correct track with the HP of the Boesch electric. They are using a 3 phase AC motor with a inverter setup for frequency-speed control so I'm comming up with roughly about 115 HP. (198 amps X 250 volts X 1.73 - 3 phase multiplier Divided by 746 with 100% efficiency - efficiency is unknown so HP will be lower) That's not much HP compaired to gas but considering the top speed of 22 MPH is about right. Yes, my little Atom with the 60HP does better than 35 but of coarse is a lighter and smaller boat. Depending on the type of battery they are using, I figure they have 20 or 21 hooked in series. (they look like gel cells so it may be 20) A 4D gel gives you 180 amp hours so with that size you will only get about a hour of boating/sking (at 22MPH!!) before the volts are pulled down to the recommended min. This is if you were using the full HP drawing the 50,000 watts (198 amps). Joel, With a gear reduction, yes, you would gain torque but you will loose RPM which means swinging a larger prop. The reduction drives in our gas ski boats now only improves the hole shot due to the larger prop. I don't think that is the answer. A electric motor has plenty of torque and increases with RPM. As with electric cars, I feel the battery technology just isn't there yet. I wonder what the wake looks like? With 20 4D gel cell, that's 2600lbs of ballast! (130lb X 20)

Ok, finally some good technical input on the subject! Exactly what I was looking for. An assumption I had made was that the electric motor would be capable of much higher RPM then a gas or diesel. So, with the reduction I was thinking that the reduction would "reduce" WOT RPM to 4400 RPM or so from something way higher, like 10k RPM or more. If that's not possible then oh well. Going back to the example of my drill, the reduction is pretty extreme, which is what initially got me thinking about this. Far more than a 1.5:1 or 1.23:1 ratio- I'm talking 10:1 or more. As another example, my RotoZip's 5A electric motor turns 30,000 RPM (just an example- I'm not thinking of powering a boat with a RotoZip). I'd imagine with some reduction you could see some major power at 4400 RPM. So, smaller, weaker motor with high RPM and serious redux. Is that feasible?

Pete- This should be right up your alley... except for the price tag! Twin screws in a inboard runabout would be great. Their website shows a video of someone wake boarding. We also have a Fiberglassics member that has grafted a 105# trust electric trolling motor into a old outboard case. They are just getting ready to test it.

EDISON BOATS

Still, that's thinking outside of the box- why have one big motor when perhaps two smaller ones would work better? There has to be a solution here, although it may defy conventional thinking.

Here's some more on the Boesch:
http://blog.tradeonlytoday.com/dealer_outlook/index.php/?p=52

Wow! Okay, all "electric boat w/o V8 sound" nonsense aside...

...just kidding; the ideas are interesting and sad to say (for those (like me (and most of you)) addicted to V8 sound, they are probably necessary ideas.

I can appreciate thinking, as was mentioned above, "outside the box" except when it comes to inboard sound! That's where I like to think inside the box; and I mean actually inside the box, the dog box, the engine box! It's easier to think "period" with V8 sound in the background. It drowns out every distraction!

Someone thought outside the box once with digital cameras. I'm sure everybody by now has noticed that their digital cameras make a click sound that sounds like an old mechanical shutter "THAT ISN'T ACTUALLY IN THERE!"

You can turn that sound off on many digital cameras. It's like "silent choice" (or captain's choice?) for shutter bugs.

It's for "getting old dogs" (like us), but in the camera world, who can't imagine that their camera has actually taken a picture without going "CLICK!"

Similarly, I can't imagine a skier yelling "Hit it!" and the next sound you hear closely resembling the sound of a Makita (er, I mean Milwaukee) cordless drill!

Seriously, all "sound" discussion aside, the actual power capability still apparently has a good ways to go. You notice all references to skiing are directed toward wakeboard, trick ski and/or wake surf speeds (i.e. "SLOW"). Even without using my handy "km/H to mph" converter, I'm seeing numbers that basically mean "slow."

Here's a good conversion chart for aging skiers:   

< 50km/H = "Too Slow!"

Since 50km/H means close enough to 30 mph, it means those numbers you're seeing with those nifty electric boats are still "Too Slow" for your basic old dog skiing (barefoot and slalom).

I do like the old wood designs some of those companies are doing the E-boats in - those are some pretty boats, but I think that's just another attempt to entice a certain age of boaters into the fold.

Still, I guess I could live in a world without the super cool sound of gas engines provided the electrics (or whatever (hydrogen maybe??))were as powerful as gas AND less expensive to run. Think about folks that lived life using horses and liked it that way. I'm sure that was a tough transition for many.

Maybe that's why the automobile's first power plant's (gas engines) were said to generate
something cleverly named "HORSEpower!"

I gotta agree with Pat...why silent? How many heads would turn on the ramp when you fired her up? And ain't that at least part of the reason we are here?
Better ease up on the reefer.

john

Aemmer, who did you work for? i did alot of work for American commercial barge lines down in South America,
Ive heard of these lines snapping and never seen it, the crew always told me about them snapping and to stay away we we were underway