Check this out!

[jward]

http://www.youtube.com/watch?v=AQiV_...eature=related

[core-rider]

"We got batteries, what have you got?"

I've got a hot water shower and a heater! :-)

Seriously though, I like where Epic has taken the wake boat. They did some innovative things with the 23V and took it to another level with the 23e. It's just too bad the fuel savings is eaten up by the boat cost since batteries are still too expensive.

[SkiTundra]

We'd worked all of this out a year or two ago. IIRC we'd figured that the Tesla powerplant could give about 3 hours of pulling which for most people would be a full day (probably not enough for heavy users though) and then charge overnight. A day of elec would cost about half what a day of gas would, depending on local rates. HOWEVER, what I learned with my future LEAF though is that overnight rates for charging are about 40% less than standard residential rates. Replacing batteries could be quite expensive and I'm not sure we know how long the current technology in Tesla/LEAF/Volt/Mini-E will go.

Besides Epic there's:

http://www.boesch-boats.ch/site/boat...et_language=en

Kinda on the slow side IIRC.

[horkn]

Daniel, one thing about the gas to battery relation that you are not figuring in is the weight and size of the v8 gas motor, all the cooling and associated stuff. Electronics, even an electric motor with enough power to propel a boat and it's load, would be a tiny thing in relation to our current motors.

I really do like the outside the box thinking of an aluminum ski boat. Ranger and others have been doing it for years and they look nice too.

The welding on them is nearly impossible to tell it is no FG. My friend won a new ranger Aluminum boat in like 96, and it still looks great, no paint issues or anything.

[SkiTundra]

I don't think the weight diff is actually very big. Batteries aren't light. However, with electric the weight comes in a bunch of smaller packages that can be distributed for optimum performance. There is also a mfring benefit in that a wakeboard boat and slalom boat could be identical except for where the batteries are placed and this could actually be done by dealers which would help stocking costs. For that matter, a family that only uses their boat an hour or two a day could purchase fewer batteries thus potentially giving them a lighter and better slalom boat that with ballast could still be a great wakeboard boat.

[DanielC]

Trust me, I would like not to have to import about 70% of the oil into our country so we can power our cars and boats.

I do know an electric motor is much smaller, and lighter than an internal combustion engine. But that advantage is useless, because of the size and the weight of the battery for a comparable range.
Again, show me the battery about the size if a coffee cup that has the energy to push a car about a mile, at 55 miles per hour.

[SkiTundra]

Your coffee cup comparison is valid at a micro level, but I don't think at a macro level. What's important is to compare total system to total system. The Tesla powerplant (motor + batts) can, for the same approximate weight as as an EX343+xmission+fuel, deliver about 3 hours of towing (based on computations of HP/Torq between the two). I assume a lot of this has to do with the efficiency of the electric system vs that of the gas system, though I didn't think electric was that much more efficient, particularly for this application.

3 hours and the pulling power of a 343 may not be good enough for you, but it is for me (and others). And I'd guess the 'fuel' costs of electric are likely about 1/5 that of gas given overnight charging discounts.

[DanielC]

At the Portland boat show, there has been an electric boat on display. it was made by a company called Edison Marine, and they had a website. the website is gone away, but here is a review on the boat from another source:
http://www.wired.com/autopia/2009/01/edison-marine-p/

When I talked to the person at the boat show, he told me the approxamate time and speed specs in the article.
Speeds up to 30 MPH, and a running time of 8 to 10 hours, at 5 to 7 MPH. I asked him about run time at a reasonable running speed, and did not get a really good answer, but the boat was very new, and he probably really did not know.

This boat would be great for idling to shore from your anchored yacht, in a no wake zone.

The Tesla sports car gets good range because it is a low slung sports car, with very low air resistance. A gas engine in this type of vehicle is probably capable of 40 to 50 MPG.

The reason I bring up the coffee cup of gasoline thing is this.
Most people do not realize how much potential energy is in gasoline, or other petroleum based fuels.

Again I will say, I do not like buying gas. I do not like the fact that some of the money the US spends on gas goes to middle eastern countries who are not our friends, and who support terrorists.

If you really want an alternative energy fuel source for your boat, look into converting it to run on compressed natural gas.

[SkiTundra]

Let's get back to Daniels cup (sounds religious, appropriate for Nautique!). I burn about 3 gallons per hour of use so if I pull people for 3 hours I'll burn 9 gallons of gas out of 38 gallons capacity so I'll use less than 1/4 of the gas in my tank. 3/4's of the gas (or the space it would normally take up) isn't necessary for a full day of skiing for us. The Tesla battery system that will give me 3 hours of pulling takes up about 20% more space than a 38 gallon gas tank and a whopping 7 times as much space as the 9 gallons I actually use for 3 hours of pulling. (In Daniels cup I'd need about 7 cups of battery space to his 1 cup of gas)

So what?

If I want to pull for more than 3 hours per day then this isn't the boat for me. I don't know that I've ever put more than 3 engine hours on my boat in a single day so not a big problem. Granted, if I did want to go longer one day I'd not be able to.

The batteries take up 20% more space than my fuel tank, but they are also more configurable so I'd calc this as a wash. HOWEVER, the motor itself is much smaller so in the end I actually gain a fair amount of real space and even more usable space.

[SkiTundra]

According to Epic you can wakeboard for 1 hour on batteries, or surf for 3 hours. Assuming they built a version for slalom they'd estimated 1.5 - 2 hours with their current battery/motor system. So, we know it can be done to at least a somewhat reasonable level in a boat. Not sure how their powerplant compares to Tesla or others, maybe someone else has time to do a comparison...

Also, over any given amount of use their boat uses, according to Epic, about half the fuel of a conventional ICE to produce the same results. This would indicate that ICE>Generator>Electric Drive (hybrid) is twice as efficient as conventional direct drive ICE in a towboat. Thus, you potentially need twice as much energy from gas for a direct drive as energy from electricity for an electric boat. I'm writing as I'm thinking so I may be missing something here.

[DanielC]

Here in Oregon, they are promoting electric cars in a big way. They are doing this, even in spite of the fact that we have to burn coal and natural gas in Eastern Oregon, to make electricity. For those of you not familiar with the Pacific Northwest, we also have a lot of hydroelectric power available from the Columbia river, and its tributaries.

There was an article in the local paper today about homeowners having to probably upgrade their electrical service for a 220 volt charger so it is possible to fully charge the electric cars in 4 to 6 hours. The article also mentioned the capacity of the battery in a Chevy volt as 16 Kilowatt hours. That means the battery is capable of supplying 16,000 watts of electricity of an hour, or 1000 watts of electricity for 16 hours. This sounds like a lot, and it is a lot of electricity.

Now, lets convert this amount of power to a boat engine, and measure it in horsepower. 746 watts equals 1 horsepower. 16,000 watts equals 21.45 horsepower. The Chevy volt battery can supply 21.45, HP for an hour.

Ever tried to waterski or wakeboard behind a boat with a 25 hp outboard motor?