I want an electric Hydro-cycle!

[juiceclark]

I watched a program about the Tesla the other day - that's the electric sports car all the tree-huggers are all excited about. I guess it really does look better than a freakin' Prius! Anyway, the powercell in the Tesla is just a big box full of thousands of those lithium-ion, cigar-shaped cells...like you'd find in an electric screwdriver. They said it will do 150+mph...I wonder if it can for more than 50 feet without runnin' out of juice?

http://www.teslamotors.com/design/under_the_skin.php

To the point: I never liked PWCs because they are loud and obnoxious. But what if you created one with a thousand little waterproof slots for the batteries safe and dry in the hull? You could easily arrange an electric motor inline with the waterjet and have a nice, quiet and rechargable ride.

I really like the design of the Hydrocycle made in the late 1960s. I'm sure you could make it wide enough to put a thousand lithium ion batteries in the hull with plenty of displacement left for people. Hey! I'm just a financial consultant/dummy. You marine architect/engineer geniuses should get on this right away! (promise to send a check if you make $? You can add custom features and sell it to Harley-Davidson)

http://www.fiberglassics.com/hydrocy...yclebxx004.jpg

http://www.fiberglassics.com/hydrocy...yclebxx003.jpg

Tony in Sw FL

[Kay9]

And then at every beach in the world you could run extension cords to recharge it. Of course life guards would have to swim in full rubber suits so they dont get shocked. Of course the towing buisness like vessel assist and towboat us would love a pwc that runs at full power for 15 mins and then dies at sea, with no possible way of recharging. But the bartenders on the beach will be able to sell a lot more drinks to electric pwc riders while they wait the 6 hours for there next 15 min ride.

K9

[tinhorn]

Nice car. They estimate a 200-mile range (more than adequate for - what - 95% of our driving?) which probably equates to about 4-6 hours.

What makes this happen, and just as importantly, what makes it happen SAFELY is their battery management:

The Battery Safety Monitor, mounted inside the battery pack’s protective enclosure, measures voltage, current, acceleration, tilt, smoke, moisture, and more. Like the controller for an airbag, the Battery Safety Monitor responds to an emergency - in this case by automatically disconnecting the battery pack from the vehicle and shutting down power to the car and to all electric cables in the car.

If you're crazy enough to load up a PWC with batteries, I don't see why current (hahaha) electric vehicle components designed for converting gas cars to electric couldn't be adapted - I don't think you need this cutting-edge glitz.

[drshaddock]

Originally Posted by tinhorn

I don't think you need this cutting-edge glitz.

I agree--look at the Briggs and Stratton Etek series of motors. They range from a 22-lb brushless 6HP that runs only 100A continuous (but can handle up to 300A short-term which is about 18 HP) to a 30-lb high-torque lower rpm version that is about 8HP. Bear in mind that some electric motor proponents suggest you only need 1/3 the HP of a gas engine or 1/2 the diesel... The odd thing about the Eteks is that they basically put out torque dependent on amperage--a fixed amount of torque per amp. And any of these generates enough torque at peak output to match half of my Harley Softail. No, they're not the same power, but for getting your HydroCycle going in the first place, torque seems to be the requirement. So--you'd have to carry 240 lbs of batteries to even consider one of these, but you'd get a few hours of quiet fun out of it. Let's say you had four group-29 deep cycle batteries from Sam's Club, which cost you $63 bucks each (oh, sure, I'd use AGM cells, but I'd need more of them) and weigh 61 pounds each. Add a brushless ETEK and a controller and some heavy cabling and a prop and shaft and now your powertrain weighs 285 pounds--but that's not bad in a PWC since you don't need any fuel. And you'll have 500 AH of power, but should use only half of that (deep cycle rule of thumb, again) so you can play for two and a half hours. And it all cost you about $1400 plus a dead PWC hull from somewhere. Hmmmmmm..... (oh--that's what the motor would sound like)

[tinhorn]

Man, I just gave away one PWC hull, and cut another up so it would fit in the dumpster.

[juiceclark]

A-Ha! So, I'm not so crazy. Dr.Shaddock's 300lb drivetrain weight was roughly what I had in my head. The design of that old HydroCycle is nice and wide and has a significant displacement for easy planing.
We had a series of fountains installed in a lake nearby with 8hp electric motors that throw some serious water...perhaps much more than necessary for propulsion. I never envisioned this to be a 70mph death trap like the new, hot-rodded jet-skis. Rather, a pleasant, economical and low maintenence form of casual transportion for people who live on the water like me.
A little bugger like this just posted in the gallery would make an interesting electric design as well:
http://www.boatdesign.net/gallery/sh...hp/photo/10441

...and by the way, I don't know about running an extension chord down to the beach but all three boats at my dock are plugged into shore power 100% of the time they're not at sea.

Tony in Sw FL

[drshaddock]

Tony, that's a really cute little hotrod you found. I'd really like to a see an electric version of that. But--as a confidence builder in the validity of your idea, check out this website: www.psnw.com/~jmrudholm/etekoutboard.html and be sure to follow from page as this guy develops his ideas. Basically what he's done is put an Etek motor (older version) onto an outboard lower drive unit and add batteries, then installed it in two different boats. What's nice about this guy's web pages is that he does some documentation and semi-scientific research. Not enough consistency or information to be truly valuable, but still it's neater than heck to see how this all works for him. Bear in mind he ends putting his motor onto a sneakbox, which is a displacement hull, not a planing hull--and he appears to be driving it beyond hull speed (he's managing over 10 mph when its weight is about 1400 pounds, by the way). But I was most intrigued by the fact he could manage a nice sedate 3.4 mph or so with only 20 amp draw--and with his batteries, he could probably maintain that all day and night. Not bad...

[juiceclark]

I restored a pair of 1970 vintage "Ski-Horse" PWCs. There were loads of fun. But the design of the hull was faulty; not wide enough and too much deadrise.
http://i246.photobucket.com/albums/g...k/IMG_0578.jpg

I nice wide platform would be great for a PWC with a modest, 25 or less mph top speed. With all that space a battery option seems quite plausible.
http://i246.photobucket.com/albums/g...IMG_0574_2.jpg

[sparky_wap]

Tony,

I am working on electrifying a row boat. Using two 6.5 HP PMDC motors and deep cycle batteries, my goal is 25 MPH on plane. Run time is limited to about 30 minutes on-plane but I am on a small lake.

I am working on some rudder issues now but it should be ready in a couple of weeks.

Joe

[alan white]

Great concept. The only problem is the batteries are very expensive. Also, (another problem, i guess), water friction disallows recharging upon braking like cars. The PWC will last only so long and must switch batteries just like a power tool.
Maybe coupled to a wind turbine, the boat would recharge during the week.

Alan

[tinhorn]

Couldn't you extend your battery charge by connecting narrow sidewheels to a generator? They could be hidden in the sides, or you could even mount one in the middle of the boat, hidden from view. I can't imagine the power loss to turn a generator or alternator would be that great.

[Rick Willoughby]

Originally Posted by juiceclark

I watched a program about the Tesla the other day - that's the electric sports car all the tree-huggers are all excited about. I guess it really does look better than a freakin' Prius! Anyway, the powercell in the Tesla is just a big box full of thousands of those lithium-ion, cigar-shaped cells...like you'd find in an electric screwdriver. They said it will do 150+mph...I wonder if it can for more than 50 feet without runnin' out of juice?

http://www.teslamotors.com/design/under_the_skin.php

To the point: I never liked PWCs because they are loud and obnoxious. But what if you created one with a thousand little waterproof slots for the batteries safe and dry in the hull? You could easily arrange an electric motor inline with the waterjet and have a nice, quiet and rechargable ride.

I really like the design of the Hydrocycle made in the late 1960s. I'm sure you could make it wide enough to put a thousand lithium ion batteries in the hull with plenty of displacement left for people. Hey! I'm just a financial consultant/dummy. You marine architect/engineer geniuses should get on this right away! (promise to send a check if you make $? You can add custom features and sell it to Harley-Davidson)

http://www.fiberglassics.com/hydrocy...yclebxx004.jpg

http://www.fiberglassics.com/hydrocy...yclebxx003.jpg

Tony in Sw FL

If you are going to pay serious money for a set of A123 lithium ion batteries you would not fart about with an 8ft long PWC. You would end up on your ear; possibly dead. These batteries have serious power density - the little AA cells have little voltage droop at 100A. A bank of batteries for a few hours use or the occasional drag run will set you back around USD10k to 20k.

The latest electric boat record attempt is targeting 130mph:
http://www.electricrecordteam.com/
They have set 68mph with old boat so I expect they will get well over 100mph with latest boat and they are only using VRLA gel or AGM type. I expect the boat to literally fly with Lithium ion.

The agni motors used for the record seem to be setting the standard in power to weight. They have an 84V motor able to put out almost 30HP peak and continuous of 24HP. It weighs 24lb.
http://www.agnimotors.com/143-47rpm84v.pdf
These are expensive motors. They will set you back around USD2000 without any controller.

Mars has brought out a new high torque brushed motor that is selling for around the USD500 mark - I believe it is also marketed as Etek -RT. It will pump out 19HP on a 72V battery for a couple of minutes. I think it also weighs around the 24lb mark.

I have just bought a pair of Mars brushless motors and Kelly controllers for USD1540.

Lithium ion batteries are the latest thing around the drag strips. There are not many Datsun 1200s that can lay down 11s quarter miles:
http://www.plasmaboyracing.com/videos.php
That's what happens if you have the money and inclination to fit a decent lithium ion battery and a well sorted drive train.

Rick W.

[Rick Willoughby]

Originally Posted by sparky_wap

Tony,

I am working on electrifying a row boat. Using two 6.5 HP PMDC motors and deep cycle batteries, my goal is 25 MPH on plane. Run time is limited to about 30 minutes on-plane but I am on a small lake.

I am working on some rudder issues now but it should be ready in a couple of weeks.

Joe

Joe
What motor and controller are you using?
Rick W.

[Rick Willoughby]

I have attached a drawing of the drive leg I am making for my Solar-Wind boat. This has a Mars BLDC motor, ZP3 3:1 gearbox and 470mm prop of my design. Design point is 10kts at 2700rpm and cruise of 7.5kts at 2030rpm with 1450W motor output. The motor and controller combination has an efficiency of 84%.

The drive leg will slot down into a well inside the cabin of the boat. I will be able to lift it out to inspect and for transport. It will weigh around 35 pounds.

I will only use the top flange on the gearbox for mounting to the shaft tube so I can cut of the protruding parts of the output shaft flanges as well as the other mounting holes. I will also fair around the box with epoxy/microbubble.

Rick W.

[sparky_wap]

Rick,

I am using a Navitas CTL 2021 48v, 450 A controller and two Leeson 6.5v PMDC motors through a chain drive to a single shaft. The (4) batteries are deep cycle marine rated size 29 rated for a cca of 875 amps and about 125 AH.

I have the next system in the design stage but might need a better hull for the propulsion system. It consists of (2) Prestolite Hyd. pump motors series wound and (2) Navitas 48v, 1000 amp controllers. Using my flooded batteries, I should be able to hold 30 HP for up to 30 seconds for a fast trip across the lake.

All proplusion items I purchased on EBAY used for a fraction of the retail cost. When I sarted the project, I knew little about marine propulsion. Now, I realize that I knew even less.

Joe