Electric Kayak

[dontsendbubbamail]

Jermey,

Is this light enough??



http://gaboats.com/

Bubba

 

[dontsendbubbamail]

I think I am sold on the idea of a removable twin hull.

The SPK1 is the coolest thing I have ever seen. I went to their website but they don't seem to have too much information on it. With 36lb of thrust, how fast can the kayak go and for how long? Do the solar panels charge the battery continuously? Where can I find more information about it? It really looks like a great bargain.

Here is a data point for you. I have been running a 17 lb thrust trolling motor on an 18' canoe with a 12v marine deep cycle battery. My estimate is that my max speed is about 5mph based on watching the tree go by. Six hours of run time for an outing on the river and I have not run the battery flat.

Bubba

 

[paultrafalgar]

Thanks for leading me to Heat-Shrink Dacron. What a wonderful material to construct a Velomobile with!
Chicken wire former - Spread over Dacron - Heat Shrink.
Marvellous!

 

[Jeremy Harris]

I really love the look of those GA boats, but can't help but think they might be a bit fragile - certainly light though.

I've got a lot of experience of using heat-shrunk Dacron on home-built aeroplanes. The stuff goes under the trade names Stits Polyfiber or Ceconite, both are the same, and it's available in various weights.

For a velo, I'd go for the lightest weight cloth, sold for ultralights. You won't get away with just putting this over chicken wire, though, as it exerts a lot of pull on the frame as it shrinks. Also, you need fairly large bond areas around the edges to fix the fabric to before you shrink it to fit. When designing wings for fabric covering we often have to stiffen up the trailing edge strips to avoid the fabric pulling them inwards as it shrinks.

There's lots of good stuff on using Stits Polyfiber/Ceconite, a quick Google on these names will find a few. Although you need to use the proper adhesive to stick the fabric to the frame, you can same a fair bit of money by sealing the fabric with emulsion paint (latex paint for our US friends), rather than use the expensive system finishes from the fabric suppliers. Pretty much any sort of top coat works, although it's best to go for something flexible. I've used 2K polyurethane gloss finishes to good effect on "showroom finish" jobs, looks good, but can be a real pain to repair if it gets holed.

A good plan for a velo frame might be to build a frame from light, bent spruce spars, something around 1/2" square would probably be about right, maybe smaller. Something like an airship shape would be easy to build and cover.

Jeremy

 

[12p3phPMDC]

I love the idea of powerering a kayak or canoe.

I keep thinking about a 6 kw jet drive
using a Tesla pump as the jet drive.

Also love the idea of a velomobile with an aircraft like frame covered in
a shrunken skin....

Here's a nice and simple low power Tesla pump.

[youtube]http://www.youtube.com/watch?v=ordrp4KXEKQ[/youtube]

http://www.youtube.com/watch?v=ordrp4KXEKQ

 

[Kurt]

Having done a few initial sums, it seems that you don't need much power to drive a light canoe - 70 watts or so seems a typical cruise power for around 4 to 5mph. Even a small lithium battery will provide a fair endurance at this sort of power level.

What usually sucks the power in land based EV's is is climbing hills and wind drag at speed. I know on my electric bike when you have a nice dead flat section and you just motor along at a modest speed. A very little amount of wattage can go a long way.

With a kayak on the open water you defiantly wont be climbing hills unless you plan on going upstream on some fast flowing mountain river its going to be dead flat travel . Your typical kayak speed and your position in the water wind drag wont be an issue. You just have the displacement and friction or the water to deal with. Not sure how this stacks up in comparison to the tyre drag encountered on a bike.

If your sums are correct . 70w and 5mph my own 20ah 36v headway lifpo4 battery would last for around 10hrs and you could travel for 50 miles. Sounds to good to be true :? Anyhow I have to get a kayak first before I can start this project. Scouting about until something nice second-hand comes up.

kurt.

 

[Anonymous]

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[Lock]

Uhhh... yer tapping about HDPE? Is there a recycling mark on the plastic? A number enclosed in a triangle (eg "1"?)
tks
loC

 

[www.evlogix.com]

In water especially, slower speeds has a huge impact on range. You might actually see 3-4 times as much distance at 3 mph as opposed to double that, 6 mph, which isn't necessarily true for land vehicles. You tend to have to get above 15 mph for that relationship to start becoming apparent.

 

[velowatt]

Many tandem kayaks use a rudder to help steer, this is usually operated by the rear cockpit using foot pedals. The person in the back seat therefor usually has responsibility for direction control, but it does not matter whether the stronger paddler is in front or back. In our tandem kayak, my wife usually sits in back and steers while I am in front. I am bigger and and stronger (although she can really paddle), more weight in the front does not affect handling of the boat. We have found this arrangement to work best for us- especially if we want to go fast! (Boat is a Necky tandem- plastic construction).

 

[Jay64]

I have found that if both passengers are at least decent paddlers, then it doesn't really matter where the stronger one sits. However, if one person is drastically weaker at paddling, then usually it is better to have the stronger in the back. If the weaker paddler is in the back and can't keep up with the steering requirements, you can get in a bit of trouble.

I never even thought of putting a motor on my kayak. This thread has given yet another project. :lol:

 

[etard]

Have you guys seen this Kayak?

http://www.nativewatercraft.com/mariner_12_propel.cfm

I think it uses a worm drive though, so efficiency is not gonna be good.

 

[vax]

I happen to have big (5.5 x 0.8m) canoe mould for fiberglass.
The plan is to make 2 hulls, connected by sleek plywood cabin. Car seats inside for comfort and all.
Also I want to make my own "trolling motors" from 7kw Turnigy motors. I can access some machinery, lathe etc. so I can make my own motor housings, material would be probably POM plastic. Propellers are from old outboard.
Other ideas include using windmill besides batteries and OpenCPN software for navigating/autopilot.

 

[monkeybutt]

@ Kurt'
I don't know if this is something you are still considering,if it is don't discount wind. Although you will not be travelling fast enough to encounter similar resistance to that of a bicycle,even relatively light winds reek havoc on light weight,low displacement watercraft.
I have spent far to many hours paddling against headwinds and now plan extra days on a trip to wait out the wind. I would suggest paddling as many kayaks as you can before considering a purchase as they can be as different as a child's tricycle and a fine road bike. I have never been turned down a test ride by a kayak shop (provided they were near the water) and most of us who paddle rotomolded yaks are happy to let a newcomer take are boats for a spin as they are virtually indestructible. Hope this helps. Rob.

 

[Kurt]

I ended up with a BIC Trinidad sit on top kayak. Strong and very stable recreational fishing kayak. Its a 2+1 style 2 adults + one child . The kayak is designed to have a small trolling motor fitted to one side on a bracket. I made my own mount that fits to the factory mounting locations. I have had it a couple of years now and at first a purchased two electric trolling motors. the first one was a 40lb thrust but a little heavy and that kind of thrust- torque isn't necessary on a light kayak. Thrust didn't relate to speed just torque. The second one is a tiny 18lb thrust motor. I use the little motor as its light and simple. Perfect size for a kayak.

last weekend I managed to get a watt meter on the motor and record some date with GPS.

The motor settles in a 155w at 12.5A running of a 60ah 12V SLA . The speed is around 4.5kmh and peek of 5kmh That's with two adults and one child. I did a few km around the lake and used about 16ah from the battery.

This speed is fine for fishing and trolling and just putting around and at times paddling along with it. But at only 155w you cant expect a thrill ride. Even my wife said she would be happy if I could make it faster. I started thinking about my Turnigy 80-100 and 15s lipo actually 48v life would be more practical at 3000w that's 20 times the power of what I am running now .

Ok so seriously I would love to have the power to get this thing really moving but also have the option to put along at 5kmh and get some distance out of the battery. My thoughts are to buy a very small ICE outboard motor. Perhaps a cheap 2hp with a broken engine and just use the 90 deg drive shaft and prop. My thoughts are the little 2hp ICE engine would be spinning at say 6,000rpm max so would be perfect for a direct replacement for a largish out runner rc motor with halls and a little 12 fet controller. the weight should be low and I can mount the outboard centred at the rear of the Kayak with peddle staring control or a servo control steering.

This little 2hp honda 4 stroke is only 12kg. Given it has a 60cc engine up top I would say a good 6kg of that is the motor.The fact its air cooled and has no water pumps ect keeps the design simple.The only issue would be finding one with a stuffed engine, being a Honda 4 stroke they last for ever . Anyhow I am on the lookout.

Kurt

Short video taken on the lake, sorry about my 4yo daughter rambling on in the back ground.
[youtube]F_X8LxljGUo[/youtube]