gas to e conversion

[Yoda-O-theNorth]

I have 75 hp on a 15 ft bass boat. like the idea but what about runtime and cost?
http://youtu.be/eX95hdSm_XY

[Evoforce]

Great video! Boats are less efficient then automobiles. It all depends on the speed and range that you plan on traveling. Plan on a big battery bank!

[Lock]

I have 75 hp on a 15 ft bass boat. like the idea but what about runtime and cost?
http://youtu.be/eX95hdSm_XY

What gas consumption do you usually expect? You can estimate Wh/mile etc from this to get the total Wh size of pack you need for X amount of run time. The electrics might be about 2x more efficient... so needing 1/2 Wh/mile you see presently. But a lotta variables.

[Xanda2260]

Electric drive on boats can be very efficient (although an electric outboard is less so due to the drive train). This is due to the large torque at low revs of motors. This means you can run a big prop at low rpms instead of a little prop a high rpm. That setup is far more efficient at transfering energy to the water than the typical gas setup.
You wont need anything like 75hp to get the same performance. I dont know what your hull is like, but a decent displacement hull (like a yacht) can do 4-5knts on 1kw (1.3 hp). As your boat is only 15ft long, hull speed wont be very fast. What speed do you need to do? Of course I'm assuming a displacement hull. If you have a planing or semi-displacement hull, power requirements become a lot higher, with correspondingly larger battery packs needed.
Defo need more info on your boat amd requirements. Pics would be good.

Hopefully Jeremy Harris will pop in at some point. That guy has forgotten more about electric boats than I ever knew...

[Yoda-O-theNorth]

Ive been getting about 30 mph 2- 6 gallon tanks. Its a 1977 trihull. Im new to e-anything and just wondering what it would take to convert

[Hillhater]

Bass boats are fast planing hulls.
If you want to replicate that 30 mph performance for any distance, you will need a lot of power and battery's.
I would suggest it would be impractical from a cost point of view.

[Jeremy Harris]

Planing hulls are a problem for electric power, if you want a reasonable operating time. Power to propel a boat goes up roughly as the cube of speed, so doubling the speed needs eight times more power. At displacement speeds (below what is often called "hull speed", which is very roughly 1.4 x square root of the waterline length in feet, with the speed in knots) then the power levels are quite low. For example, my pretty lightweight 17 ft boat uses around 100 to 120 watts to cruise at about 3.5 kts. To make my boat do 7 kts I'd need a bit under 1 kW, to do 14 kts I'd need maybe 8 kW. In terms of battery current, my boat runs at around 8 A normally, at 7 kts it'd draw about 64 A, at 14 kt it'd draw well over 500 A. This illustrates pretty well how power-hungry boats can get as speed rises.

You can gain a fair bit of efficiency by exploiting the high torque capability of an electric motor to drive a large diameter prop at a lower rpm. The efficiency gain is pretty good, so less power is needed than if it was a smaller prop turning faster. The big practical problem with this is that a big prop increases the boat draught, plus may suffer from weed and garbage entanglement to a greater extent. Both of these problems can be a real limitation if you mainly operate on inland waters where weed and shallows may be commonplace.

If you want a long run time using electric power then the only real way to go at the moment is a slow boat with an easily driven hull shape, something that's long and narrow, with no dragging transom at the stern, is pretty much ideal. It's pretty easy to build a boat like this that will run all day on a charge, provided you can accept running at maybe 4 or 5 kts rather than 20.

[Xanda2260]

Maybe diesel electric?

With a trihull, and that speed, I dont think electric will work out well. Unless you have VERY deep pockets (like several 10s of thousands of dollars), in which case you could just buy a boat withh better characteristics for electrifying.

Sorry dude

[Yoda-O-theNorth]

Thank you all for the responses. Big project for first timer. May try the canoe. I have extra tm's