The rise of electric Boats

[valhalla360]

Originally Posted by Narfi

Well..... the smart money would be to store the boat for a year and buy a mid range loop boat and sell it when done and move back 'home' onto the catamaran.

Cheaper, less hastle setting up, less hassle masting and demasting, less depreciation, etc.... adventure of a new home/boat and all the quirks that come with it...... can go up the Rideau, trent/severn, etc....

Disadvantage is we don't get to live in our own home and space and cant keep an eye on it for a year......

I was thinking along the lines of a 20kw generator, you think 10 would be enough? I feel there needs to be a safety 'reserve' somewhere, and when you don't have overpowered diesels, and you cant practically carry enough batteries, an oversized generator is the only way to achieve a safety 'reserve' ?

Alternatively I suppose plan on running the smaller generator anytime the battery bank hits 50% and keep that as your reserve, that means you wont maximize your solar use, but it would let you keep a lighter/cheaper generator.

A separate boat would be more expensive than just using the existing cats diesels and going. If you don't want to worry about the mast, just pull it before the start and store it. It's really not that hard.

I was working under the assumption that there was a goal to utilize some significant degree of electric power for propulsion.

Assuming 20kw of propulsion is sufficient for a nice cruise speed (and the motors are upsized beyond that for emergency work) and you have say 90kwh in the battery bank (with 80kwh usable):
- For short runs (under 4hr), just go off battery.
- For long runs, crank up the generator right away. With 10kw being fed into the battery bank, the battery bank will only drain at 10kwh per hour giving you 8hr with 20kw feeding the motors. After that it drops back to a limp mode of 10kw for propulsion but a bigger cat might have a 7-8kt cruise speed, so 8hr is 56-64nm which will accommodate all but 2-3 daily runs on the loop. (This gives you an hour at 20kw from the remaining battery bank power)
- For really long runs, you may want to run the motors at a reduced output to extend range rather than run the batteries to your lower limit and go into limp mode. You would have to play around to see the real life performance to decide which would be better.

Between 30-50nm runs, you could hold off starting the generator to see how the efficiency on that run is doing (strong headwind, start the generator early, strong tail wind, you might get 40miles off the battery)