Electric Machines

[Boatsie]

https://www.electricmotorsport.com/e...or-24-96v.html

I found this quickly. At 35 pounds the weight isn't much. Add 2 dog type clutches and a reduction cog to shaft. Total weight could be less than 100 lbs and electric machine assembly could be easily disengaged from the propulsion system if the normal diesel is required. Or kept engaged if normal diesel is to be used to rapidly charge the bank.
4 batteries should last an hour if kept charged at marina.

I'm holding thought although I'm probably a loser with such thought yet depending upon the vessel it could be an easy fitment that provides a rapid charger at sea and less diesel use in a cove or... Most likely useless and an extra expense!
Now's a waiting time here and I like that idea.
Thanks everyone.. Every boat's different.

[Boatsie]

Doesn't think through well (just in case I spurred someone).
High currents. High currents kill. Volts not so much. Yet high currents and water. Ouch.
Also reducing lifespan of battery. Like the difference between driving the car to red line everywhere or just putting along (I know 'Henry D' had 2 massive batteries that were from the local oil refinery and had been used to power the refinery complex during events such as a black out. Short span high current until generators kicked in. Dad bought them because they failed current draw yet were fine on a boat where their wasn't a high current draw. Eg. Their life span was extended a further 4 years or more.
Having batteries banked in series could be a pain too. If 1 fails you lose use of all 4 (48v instead of 12v) hence avoiding high horsepower electrical systems wouldn't require the higher potential (voltage) to reduce current. Current kills.

I'm out

[stormalong]

Electric may work fine for day sailing but doesn't work for cruising.


Issues:

There is far more energy in diesel fuel than in batteries.

A dedicated, high voltage battery bank would be necessary to be anywhere near practical, just like electric vehicles.

Any long distance powering by electric would require an internal combustion engine driven generator to power it.


I visited a catamaran with electric propulsion some years ago. It had a big diesel engine driven generator to get range from the electric drive. The added complexity is just not practical.

[Head Sail]

Originally Posted by Boatsie

Doesn't think through well (just in case I spurred someone).
High currents. High currents kill. Volts not so much. Yet high currents and water. Ouch.
Also reducing lifespan of battery. Like the difference between driving the car to red line everywhere or just putting along (I know 'Henry D' had 2 massive batteries that were from the local oil refinery and had been used to power the refinery complex during events such as a black out. Short span high current until generators kicked in. Dad bought them because they failed current draw yet were fine on a boat where their wasn't a high current draw. Eg. Their life span was extended a further 4 years or more.
Having batteries banked in series could be a pain too. If 1 fails you lose use of all 4 (48v instead of 12v) hence avoiding high horsepower electrical systems wouldn't require the higher potential (voltage) to reduce current. Current kills.

I'm out

Big enough batteries is the problem. You might consider buying a Tesla, bolt it down to the foredeck of that 40 footer and attach paddle wheels.