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Electric Propulsion

The greatest idea to date, or is it? 

Just like everyone who first heard the news, my eyes lit up too. I am a sailor, and as one, I hate hearing that engine noise.

So, I dug in and investigated the matter for years. So far, no matter how much I wanted to buy into this, I couldn’t make the move. Believe me, I had many opportunities to bite. You see, being an installer, I am exposed to view clients' good and bad decisions 😊.

 

Before I expand on that, I want to say this: I am writing this negative view-ish while thinking of blue water travel (long distance) in mind.

It does work for Duffy boats, bay sailors, and the like just fine, although I am surprised it took Duffy boats a long time to start selling them with a lithium battery bank or with solar roof racks. It may also work for super-fast sailboats (like the ones that can sail faster than the wind and recharge).

I do get it; they are quiet and small, but they are not yet able to work with the restrictions us sailors have. For me, the top two restrictions are space and the ability to recharge. I watched Sailing Uma (YouTube channel), and I'm sorry, 8 hours of run time isn’t going to cut it when sailing long distance. And I know that in their case, they did sail far but not by pushing water spinning that propeller. Anyone who did the Baja Bash, for example, knows that if I told him he can get 8 hours on the propeller every 48 hours, he would probably not leave the dock unless an eclipse-like wind forecast comes his way.

Here is why, and these are rough numbers: The electric motor needs 48 volts DC to push an average size 45-footer sailboat at 6.5 knots. That is usually the voltage they run on.

Now you are asking it to flow about 200 – 300 amps through that conductor. Say you did that; the average battery bank for this size with an electric motor in mind is about 600Ah. Since you can use about 80% of that without hurting the batteries it leaves you with 480Ah, which means you will have juice for maybe 2 hours!

Without a generator, it will take you a lot of time to recharge this. Say you have an e-motor with regeneration propeller technology, a huge solar array, and several wind generators. It still might take you a full day. And if you plan to run a generator, then you are basically cheating because you will burn diesel for say 4.5 hours even with a fast charger to recharge the bank just to give you another 2 hours of run-quit time.

So far, I have installed some and they loved it but I also removed some, the last one I removed was nice but the owner didn’t understand the sacrifice he made when he bought that e-motor and it was sad to see him throw away that bad experimentation money away.

I wish we were there; I'm hopeful for the future, lithium battery power density is improving, and so is solar efficiency. I welcome these innovations with open arms. The day I won't have to hear that motor ever again when I go sailing long distance will be one for the books, and by that, I mean the logbook 😊.








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