SailNet Community - View Single Post - Optimal propulsion system
View Single Post
  #58  
Old 10-15-2012
MedSailor's Avatar
MedSailor MedSailor is offline
Closet Powerboater
 
Join Date: Mar 2008
Location: Anacortes PNW
Posts: 2,461
Thanks: 71
Thanked 51 Times in 43 Posts
Rep Power: 7
MedSailor is on a distinguished road
Re: Optimal propulsion system

Quote:
Originally Posted by Stumble View Post
Julie,

Tesla is using lithium ion batteries last I looked. Figure an energy density on them of about 2% by weight compared to gas. So to replace a gallon of gas you would need roughly 325lbs of batteries. The Tesla battery pack weighs around 900lbs, so figure the energy equivalent of 3 gallons of diesel. And they aren't cheap, the battery pack which is good for a nominal 4 years cost roughly $36,000. So even assuming electricity is free it's going to cost you $8,500 a year in battery packs.

At today's fuel prices you would have to be doing a lot of motoring to come anywhere close to justifying it from a cost advantage.
To you good sir, I concede that you win this argument, and you will win for a LONG time to come. This isn't about just energy density and cost though. The cheapest way to get from point A to B on the water is by ferry. Next best, is powerboat. We can't possibly justify all the design and space losses of our sailboat hulls, the weight of our keels, and the massive expense of our rigs and sails compared with a simple small engine that can push us at displacement speed.

In fact, most of us already have that engine aboard but prefer to use our cost-ineffective method of propulsion (sails) even though they usually make us go slower, we can't pick our direction and they require constant attention. Curious isn't it? We crazy sailor types must like things in our propulsion systems besides cost and efficiency then. See my post a page back or so on motor-sailing and why we like electric.

MedSailor
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


I have a sauna on my boat, therefore I win.
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote Share with Facebook