Njawb

Batteries are only the weak link if you are talking about hybrid or pure electric drive. Hybrid doesn't make much sense for a boat, since the power usage profile is more constant than it is stop and start. Pure electric drive does have real problems with both the energy and power density of current battery technology.

If you are talking about electric motors turning prop shafts, however, you should be (as many in this thread have been) looking at diesel-electric systems, where there is no bulk energy storage in batteries, but rather the matching of diesel power to electric drive functions more like a transmission.

It's a sound and potentially efficient idea in principle, but making it work with off-the-shelf components in a smallish, fastish boat presents practical difficulties -- weight principally.

knockld

Kinetic to electric back to kinetic energy conversion is not efficient plus the wieight of the generator and motor. It works fine in cruise ships, diesel locomotives because in those applications you get rid of a huge clutch and the complexity of that. Also for the cruise ships they are 360 trainalbe without complex gears, u-joints, etc. For a power boat no real gain. For cars works well beacuse of the gain in efficiency in regeneration in braking. Might be a great idea for a slow cruiser with a small electric/solar combination with diesle/battery back-up. Could also be feasible when there is already a very large electrical demand or a very really powerful way to make electricity like a nuclear reactor (either direct or steam turbine electricity. For the current sub designs we still use steam turbines for propulsion. May change in the future not due to efficiency but radiated noise.

Njawb

Running an internal combustion marine prime mover at a more efficient operating point in an electric drive system can more than make up for those inefficiencies.

Here's how.

The weight penalty associated with diesel-electric systems is the major impediment to their use in go fast boats. It is not an insurmountable problem in bigger or slower vessels.

TopSpin80

www.feys.org uesd to be the domainl name of one that was built in texas. They use seimens watercooled AC motors. the webpage is no longer in service

Fast Electric Yacht Sales

Ernie

BradH

Ya got me interested....where can I find out more.

Little school project, 35 mph all electric, driving blue boat near lane:

http://people.cedarville.edu/stuorg/...l%20Sprint.wmv

glassdave

iTrader: (1)

Thats pretty cool, got any more pics? whats the story with the compitition.

BradH

World championship of solar-electric boat races, this June in Fayetteville Arkansas. www.solarsplash.com. Two races, 300 meter sprint and four hour endurance. Any motor/drive system, power limited to 36 volts, battery weight of 100 lbs.

We last ran this boat in 2005, won the sprint finals. Katrina kinda messed up the boat, as we are in New Orleans. Just getting everything back together to race this year.

First pic testing, second is the motor/drive assembly, third is the hull. Fully trimmable and steerable surface drive, drains 3 12 volt batteries in about 30 seconds. No speed control, just on-off switch.

tomcat

Check this out. I saw this a year ago and got the facts a bit jumbled; still interesting.

http://www.seattleoutboard.org/electric.html

TopSpin80

a few of the naval architects I work with went to UNO.
cool project

Ernie

offshoresteve

If I remember correctly the yacht "Limitless" has diesel electric propuslion.The yacht is 300'+ and the first 100' is the engine room