Wednesday, February 17, 2010

Re: [Electric Boats] Going Electric On a Catalina 30 Sailboat

 

Randy,

I converted my Catalina 30, Kapowai, to electric with outstanding results.

Here is what I used:

Mars Brushless Permanent Magnet 28 turn AC motor
Browning Gearbox
drop pan mount with 4 motor mounts
Sevcon Gen 4 controller
Clearview display (shows all relevant operating data and battery state of charge)
flexible coupling   (protects the thrust bearing in the gearbox from any misalignment issues)
Electronic throttle, friction hold with center detente
ACME  12.5 x 14 propeller
4 -  8D AGM batteries  (underneath the aft bunk where the gas tank was)
4 - 4D AGM batteries   ( underneath the starboard settee)
1 - 8D house battery.

The boat is balanced on her waterline and the decks drain better with the batteries in this location.   Catalina 30's naturally list to port, so locating the 4D's on the starboard side helps balance the boat out.    Water can also sit on the decks which is alleviated by placing the 8D's under the aft berth.

2 Promariner Quad chargers  (every battery is independently charged and the battery bank is balanced every time it is recharged)    

At 5 knots she draws 3.6 KW and has a 20 nautical mile bias
At 4 knots she draws 1.3 KW and has a 40 nautical mile bias
At 3 knots she draws 588 watts and has an 80 nautical mile bias.

Better battery technology exists today so these bias numbers can improve.

I define bias as the amount of energy required to push the boat in calm conditions with no wind and no waves.    This establishes a baseline.   Range is different because rarely do we have no wind and no waves.


The additional weight of the batteries improves the sailing characteristics of the boat.   Catalina 30's are light for their beam, so sitting them down an inch in the water and adding the extra weight gives directional stability while under way.   The boat does not get moved around so much by waves.


I think of an electric sailboat as a better sailboat.   When you notice your sails luffing you can add power to the propeller and take away the luff.  (it is fun guessing how much power is required to fill out the sails!)      The magic in this system is the high efficiencies at low power.   Less than 100 watts negates the propeller drag and gives you an additional 1 knot of boat speed.    Add another 100 watts and you create apparent wind and fill out your sails.   You always have instant power on demand for coming about, staying in the wind to raise or lower sails or collision avoidance.   Electric boats are better in every regard except intermediate range where a diesel is better.    But how many people need more range than what electric can provide and who wants diesel on their sailboat anyway?    You can additionally supplement your energy resource with a  410 watt solar array.    The boat does regenerate at 100 - 120 watts at 5 knots boat speed.    


Gearbox noise is barely noticeable because we slowed the system down with the 28 turn motor and huge, slow turning propeller.    



You can see more on this installation at the following website addresses:




I have included test results and theory of operation on these links:




My hometown is Guelph, Ontario and I travel there once a year so I would be able to look in on your installation and give you hints and tips, though you can most likely do the installation yourself.   We have designed the system to be a drop in replacement on the existing engine bed.   

I would be happy to quote you a system price.   Please let me know what your range / bias requirements are. 


Regards,


James  

Propulsion Marine   







On Feb 17, 2010, at 8:40 AM, Randy Boyd wrote:

 

I have been watching this forum for a little while and am interested in what is involved in converting my diesel powered sailboat to electric. This is a boat that weighs 10,200lbs, full keel sailboat. Has anyone done this boat before and can I see pictures somewhere. Pitfalls, what would you do different if you did it again. I primarily use my engine for manuevering but at times motorsail to reach a destination. Thanks for all the information I have already read on this forum.

Randy,
83 Cat 30 SRFK
Hull # 3357
"Effen"
Toronto, Ontario






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