Electric Motor Propulsion for 40 foot sailing catamaran
...ltr I recently sent to a few Euro manufacturers/developers of small scale electric drive systems for vessels.
Electric Motor Propulsion for 40 foot sailing catamaran
Dear Sirs,
I am working on a design for a 35-40 foot catamaran that I term a picnic/weekender catamaran. The concept will be somewhat similar to this one I found in Thailand a few years ago. I posted it on several boating forums a few years ago.
http://www.yachtforums.com/threads/weekender-picnic-powercat.13966/#post-173670
This particular catamaran was a powercat. I will be adding a sailing rig to it. I will also adding a trolling/fishing chair area to rear deck area,... so that pictured Zodiac dinghy will be relocated, and the two outboard engines need to be eliminated.
I need to repower this cat design, both for close quarters docking situations, and for some motor/sailing situations.
I have had a very long time interest in the rim-drive propulsion concept.
What I have in mind at this moment is how I might adapt this
Vetus Rim Drive unit to be my single primary propulsion propeller. I would like to mount it in the aft portion of a of the wingdeck of the vessel, and make it steerable upon demand, and also retractable when sailing. Naturally it requires an electrical supply, which as I understand it under present technology can come from a combination of battery power and a relatively small DE power plant. This power plant would be located in its own insulated (heat and sound) box up on the flat deck of the catamaran.
So here are a list of questions I have at the moment:
1) Can such a rim-drive propulsor be run continuous without overheating? It is my understanding that the Vetus unit can do that now.
2) Whether it is the Vetus rim-drive, or another electric drive motor, is it possible to operate such a 'DE system' with very little battery supplements?
3) How few batteries are required (in the interest to keep added weight down) ?
4) Is it possible to 'direct drive' this 'electric prop' with the DE power plant, or are batteries required.
5) I realize Vetus has its own DE power plant, but it appears that FisherPanda has an even greater selection of small DE power plants. Can these systems be mixed?
7) Should the Vetus rimdrive prove not powerful enough, what are the other alternatives that anyone would suggest??
As an example of why I might be considering this approach, I will offer this personal experience of mine. I was the original importer to the USA of French catamaran line,... the original model was a 37 foot boat called the Louisiane 37. I placed a 9,9 hp Yamaha 4 stroke Hi-Thrust outboard engine on it. It was a limited production outboard they made with an extra gear reduction in the output prop shaft so it could turn a bigger propeller. It worked pretty good as we got 7 knots out of the vessel in calm conditions. The engine was mounted in the center on a rear beam of the vessel, and soft lines were lead from the engine to the rudder arms so when docking the engine would steer along with the rudders. Maneuverability was VERY good. It made me a believer in 'steerable engine', verses twins,...an alternative to consider.