Magnetic Drive

[Ukeluthier]

Originally Posted by zerompg

Wouldn't this just replace the sail drive and motor in one step?



I drive a Nissan Leaf hence moving to all electric is more a shift in mindset than impossible.

You still have a big, honkin' hull penetration, which is what the OP was trying to avoid.

It still would make more sense to me to just glass the rim-drive unit into the skeg or rudder and provide the juice via a diesel.

[Nicholson58]

Originally Posted by jongleur

Somebody in another thread mentioned the necessity
of a shaft through the hull for an engine.

Has anyone attempted to build a neodymium magnetic
drive coupling? They are damn strong magnets. One on
the inside and one on the outside. No hole.

Comments?

We (and probably many or you) have these on small magnetically isolated pumps. I have at least 6 on board. They are not practical for large power transmission and are insanely expensive.

[beiland]

Originally Posted by zerompg

Wouldn't this just replace the sail drive and motor in one step?



I drive a Nissan Leaf hence moving to all electric is more a shift in mindset than impossible.

What was the name of that unit, if you recall??
...and/or a weblink in english were it might be found??

[beiland]

I've been a fan of these rim drive units for some considerable time,...and as propulsion units rather than just (bow) thrusters.
Section 8 and Rim Drives

http://www.runningtideyachts.com/dynarig/index.php
Rim-Driven Propellers: Instead of propulsion blades being attached to a central hub and propeller shaft, they are rooted to the rotating inner rim of a circular nozzle type unit. The rim is electrically driven with a permanent magnet motor, where the motor windings are in the stator and where the rotor has a number of permanent magnets. The electric motor is an integral part of the 'propeller nozzle'. These units are cutting edge technology. First came the rim-driven thrusters, and very soon the rim-driven propulsers. There are lots of pluses to recommend this new technology:

• Smaller diameter than prop counterpart at equal power densities
• Can be tucked close under the hull skin for less draft and more keel protection
• No constraints as to location as with shafted props…can be located forward,…away from transom pitching
• Rim-drive unit can be contained in its own 'waterbox', & accessible, & serviceable without hauling the vessel
• Waterbox mounting would allow for partial retractability in shallow waters…full retraction under sail.
• Less noisy
• Less susceptible to fouling lines
• Potentially safer for divers and marine life
• No reduction and direction gearboxes required, instant fwd/reverse !!
• Phenomenal maneuverability, joy-stick operable (gamefishing plus, plus)
• Exciting New EPS Thruster (& Propulsion) - Boat Design Forums

I was hoping we would be much further along with the technology by now, but I think the world wide pleasure boat market 'depression' since 2008 has held things back considerable.

Exciting New EPS Thruster (& Propulsion)
Exciting New EPS Thruster (& Propulsion) - Boat Design Forums

[beiland]

Originally Posted by Ukeluthier

While pure electrical propulsion isn't ready for prime time in cruising boats mainly due to limitations in battery technology, there is no such limitation for diesel/electric hybrids that don't rely on a huge battery bank. A big advantage would be that the unit could be driven from either the main propulsion diesel or a genset.

As to attachment, the logical approach for a fiberglass boat would be to have the housing molded as a unit with the skeg or whatever part of the boat is the logical mounting point. The electrical lines could then be all internal.

Not saying that such an installation wouldn't require some outside-the-box thinking or very sound engineering, but it appears do-able and more practical than a magnetic drive with a conventional prop.

Maybe something like this?





Sea Jet's RIMJET, Advanced Electric Ship Demonstrator

[jongleur]

hp"]Section 8 and Rim Drives[/URL]

I like it. Thanks.

[beiland]

I thought these were nice features also..

• Rim-drive unit can be contained in its own 'waterbox', & accessible, & serviceable without hauling the vessel
• Waterbox mounting would allow for partial retractability in shallow waters…full retraction under sail

[beiland]

Originally Posted by zerompg

Wouldn't this just replace the sail drive and motor in one step?

Can't seem to find that unit? Perhaps it was some product by
http://rotorque-jet.de/defaultsite
but that link goes to a default page.

I did just find this reference on another forum
360 rotate sail drive - Boat Design Forums

They refer to it as a Torque-jet unit,...apparently from Germany,...and possible still in development, although it appears that company website has been taken down,...and the utube presentation along with it.