Submarines have shafts for rudder and propellors that have to pierce the hull in order to go from the motor inside to the actuated part outside. As the hull has to withstand pressure, this creates considerable constructional challenges
With the rise of civilian electrical subs, this might be avoided, by installing coils in the hull of the sub, to transfer the power outside, to the actuated parts. The propellors would be replaced by Voith-Schneider rotors on both sides of the craft thereby expanding the maneuverability. Voith Shneider rotors, apart from superior power translation, have the benefit, in this scheme, of broad areas flush with the hull, which would be beneficial to the magnetic drive. Voith Schneider -type rotors normally suffer from sealing issues, even in surface-craft, which would also be avoided, as there would be no material link to the inside. Bearings holding the rotor can be fixrd to the outside of the craft.
This only works for civilian craft in terms of detectability and power (i hope).-- loonquawl, Feb 11 2009 Voith Schneider Rotors http://www.voithtur...ine_vspropeller.htmRotors with radial, not axial (as in propellors) power translation [loonquawl, Feb 11 2009] For the Germanically-challenged http://www.voithtur...ine_vspropeller.htm [coprocephalous, Feb 11 2009] Voith Schneider Propeller at wikipedia.org http://en.wikipedia...Schneider_Propeller [phoenix, Feb 14 2009] why would the funny rotors be required --- sherley would have made the hull long and thin at one end and stuck a conventional rotor to it...-- madness, Feb 11 2009 Sherley (who is he/she?) could of course mount a propeller onto the sub, provided it had enough magnetically active area compared to the thrust producing area - so in the long-and-lean hull design, this might be a ring with stubby propellor blades, or two of them countering each others rotation.-- loonquawl, Feb 13 2009 Constructional?-- phoenix, Feb 14 2009 //Constructional?// Pertaining to construction? The hole in the hull is bad for stability and needs quite some effort to not let in water...-- loonquawl, Feb 14 2009 random, halfbakery