On Sun, 9 Nov 2003 00:35:06 -0800, "Evan Gatehouse"
wrote:


"Glenn Ashmore" wrote in message
news:JDPqb.10756$62.1728@lakeread04...
I don't think it is quite ready for prime time yet but here is an
interesting idea. A small retractable Voith-Schneider drive like those
used on modern tugs. Retracts flat into the hull and when extended will
deliver thrust in any direction. http://www.spw-gmbh.de/en/hb/

Wow. I'm not a great fan of VS drives ('cause they have lower efficiency
than ducted props) and they are hideously expensive. I'm surprised he has
got around the VS patents!

The new Volvo 70 rule allows for retractable propulsion systems - using a
Volvo engine and shaft drive. Not sure how designers will make this work
but it will be interesting to see if can trickle down to more mainstream
designs. Now I want to sit down with a sketch pad and start thinking about
this!!

I have long thought that a vertical saildrive could be made in a
retractable form. A non-folding prop could be keyed so it could be
gotten vertical from inside, and the whole thing lifted through a
tubular well. A diisk on the bottom could retract into th ewell far
enough to allow a faired surface to fit the particular hull to be
added with microballoons and epoxy.

It could be made in azimuthing form, but that would add a lot to the
price.

It couldn't be ducted without makig the well much larger, but for a
sailboat efficency isn't as important as getting out of the way.

I believe it would come down to which is cheaper, if they both take up
as much room inside.

We don't really know if he has gotten around the VS patents, do we?
They may just not have noticed him, or don't feel threatened.




Rodney Myrvaagnes NYC

Let's Put the XXX back in Xmas