This Sunday, November 10th, it will be 44 years since the sinking of the Edmund Fitzgerald... 2

[JohnRBaker]

The Edmund Fitzgerald's propeller was 19.5 feet in diameter, and the ship's maximum speed was 14 knots.

John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

 

[itsmoked]

Not bad. I looked around and it seems that's still a pretty respectable diameter for a ship's prop.

I found some other interesting things in the process. One a different type of prop called a cycloidal propeller.

And the other cool thing is they are now 3D printing ships propellers with wire welders.

[URL unfurl="true"]https://spare-parts-3d.com/2017/12/07/damen-unveils-3d-printed-ship-propeller-certified/[/url]

And

Keith Cress
kcress -

http://www.flaminsystems.com

 

[thebard3]

I read the book by Robert Ballard about his search for the Titanic (and Scorpion, disguised). The research vessel from Woods Hole had cycloidal propellers which were excellent for station-keeping and slow speed search patterns during the times submersibles were deployed.

Brad Waybright

It's all okay as long as it's okay.

 

[zeusfaber]

@itsmoked,

You've probably been hauled around by cycloidal propulsors without even knowing it. Lots of ferries - especially the ones on short passages that are double-ended and will go equally happily in either direction - use a pair of Voiths for propulsion.

A

 

[itsmoked]

Had no idea! I don't actually see how a cycloidal can work. Seems rather like a centrifugal pump impeller that's missing the volute.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[JohnRBaker]

The blades are not stationary relative to the axis of the 'propeller', as seen in this video:

https://www.youtube.com/watch?v=Ub563Yc3xls

John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

 

[itsmoked]

Oh wow.. That's pretty crazy. Not at all what I was envisioning, but seeing a movie of it, it makes total sense. Essentially they "generate lift" on the side they want to move towards. Very clever.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[Alistair_Heaton]

there is a few of these omnidirectional props.

I have been under a ferry in Scotland that was coming off a pier giving it plenty of wellie.

Its a bit bizarre to say the least watching the cavitation coming off with the direction of thrust. The ferry had two of them forward and aft completely independent so could spin on a penny. And also hold position 2 cm off a pier with no ropes attached.