Freak Propeller! The 'De Bay Propeller' from 1876

A booklet proposing a new propeller design in 1876 - the 'De Bay' Propeller -was recently discovered in the archives of the Lloyds Register Foundation. Of a very unusual design this animation shows how the De bay propeller worked.
It consisted of two screws, one with four and one with five blades. Portions of each blade were cut out.The Screws were fixed on two shafts - one tubular and one solid which allowed the screws to revolve in opposite directions, the solid portions of each blade passing through the gaps cut out in the other. The design was intended to make the propeller more efficient by forcing water directly backwards, in line with the keel.
Initial trials proved Mr DeBay’s claims. Ships fitted with the propeller were swift, handled well, made huge savings in fuel, created no side-wash and little vibration. But this innovation has long been forgotten by history.
For a full audio podcast on the history of the marine propeller check out the Mariner's Mirror podcast.
#history #maritime #maritimehistory #maritimeeducation #anchor #historyfacts #historygk

[@Thundercat735]

For a full audio podcast on the history of the marine propeller check out the Mariner's Mirror podcast? ...Okay I'm here. Where is it?

[@rude1802]

So did I.. 😂

[@henrymccoy2306]

It’s on Spotify.

[@deeptimansarkar2357]

Same

[@dennissorensen8765]

@@henrymccoy2306 oh ... that sucks. 😔

[@ВиктроКранов]

Algae in the water: Oh, this is my client!

[@Jogannez]

animation is wrong. these blades would push water in opposite directions

[@vallabhaacademic4249]

wow

[@kostar5]

it makes no sense , one of the Propeller should rotate the other side

[@chompipro5731]

The 3d Design is bad, but the blue print is correct

[@drewdoestrucks]

This technology is actually still used, just with counter rotating screws that eliminate the inefficiency inherent in this design from the cutouts in each blade. The design in this video would cause massive cavitation (and by the way the pitch is backwards in this video, those props would fight each other).
A modern design can be seen here as used by Yamaha on their lowers: ua-cam.com/video/chfDSJ2d_a4/v-deo.html

[@WreckChris]

I was indeed wondering about the cavitation between the cutouts.

[@justusbarnhart176]

One of the props should definitely be in the opposite angle