propellerblades

What a fabulous old picture. Thank you for sharing and making this picture available to all who are interested in things nautical.

It's a pleasure. I'm glad you're enjoying the photographs

Thanks for sharing these - they are great to see. I note a big difference in the geometry of the inboard and outboard props - is that because the shafts ran at different speeds?

Mauretania's trials of 1907 recorded shaft revolutions of between 123 per minute at 18.32 knots and 192 per minute at 26.17 knots with no indication that the speeds varied from shaft to shaft. However even at the trials stage Cunard and Swan Hunter & Wigham Richardson found that they were having vibration problems with Mauretania's 3 bladed propellers. These were later replaced with 4 bladed propellers. As far as I understand it all four propellers where changed and I suspect that this photograph was taken part way through the process. You can see that the two outboard propellers have 4 blades and the two inboard ones have three. If you look at the starboard inboard propeller you can see that it appears to have been nibbled! I would suggest that replacement with a 4 bladed type is imminent. However most of our reference material is concerned with the building of the ship at Wallsend so if anybody out there can suggest a different explanation I would be delighted to see it added.

I should mention that the response above came from our Keeper of Maritime History

I take it these are the "experimental Japanese wooden props"?