Titanic's Central Propeller


Sep 13, 2003
24
0
131
Hi Mark
Just read your article on the Titanic's central propeller , was very interesting. When I was at Belfast, PRONI were extremely helpful and patient supplying stuff but a few things are still held by Harland & Wolff themselves and you needed there permission to examine them. Was curious, did they give any idea why these particular items are held by Harland & Wolff. Not that I have any objection, it is their material after all!!!

Regards

Richard

[Moderator's Note: This post, originally posted in a separate topic, has been moved to the one which is discussing articles submitted to ET. JDT]
 
Jan 5, 2001
2,304
140
338
I appreciate the very kind comments, Richard and Michael.

I am not sure I can answer your query, Richard. I assume it is merely company policy.

Best wishes,

Mark.
 
Apr 26, 2020
4
2
3
Dear Mr. Woolcock and Community,

Intriguing topic. The notebook seems to give a valuable clue, although no dates of original layouts and changes are entered. Also, the writing is not 100% discernible at certain places. Perhaps a separate enlargement of the bottom half of the left page would be helpful.
At the moment, i read the data like this:

Project no. 400 (Olympic)
Reciprocating
Propeller diameter: 23'-6"
Blade pitch: 33'-6" (changed into 34'-6")
Blade area: 160 sq. ft.
Blades: 3
Turbine
Propeller diameter: 16'-6"
Blade pitch: 14'-6"
Blade area: 120 sq. ft.
Blades: 4

Project 401 (Titanic)
Reciprocating
Propeller diameter: 23'-6"
Blade pitch: 34'-6"(changed into 35')
Blade area: 160 sq. ft.
Blades: 3
Turbine
Propeller diameter: 17'-0" or 17'-6" (hard to make out in the writing)
Blade pitch: 14'-6"
Blade area: 120 sq. ft.
Blades: 3

The 3-bladed prop on 401's turbine shaft is one foot larger in diameter, yet each blade still has a surface area of 120 square feet, meaning that the blades have a slightly more slender shape. 360 square feet (3 blades) thrashing through the water at a certain rpm require less horsepower than driving 480 square feet ( 4 blades) through the water, with the same pitch at the same rpm. So, the 3 bladed prop may have been an experiment to allow the turbine to run at a higher rpm, possibly to improve its efficiency or to lighten its load. Increasing the blade pitch of the two wing props would mean a higher load on the reciprocating engines and would reduce their rpm, saving steam (unless the boilers would be made to generate more psi to compensate). Less steam through the reciprocating engine would mean less LP steam through the turbine, making it necessary to lighten its load in order not to lose too much rpm.

Kind regards, greetings from the Netherlands
 
  • Like
Reactions: 1 user

Jeff H

Member
Dec 16, 2020
2
0
1
now this is an interesting bit of history.
even more interesting is that there is one photo that I've found of one of the sisters, showing a 4 bladed central prop, where the hull seams do not line up with either the Olympic or Brittanic.
that image is an old stock image historic-1912-image-of-rms-titanic-rudder-and-propellors-with-group-of-ship-workers-in-the-huge-dry-dock-construction-site-adding-scale-to-the-huge-ocean-liner-harland-and-wolff-shipyard-belfast-uk-PK06RX.jpg (1300×1089) (alamy.com)

the specific seam I am looking at is on the plate running from the trailing edge of the outrunner to the leading edge of the prop cutout, both Olympic and Brittanic have a vertical seam in that plate
 

Thomas Krom

Member
Nov 22, 2017
129
225
88
now this is an interesting bit of history.
even more interesting is that there is one photo that I've found of one of the sisters, showing a 4 bladed central prop, where the hull seams do not line up with either the Olympic or Brittanic.
that image is an old stock image historic-1912-image-of-rms-titanic-rudder-and-propellors-with-group-of-ship-workers-in-the-huge-dry-dock-construction-site-adding-scale-to-the-huge-ocean-liner-harland-and-wolff-shipyard-belfast-uk-PK06RX.jpg (1300×1089) (alamy.com)

the specific seam I am looking at is on the plate running from the trailing edge of the outrunner to the leading edge of the prop cutout, both Olympic and Brittanic have a vertical seam in that plate

1608134920716.png

Here is the original photograph taken by Robert Welch, Harland and Wolff their personal photographer. The catalogue number in the right corner at the bottom (1512) is part of a set of Olympic in the Thompson Graving dock in April 1911. This means that could have impossibly come from the Titanic, which was launched a bit more than a month later. Robert Welch took a total of 5 pictures up close of the Olympic in drydock numbered 1511 to 1515. Here are the other pictures if you are intrested to see them.
1608134872687.png

1511. Triple propeller arrangement and rudder, portside view from dock floor, with three figures.

1608134974523.png

1513 Triple propeller arrangement, rudder and underside of counter from port side of graving dock.
1608135013299.png

1514 Port stern profile of counter, rudder and centre propeller from side of graving dock.
1608135076745.png

1515 Port bow profile from side of graving dock with pump house and chimney in background.
 
  • Like
Reactions: 4 users

Tim Gerard

Member
Feb 26, 2019
162
82
73
Today, the propellers are buried in the mud on the ocean floor, right? How easy or possible would it be for a future expedition to use some kind of fancy sonar or something to "see" the propeller through the mud and determine for sure if it's 3 or 4 blades? I remember seeing a documentary about an expedition in the 90s that looked for the iceberg damage, and they used sonar or something to "look" at the part of the starboard bow section that's buried in the ocean floor and confirmed the damage to be a series of slits. Assuming they can get funding (which I imagine would be the biggest hurdle), I'm just curious how feasible it would be.
 
  • Like
Reactions: 1 user

Kate Powell

Member
May 27, 2020
57
45
38
UK
View attachment 74730
Here is the original photograph taken by Robert Welch, Harland and Wolff their personal photographer. The catalogue number in the right corner at the bottom (1512) is part of a set of Olympic in the Thompson Graving dock in April 1911. This means that could have impossibly come from the Titanic, which was launched a bit more than a month later. Robert Welch took a total of 5 pictures up close of the Olympic in drydock numbered 1511 to 1515. Here are the other pictures if you are intrested to see them.
View attachment 74729
1511. Triple propeller arrangement and rudder, portside view from dock floor, with three figures.

View attachment 74731
1513 Triple propeller arrangement, rudder and underside of counter from port side of graving dock.
View attachment 74732
1514 Port stern profile of counter, rudder and centre propeller from side of graving dock.
View attachment 74733
1515 Port bow profile from side of graving dock with pump house and chimney in background.
Thank you for sharing the images, Thomas.
 
  • Like
Reactions: 1 user

Similar threads

Similar threads