Dave Gittins
Member
Titanic is said to have done over 23 knots between Belfast and Southampton, I can't give a source offhand. Wind and current can do wonders. I've known my own little yacht to do 8 knots over the ground and 5 through the water.
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Aaron_2016
Guest
The newspapers between 1911 - 1919 reported her speed. Although it is unknown if some of the reports were just propaganda to boost her reputation. One newspaper stated that she made 27 knots during the war. Other papers reported her speed as 23 knots. Here is a more detailed account from 1914 which mentions her speed.
Olympic speeds across at 25 knots
New York Tribune - August 6th 1914
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Olympic speeds across at 25 knots
New York Tribune - August 6th 1914
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Mark Chirnside
Member
It was Edward Wilding who stated Titanic had attained 23 1/4 knots at some stage on the run between Belfast and Southampton.
Olympic was never driven at full speed for the duration of an entire crossing.
What we do know is that the White Star Line's own records up to 1915 showed that her best average speed for a day's run was 24.2 knots. No doubt that was on an eastbound run and aided by an obliging current!
It is important to distinguish between a ship's progress through the water and what she achieves over the ground. (It may be, for example, that in the scenario above Olympic ran at 23.7 knots and was aided by a 0.5 knot current.)
We need to bear in mind Olympic underwent numerous changes to her propeller configuration throughout her career. If we look simply at the pre-war years, she had her original 1911 configuration, then the wing propeller pitches changed in November 1911, then the wing propeller pitches and diameter changed in the 1912-13 refit and the centre propeller changed to a three-bladed configuration. Titanic's wing and centre propellers were different to Olympic's original 1911 or November 1911 configurations and H&W anticipated she would achieve up to a 1/4 of a knot more in speed in comparison to Olympic.
Over twenty years, the developments in propeller design yielded some remarkable results. In 1936, Cunard's Aquitania was fitted with new propellers which reduced her slip by a substantial proportion (it may have been half, IIRC) and this gave her owners the option of increasing her speed by 2.5 knots or maintaining her speed and reaping the benefits of reduced fuel consumption. If Olympic had been similarly upgraded, her maximum speed could have increased significantly.
Taking a particular ship with a known hull form and propulsion system, her maximum speed is also dependent on many other factors, like as her state of loading, the weather conditions and such like. There's no precise answer.
Best wishes
Mark.
Olympic was never driven at full speed for the duration of an entire crossing.
What we do know is that the White Star Line's own records up to 1915 showed that her best average speed for a day's run was 24.2 knots. No doubt that was on an eastbound run and aided by an obliging current!
It is important to distinguish between a ship's progress through the water and what she achieves over the ground. (It may be, for example, that in the scenario above Olympic ran at 23.7 knots and was aided by a 0.5 knot current.)
We need to bear in mind Olympic underwent numerous changes to her propeller configuration throughout her career. If we look simply at the pre-war years, she had her original 1911 configuration, then the wing propeller pitches changed in November 1911, then the wing propeller pitches and diameter changed in the 1912-13 refit and the centre propeller changed to a three-bladed configuration. Titanic's wing and centre propellers were different to Olympic's original 1911 or November 1911 configurations and H&W anticipated she would achieve up to a 1/4 of a knot more in speed in comparison to Olympic.
Over twenty years, the developments in propeller design yielded some remarkable results. In 1936, Cunard's Aquitania was fitted with new propellers which reduced her slip by a substantial proportion (it may have been half, IIRC) and this gave her owners the option of increasing her speed by 2.5 knots or maintaining her speed and reaping the benefits of reduced fuel consumption. If Olympic had been similarly upgraded, her maximum speed could have increased significantly.
Taking a particular ship with a known hull form and propulsion system, her maximum speed is also dependent on many other factors, like as her state of loading, the weather conditions and such like. There's no precise answer.
Best wishes
Mark.
Michael H. Standart
Member
Add marine growth fouling the hull in to sweeten the pot, wear and tear on the engines between overhauls....there's a lot of stuff to consider.
Mike Spooner
Member
Mark,
Question. She had her original 1911 configuration, then the wing propeller pitches changed in November 1911? Does that mean the ship was return to Thompson dry dock or was it possible to make changes whist in the water?
Mike.
Question. She had her original 1911 configuration, then the wing propeller pitches changed in November 1911? Does that mean the ship was return to Thompson dry dock or was it possible to make changes whist in the water?
Mike.
Mark Chirnside
Member
Mike
She was in dry dock anyway for repairs after the Hawke collision.
Best wishes
Mark.
She was in dry dock anyway for repairs after the Hawke collision.
Best wishes
Mark.
Mike Spooner
Member
Thanks Mark
Mike.
Mike.
Mike Spooner
Member
Hi Mark,
If the propeller blades pitch was change on the Olympic after only four return crossing. Isn't a rather short time for blade changes? I
I would of thought apply the propeller change pitch on the Titanic first and then do the two comparison. Or have I missed some thing here?
Mike.
If the propeller blades pitch was change on the Olympic after only four return crossing. Isn't a rather short time for blade changes? I
I would of thought apply the propeller change pitch on the Titanic first and then do the two comparison. Or have I missed some thing here?
Mike.
Aaron_2016
Guest
The Olympic was laid up in dry dock many times in 1911 - 1912
In November 1911 she collided with HMS Hawke and repairs were made with alterations to her propeller shafts. In February 1912 she lost a propeller blade and had to return to dry dock again. She then briefly ran aground on her departure from Belfast and had to return to dry dock yet again for inspection. She then lost another blade in August 1912 and had to return to dry dock, and then she another blade just a few weeks later in September 1912 and had to return to dry dock again. I think the owners decided that her propeller blades were not sufficient enough and they were replaced entirely with something better and she returned to dry dock again. After 1912 there were no more reports of the Olympic losing a propeller blade.
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In November 1911 she collided with HMS Hawke and repairs were made with alterations to her propeller shafts. In February 1912 she lost a propeller blade and had to return to dry dock again. She then briefly ran aground on her departure from Belfast and had to return to dry dock yet again for inspection. She then lost another blade in August 1912 and had to return to dry dock, and then she another blade just a few weeks later in September 1912 and had to return to dry dock again. I think the owners decided that her propeller blades were not sufficient enough and they were replaced entirely with something better and she returned to dry dock again. After 1912 there were no more reports of the Olympic losing a propeller blade.
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David G. Brown
RIP
Both metallurgy and propeller science were undergoing rapid changes and improvements during the early 20th century. The Wright Brothers study of propeller dynamics was key to heavier-than-air flight in 1903. But, it was advances in the metal alloys of propellers that probably most affected ships. New alloys allowed thinner blade sections, better aspect ratios, etc. Periods of rapid development are always fraught with mistakes, errors, and failures.
More modern examples include belt slippage in early steel belted auto tires; window "blow outs" causing fatal crashes of the first Comet jetliners; the Tacoma Narrows "galloping girty" bridge collapse; and train wrecks caused by inadequate brakes on railroad cars.
Olympic's troubles early on were the price paid for better speed and overall performance later in the ship's life. And, that suggests Titanic's screws were part of the evolutionary process -- probably better than Olympic's first three, but not as good as what would have been on the ship three or four years later.
To show how progress can outrun knowledge consider the term "screws" for propellers. It comes from the earliest efforts by John Ericsson and others. In the 1830s it was still widely thought that these fan-like devices "screwed" their way through the water and thus caused forward motion. The Wrights confirmed that propellers actually pull an airplane through the air by creating lift on their spinning blades. Yet, the old concept of screwing through the air or water remains stuck firmly in our language. Titanic was billed as a "triple-screwed" ship and props are still called "screws" today. Hmm... Currently, scientists and engineers are trying to figure out how to get rid of all those unwanted buckets of prop wash.
-- David G. Brown
More modern examples include belt slippage in early steel belted auto tires; window "blow outs" causing fatal crashes of the first Comet jetliners; the Tacoma Narrows "galloping girty" bridge collapse; and train wrecks caused by inadequate brakes on railroad cars.
Olympic's troubles early on were the price paid for better speed and overall performance later in the ship's life. And, that suggests Titanic's screws were part of the evolutionary process -- probably better than Olympic's first three, but not as good as what would have been on the ship three or four years later.
To show how progress can outrun knowledge consider the term "screws" for propellers. It comes from the earliest efforts by John Ericsson and others. In the 1830s it was still widely thought that these fan-like devices "screwed" their way through the water and thus caused forward motion. The Wrights confirmed that propellers actually pull an airplane through the air by creating lift on their spinning blades. Yet, the old concept of screwing through the air or water remains stuck firmly in our language. Titanic was billed as a "triple-screwed" ship and props are still called "screws" today. Hmm... Currently, scientists and engineers are trying to figure out how to get rid of all those unwanted buckets of prop wash.
-- David G. Brown
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