Titanic's Central Propeller


Jim Currie

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It sounds like you're unfamiliar with Lusitania and Mauretania.

The 'real life' experiments of both ships with numerous different propeller configurations is well documented, including four bladed units and three bladed units, as well as a mixture of both on the same ship!

The experimentation of Harland & Wolff with different propeller configurations for Olympic, Titanic and Britannic is also well documented.
You are correct, Mark.

I was asked for my thoughts and based them on simple logic.
However, as a former Builder's Risk surveyor at John Brown's old Yard, Clydebank, and as a serving officer, I am familiar with experimental trials on ships and many other marine craft.

Now back to the subject.

If this change of central propeller was indeed experimental work then we are discussing an experiment on a new ship which had to have been contemplated before there had been enough time to evaluate the performance of her sister - a sister which had only been in service for 3 months before having to return to dock for repairs and had only completed 6 monthsof her live before having to go back to drydock once more. The WSL shareholders and The City must have been having deep thoughts about the future when Olympic arrived back at Belfast in early 1912. Hardly the time to experiment would you say?
 
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I cant help thinking this should of been sorted out before the 1908 order was place?
Think again. Only so much can be learned during the design stages. Anyone involved in producing a product, a system, or even a network, knows that you have to get it out into the "real world" to see how it actually performs under real world conditions. That's true today as it was back then.
 
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Think again. Only so much can be learned during the design stages. Anyone involved in producing a product, a system, or even a network, knows that you have to get it out into the "real world" to see how it actually performs under real world conditions. That's true today as it was back then.

Absolutely.
 
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To shift the subject slightly, it is on record that Titanic was expected to do a little better than Olympic in overall speed performance. By that I mean for a given number of revolutions, Titanic was expected to run a fraction of knot better, perhaps as much as 1/4 to 1/3 knot. Anyone want to guess as to what that would mean to a ship owner, even for such a small amount?
 

Jim Currie

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Think again. Only so much can be learned during the design stages. Anyone involved in producing a product, a system, or even a network, knows that you have to get it out into the "real world" to see how it actually performs under real world conditions. That's true today as it was back then.
Truer today than it was back in the 1950s and almost unheard of in shipbuilding.
Then, a change was made to a ship design as a result of adverse reports, change of use, and/or change in owner requirements or an unforeseen problem.
On the other hand, experimentation was done by individuals hence the plethora of industrial revolution inventions
However, in 1912, a 3 blade propeller was hardly an untried, new product being marketed by the producer. The problem was one of speed v. vibration.
There is no way that Harland & Wolff as builders changed the center propeller type without the consent of the customer. Nor was there any way that the builder could precisely know when the new build was going to be ready to fit propellers. Consequently, all arrangements for the casting of propellers were made well ahead of time.
 

Mike Spooner

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Truer today than it was back in the 1950s and almost unheard of in shipbuilding.
Then, a change was made to a ship design as a result of adverse reports, change of use, and/or change in owner requirements or an unforeseen problem.
On the other hand, experimentation was done by individuals hence the plethora of industrial revolution inventions
However, in 1912, a 3 blade propeller was hardly an untried, new product being marketed by the producer. The problem was one of speed v. vibration.
There is no way that Harland & Wolff as builders changed the center propeller type without the consent of the customer. Nor was there any way that the builder could precisely know when the new build was going to be ready to fit propellers. Consequently, all arrangements for the casting of propellers were made well ahead of time.
There is no way that Harland & Wolff as builders changed the center propeller type without the consent of the customer.
What does Bruce Ismay of WSL know about ship building? That belong to H&W. WSL is a service company shipping passengers and cargo A-B, you have to believe and trust H&W to do so. WSL is a commercial company they just want a reliable ship to run as profitable. If you want to experiment with new technology that belongs to Navy who got pots of Government money to throw at the new project.
I see H&W taking bit of a gamble and risk before doing there home work first with the centre propeller design. As would turnout there doesn't seem much different between the three or four centre bladed propeller.
 
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There is no way that Harland & Wolff as builders changed the center propeller type without the consent of the customer.
What does Bruce Ismay of WSL know about ship building? That belong to H&W. WSL is a service company shipping passengers and cargo A-B, you have to believe and trust H&W to do so. WSL is a commercial company they just want a reliable ship to run as profitable. If you want to experiment with new technology that belongs to Navy who got pots of Government money to throw at the new project.
I see H&W taking bit of a gamble and risk before doing there home work first with the centre propeller design. As would turnout there doesn't seem much different between the three or four centre bladed propeller.
"As would turnout there doesn't seem much different between the three or four centre bladed propeller."
Not sure it's relevant to the discussion but just a point of curiosity. Would you happen to know if one was more common during the time of Titanic? As in did most ships have 3 or 4 bladed props during those days? The pictures I have looked at seem to be 3 bladed but that doesn't prove much. The picture below shows some prop work. The reason I posted that pic is because besides being a cool pic (IMO) somebody had a really good camera for 1889. And it seems prop work was a common thing. Cheers.
T5-tu9DRPgaKdlH6oBUixq9EyvZkSXJIZ9oCv8muzXU.jpg
 
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Would you happen to know if one was more common during the time of Titanic? As in did most ships have 3 or 4 bladed props during those days?

In terms of ships Harland & Wolff built with combination machinery prior to 1914, Olympic was the odd one out in having a four-bladed centre propeller in 1911. This is covered in my article:

 
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Mike Spooner

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It would appear there is a new trend towards a four bladed propeller over the standard three bladed propeller in progress for passenger liners. Like any new in technology there is always a certainty amount unknow where the odd modifications are required for fine tuning. So H&W have covered them self by having both three and four propellers.
 
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In terms of ships Harland & Wolff built with combination machinery prior to 1914, Olympic was the odd one out in having a four-bladed centre propeller in 1911. This is covered in my article:

I just re-read the article. Thanks. Answered my question. It's very informative. Reading thru it another question kept popping up in my mind. Which is does anybody know the lead time for ordering a prop for these ships? The order for Olympic and Titanic went in at the same time. We know there were changes made to Titanic being completed later. And Olympic was on the water while Titanic was still being built. What I'm getting at is was there enough time to change the prop order for Titanic? Or would her 3 bladed prop need to be ordered at the time of the original order? Or could the industry make them rather quick? His spreadsheet lists the four bladed prop for both Olympic and Titanic. As does the 3 bladed prop specs. The specs are for both ships not one for Olympic and one for Titanic. I'm curious if after running Olympic after almost a year with the 4 blade the decision was made later to go back to the 3 blade which H&W seemed to prefer. Sorry there's so many question in this but its got me curious more than before. Cheers.
 
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What I'm getting at is was there enough time to change the prop order for Titanic?

Who said the order was changed?

There's certainly been a lot of confusion on this thread with various people claiming the order was 'changed'. There is no evidence this was the case.

We know from H&W's records that Olympic was fitted with a 4-bladed centre propeller in 1911 and Titanic was fitted with a 3-bladed centre propeller in 1912.

We also know from the notebook in Stephen Pigott's papers that a 4-bladed centre propeller and a 3-bladed centre propeller were part of the working design c. summer 1910. The only change between those designs and the final specification was that the pitch of these propellers was standardised.
 
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Mike Spooner

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Since there are no photo and signed document of three bladed centre propeller was ever fitted to Titanic, but looking at Mark research with Stephen Pigott article is pretty strong evidence that three bladed propellers were made for Olympic class ships. Yet Stephen was working for a arrival shipyard John Brown shipyard Ltd. So why are they involved? It would appear H&W have not kept pace with the new technology of steam turbines where John Brown has done so. There are seven shipyards using turbines, Parsons the most used where John Brown has taken out a licence to make Parsons turbines and have a join agreement to make the Curtis turbines known as the Brown/Curtis turbines. You also need the correct propeller design for the increase speed to. Charles Parsons is regarded as the king pin in propeller design suited for turbine speeds. As from 1908 John Brown will have a 52% stake in H&W. H&W have another problem as a arrival shipyard across the river to them Workman and Clark have already produced the first Ocean going steam turbine passenger liner Victorian maiden voyage March 1905. H&W need some catching up here with the new turbine technology. What a better opportunity to tie within John Brown shipyard who will make the turbines for Laurentic, Olympic & Titanic and to catch up with turbines. Four bladed propeller is some thing new for passenger liner ships to, apply caution here and what better to have a back up plan of a three bladed centre propeller as well!
 

Cam Houseman

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Since there are no photo and signed document of three bladed centre propeller was ever fitted to Titanic, but looking at Mark research with Stephen Pigott article is pretty strong evidence that three bladed propellers were made for Olympic class ships.
Britannic also had a four bladed prop, I saw it in a wreck picture, I think.
 
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Britannic also had a four bladed prop, I saw it in a wreck picture, I think.

Yes, Britannic only had a 4-bladed centre propeller; Titanic only had a 3-bladed centre propeller and Olympic had a mix at different times: a 4-bladed centre propeller in 1911, changed to 3-bladed in 1913 and then changed back to a 4-bladed centre propeller (by 1919 at the latest).
 
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Britannic also had a four bladed prop, I saw it in a wreck picture, I think.
You thunk right. There are pics of her center prop on the wreck. But there's really no doubt at all about Britannic's center prop. Some of the younger crowd like to use the phrase if it's not on video it didn't happen. Well there is video. You can skip to the 3:30 mark if you want. Cheers.
 
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Mike Spooner

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Britannic is a Olympic class ship therefore she to could of had a three bladed centre propeller to. But one has to take it they found out on Olympic between three and the four bladed propeller, four bladed was the better choice. The only thing delay in time for the Olympic change over was the War years.
When the Olympic was changed over in 1913 to three bladed it make me think there were not quite convince of the right choice yet.
 
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Britannic is a Olympic class ship therefore she to could of had a three bladed centre propeller to.

In theory, this might have been the case had Olympic's performance with the 3-bladed propeller been superior. However, there's no doubt Britannic was completed with a 4-bladed centre propeller because this is documented in H&W's records; in film and photo; and by the wreck.

When the Olympic was changed over in 1913 to three bladed it make me think there were not quite convince of the right choice yet.

They did not have the data because Titanic sank.
 

Mike Spooner

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I don't dispute that Britannic was launch with a four bladed propeller. If wasn't for the war years more information on performance between the two ships could have taken place. In fact I believe the Britannic never made a Atlantic crossing which she was design for.
As if a three bladed propeller was made for Olympic at the same time as the four bladed, which then the three bladed propeller comes a expensive spare part hanging around. So why not try it on the Titanic!
 
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As if a three bladed propeller was made for Olympic at the same time as the four bladed, which then the three bladed propeller comes a expensive spare part hanging around.

It wasn't.

A 4-bladed centre propeller was used on Olympic in 1911; a 3-bladed centre propeller was used on Titanic in 1912; and a 3-bladed centre propeller (similar to the Titanic version but not identical) was used on Olympic in 1913.
 

Mike Spooner

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Now that is a surprise that the Olympic and Titanic centre propeller are not identical! After all Titanic never completed her first crossing. Or do think they again enough information before the sinking to make changes?
 

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