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Adam Leet
Member
Username: leet
Post Number: 308
Registered: 5-2001
| | Posted on Sunday, January 19, 2003 - 4:21 am: |       |
I know, Tom. I have a copy of that book, if you're referring to Mark Warren's publication. I also read the page you referenced, too. If you're referring to Mauretania being capable of achieving far higher speeds than 30 knots, then you are mistaken. I did not see anything in the book that would indicate a tremendous speed increase.
I apologize if that's not what you were intending to discuss.
Adam |
Mark Chirnside
Member
Username: mark
Post Number: 1343
Registered: 1-2001
| | Posted on Sunday, January 19, 2003 - 9:20 am: | |
I am a bit confused here too. Looking at the papers I have, they mostly focus on the earlier ship of 1907.
If you are looking for data about 1927-8 and any changes, I might have some. I know that propellers were modified around that time.
As for proof of thirty knots or more, Tom, Cunard's own archives appear to back this up. She could not do it regularly, but did make 29 and 32 knots several times on actual service.
Best regards,
Mark.
Mark Chirnside, Warwickshire, England
http://www.hospitalshipbritannic.com/rms_britannic.htm |
Scott Reigel
Member
Username: scott_reigel
Post Number: 44
Registered: 7-2002
| | Posted on Sunday, January 19, 2003 - 11:25 pm: | |
According to Tom Hughes in “The Blue Riband of the Atlantic”, Mauritania did surpass 30 knots on one occasion. Appendix three – “RMS Mauretania speed records” states that during a cruise returning from Havana she traveled the 112 miles between Carysfort Reef Lighthouse and Juniper Inlet Lighthouse at an average speed of 32 knots (July 20, 1933).
There needs to be a big asterisk next to this “record” however since the prevailing Gulf Stream obviously helped out quite a bit. This is probably a good illustration of why distance traveled is not necessarily a good indicator of a ships record speed through the water. I am much more impressed by Mauritania’s Atlantic records including her 27 consecutive trans-Atlantic runs at 25.5+ kts.
As for the “secret engines”, page “v” of the introduction (written by Mark Warren) does mention that in November 1928 she was taken out of service for seven weeks so that “secret adjustments” could be made to her turbines and new pumps and condensers installed which raised her to 90,000 SHP. This sounds similar to what NASA has done with the shuttle engines in that they have been proven safe and routinely run at 104% of their design capacity.
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Mark Chirnside
Member
Username: mark
Post Number: 1344
Registered: 1-2001
| | Posted on Monday, January 20, 2003 - 7:29 am: | |
Hi!
Hughes is backed up by Cunard's records, though they go into more specifics.
While we're on the topic, I am not sure how the modifications could have significantly improved her speed? I may be confused.
I know Aquitania saw some changes in early 1934, to increase her speed. Those are also interesting.
Best regards,
Mark.
Mark Chirnside, Warwickshire, England
http://www.hospitalshipbritannic.com/rms_britannic.htm |
Michael H. Standart
Moderator
Username: mstandart
Post Number: 5308
Registered: 12-2000
| | Posted on Monday, January 20, 2003 - 4:24 pm: | |
Mark, I wonder if those modifications may have had something to do with more then just the engines. I understand that the Lucy and the Mauratania had some severe vibration problems at high speed. On the Lusitania at least, they were serious enough that some extra re-inforcements had to be added to the structure and they had to modify the propellers.
I wonder what else had to be beefed up?
Cordially,
Michael H. Standart
Equal Opportunity Curmudgeon |
Mark Chirnside
Member
Username: mark
Post Number: 1345
Registered: 1-2001
| | Posted on Monday, January 20, 2003 - 6:18 pm: | |
Hi Mike!
I know what needed beefing up, though not what was beefed up. You do well to bring this point up: if the engines' output was to be increased significantly, other changes would surely be needed. I am not sure about the condensers and their effect, though Aquitania's were modified in 1934 to improve her performance and so they presumably do improve a vessel's speed. The problem in her case was that with modified condensers, the propellers became inefficient due to excess 'slip' and needed modifying too.
I find it interesting that all this was going on in 1928 with the Mauretania. The Bremen was a challenge, but although she put up a gallant fight Mauretania did not have age on her side. Fatigue was noted on plating around the propeller bossings in the mid-1920s, while the stern frame itself was fatigued and suffering from cracks by 1930. I wonder if there was anything done there to strengthen the hull, in the light of the 'fight' looming? That area of the stern -- a pretty modern feature in 1907 I guess -- was under constant pounding from the four massive screws. If, say the r.p.m.s went from 180 to 210, that would surely massively increase the vibrational stresses and endanger the structure?
This might be an interesting (aka boring for non-techies!) thread.
Best regards,
Mark.
Mark Chirnside, Warwickshire, England
http://www.hospitalshipbritannic.com/rms_britannic.htm |
Michael H. Standart
Moderator
Username: mstandart
Post Number: 5315
Registered: 12-2000
| | Posted on Tuesday, January 21, 2003 - 5:35 am: | |
Interesting indeed. The whole thing you just outlined seems a picture perfect example of the 7th variable of Murphey's Law in action. To wit; Every solution breeds new problems!
Eric Sauder's book on the Lusitania goes into some detail about what needed beefing up. On page 32, he points out that the vibration was so bad at high speed that second class was litarally unlivable. The area had to be gutted out and virtually rebuilt from scratch.
Propellor design is as much art as science too. A set of wheels good for a certain speed weren't really that efficient at any other, and at high speed, the cavitation would create a racket that would be...to put it politely...memorable. As far as I know, the problems were never really licked. The best anyone could do was put bandaids on it to keep it all within acceptable bounds.
It's still a problem with ships today too. When my last ship went out on trials after a 10 month refit, a high speed run was put into the deal. Not one single machine in my laundry was operating, but the noise from the cavitation was so bad my people had to wear hearing protection down there.
I can only imagine what it was like on the Lucy. They didn't have the advantage of nearly a century of research, development, testing, and evaluation that we enjoy today.
Cordially,
Michael H. Standart
Equal Opportunity Curmudgeon |
Mark Chirnside
Member
Username: mark
Post Number: 1346
Registered: 1-2001
| | Posted on Tuesday, January 21, 2003 - 6:50 pm: | |
Yes, it must have been worse. Still, I find it especially interesting that even today we cannot get that much right.
Overall, I suppose Mauretania and her sister did quite well to survive as they did. After all, no one had put that much power into a ship before. One might even have expected a good lot of structural failure.
Best,
Mark.
Mark Chirnside, Warwickshire, England
http://www.hospitalshipbritannic.com/rms_britannic.htm |
Michael H. Standart
Moderator
Username: mstandart
Post Number: 5326
Registered: 12-2000
| | Posted on Wednesday, January 22, 2003 - 8:37 am: | |
I think the only reason structural failures weren't more common was because the authorities kept a very close eye on things. Good thing too considering the troubles a lot of these hulls had.
The Limperator...uh...Imperator comes to mind. Can you imagine what it would have been like if nobody paid attention to the issues that ship had? Lawd ha' mercy!
Cordially,
Michael H. Standart
Equal Opportunity Curmudgeon |
Steven B. Anderson
Member
Username: samuelcunard
Post Number: 129
Registered: 8-2002
| | Posted on Thursday, January 23, 2003 - 4:15 am: | |
Mark wrote:
"I know Aquitania saw some changes in early 1934, to increase her speed. Those are also interesting".
To get off the subject a little, I have in my collection someplace details of the rebuild of Aquitania's turbines in Boston during 1942 in which her speed was also increased again.
I think we spoke of this prior.
Do you remember this thread and have the details on it, as I have misplaced my notes at the moment?
As for the Aquitania's Return Maiden Voyage
5 Days 11 Hours 58 Minutes / 3905 Nautical Miles New York to Liverpool / Average Speed 23.45 Knots (1914)
In 1936, when she was 22 years old she made a passage in 5 days 10 hours and 6 Minutes averaging 24.28 Knots.
Mauretania's average speed for the year of 1908 one year after she was place in service was 24.86 Knots.
What make these numbers impressive for the Aquitania is that she wasn't built for speed.
In 1939, when the Aquitania was 25 years old she steamed from Ambrose Light to Cherbourg in 5 Days 8 Hours and 44 Minutes at an average speed of 24.85 knots.
In 1949 on her last voyage her speed was 18.24 Knots as the log abstract is attached below
Steven B. Anderson
Samuel Cunard@aol.com |
Mark Chirnside
Member
Username: mark
Post Number: 1348
Registered: 1-2001
| | Posted on Thursday, January 23, 2003 - 7:45 am: | |
Hi Mike!
Yes, the good old Limperator. On the topic of her, she had something funny done to her boilers in 1935. (Useless trivia -- watertubes?)
Hi Steve,
Thanks for another informative post.
To get off the subject a little, I have in my collection someplace details of the rebuild of Aquitania's turbines in Boston during 1942 in which her speed was also increased again.
I think we spoke of this prior.
Do you remember this thread and have the details on it, as I have misplaced my notes at the moment?
I seem to remember that you spoke of some changes in 1940 in a thread on the Titanic Mailing List. A word search could bring that up, but turbines were mentioned.
Those voyages by Aquitania are very impressive. I should think that by 1939 she was faster than when she was new, as there had been so many changes made to her. It seems that she truly did get better with age.
I seem to remember seeing the extract, you sent it to me in a private e-mail after I sent you those scans on Aquitania's 1929 refit.
Out of interest, I have a list of Aquitania's average speeds for 1931 -- would you be interested in them as well? None of them were particularly fast, but they are regular, and of course that was the year when she got battered by storms and lost rivets, got girders cracked and so on.
Best regards,
Mark.
Mark Chirnside, Warwickshire, England
http://www.hospitalshipbritannic.com/rms_britannic.htm |
Michael H. Standart
Moderator
Username: mstandart
Post Number: 5337
Registered: 12-2000
| | Posted on Thursday, January 23, 2003 - 6:21 pm: | |
What funny thing Mark? Were the boilers retubed? Did it work? (Now there's a dicey question for you!)
Cordially,
Michael H. Standart
Equal Opportunity Curmudgeon |
Mark Chirnside
Member
Username: mark
Post Number: 1351
Registered: 1-2001
| | Posted on Thursday, January 23, 2003 - 6:28 pm: | |
Hi Mike,
I wish I knew! Colloidal Fuel trials were held onboard 1935-36; but as regards boilers I recall seeing somewhere about watertubes? I know next to nothing about boiler design.
Best regards,
Mark.
Mark Chirnside, Warwickshire, England
http://www.hospitalshipbritannic.com/rms_britannic.htm |
Michael H. Standart
Moderator
Username: mstandart
Post Number: 5339
Registered: 12-2000
| | Posted on Friday, January 24, 2003 - 6:00 am: | |
I'm not exactly a marine engineer myself. I wouldn't be surprised if some of them had to be replaced. The things are always in an environment of extremely high heat and pressure and that's not kind to metal.
Perhaps you can dig something up the next time you drop in on the PRO. Somebody had to do the survey work on the thing.
Cordially,
Michael H. Standart
Equal Opportunity Curmudgeon |
Mark Chirnside
Member
Username: mark
Post Number: 1354
Registered: 1-2001
| | Posted on Friday, January 24, 2003 - 8:42 pm: | |
Ummm... I'll add that to my 10 page 'to do' list. It comes to something when you are in double figures.
(Now what else about Mauretania and Aquitania's engines shall we talk about?!) 
Best regards,
Mark.
Mark Chirnside, Warwickshire, England
http://www.hospitalshipbritannic.com/rms_britannic.htm |
Brent Holt
Member
Username: brent_holt
Post Number: 65
Registered: 6-2002
| | Posted on Friday, January 31, 2003 - 11:23 pm: | |
"This sounds similar to what NASA has done with the shuttle engines in that they have been proven safe and routinely run at 104% of their design capacity. "
Actually, not to get off subject, but the main engines of the shuttle were designed to operate at 109% of capacity from early on. Recent re-designs have cleared the engies for 109% operation. The shuttle is a case of a powerplant coming in at below designed capacity.
Brent
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