Fourth Funnel a vent


Mar 3, 1998
2,745
4
0
The reduction in height for the funnels is interesting. The height of the funnels was not, as is so often claimed, determined by aesthetics, the need to keep smoke and soot away from the passengers, or even to reduce the effect of the snap roll (although all of these would have been of consequential effect). Being of the natural-draught type, Olympic's boilers required a tall funnel in order to maintain a substantial air pressure inside the combustion chamber. This, in turn, affected the amount of coal needed per sq. ft. of grate area to produce the required steam pressure. Reducing the funnel height for a set of natural-draught boilers would normally reduce the chimney draught height, which would in turn increase the amount of coal needed per sq. ft. of grate and lower the overall efficiency of the boilers. Taken in this light, the 9-ft. reduction in the height of Olympic's funnels is intriguing...what drove that reduction? If it truly was taken in order to improve the stability characteristics of the vessel, was White Star willing to pay the cost of the extra coal needed to maintain boiler pressure? Or, did a more efficient type of boiler become available between concept and execution that did not require as high a chimney draught as originally expected? Answer these questions and you will have your answer for the curious reduction in funnel height for Olympic.

Parks
 
Dec 4, 2000
3,241
488
213
In assessing the four structures it is wise to keep in mind that good naval architecture involves gaining the most use out of minimal construction. And, that no matter what you build in a ship, it is a compromise.

What are commonly called "funnels" on Titanic are case in point. They did a lot of things in addition to serving as uptakes for the furnaces. They served as whistle mountings, steam pipe supports and even part of the water distribution system. Their weight was part of the ship's stability and helped with roll control. This multi-fuction use of the four structures is indicative of good naval architecture.

In 1912 more so than today, naval architects strove to make their creations "eye sweet." The final ship was to be pleasant to gaze upon.

The "funnel" part of the structure consisted of the uptakes from the furnaces and what ashore might be called a "chimney" carrying hot gasses and ash well above deck. As Parks points out, in a natural-draught ship height of the "chimney" greatly influences the efficiency of the boiler furnaces.

Given that the riggers who could keep a windjammer's upper topmast standing in a hurricane were still alive and actively working at their trade, a relatively lightweight metal stovepipe "chimney" could have been erected about as tall as any boiler furnace could have wanted. The riggers would simply have put up the required shrouds and stays to keep the pipe "in column" under any condition of weather. They not only had the technology, but also the hands-on experience to accomplish a tall, lightweight stovepipe.

Gawd! Was that U-ugly. You can see for yourself by checking out freighters on the Great Lakes which at the time had just such stovepipe stacks. Stick-in-the-eye ugly!

An eye-sweet design demands a larger diameter structure of lesser stature. And, that aesthetic requirement is a happy marriage with the need to place weight aloft to improve the comfort factor.

So, H&W wrapped the "chimney" with a large, cylindrical casing normally referred to as a "funnel" even though this casing served primarily the weight balance function.

At this point in the design cycle there would have been a tug-of-war between providing draught to the furnaces and comfort to the passengers. Complicating matters would have been providing that "eye sweet" finished product. More than likely, the height of the complete funnel/casing structure underwent a number of height iterations, probably including a shorter version that we have yet to see.

In this give-and-take argument the three factors would have been given a "pecking order." Most likely, it would have been: 1.) furnace efficiency; 2.) weight balance; and 3.) aesthetics.

In the end, I doubt that erasures on the H&W plans indicate a major "change" in the design of the Olympic class funnels. Rather, I suspect they are evidence of the ongoing design process which produced the "compromise" height actually built. In the end, what was built is what was intended, and is by definition the "correct" height for the funnels.

--David G. Brown
 
S

Scott R. Andrews

Guest
Hi Parks,

That's precisely the sort of "practical" consideration I had in mind regarding the change in height of these funnels. In order of importance, draft was the primary consideration where the height was concerned, with the affect on righting arm coming in as a close second. Regarding the draft, a second and by no means less-important factor in designing the funnels was the cross-sectional area of the actual flue, or "inner funnel." In the case of the Titanic, while the height of the each funnel above the firebars was approximately the same, the cross-sectional area of each of the inner funnels was different, being sized according the square feet of furnace grate surface being served. Here, aesthetic considerations were served by making the cross-sectional dimensions of the outer funnel the same for all funnels, so that they appeared identical in form. Returning to the question of the adjustment in height, while it's not possible to determine what the specific reason was for doing this, assuming for the sake of discussion that stability was the consideration, then they may have been able to change the dimensions of the inner funnel to compensate for the reduction in height, thereby avoiding any penalty to the draft within the uptakes and funnel.

Of course, your comments regarding funnel height in relation to draft bring to mind HAPAG's Imperator. Now, here is a case where the funnels were reduced in height as part of a series of drastic changes to improve stability, but Imperator's funnels were altered after the ship had begun service; with the Olympic, the change was made on the drafting board while there was ample time to consider the effects of these changes on the rest of the system. In the case of the Imperator, nothing more than the reduction in funnel height was carried out -- there was no re-sizing of the inner funnels or uptakes, adjustments which would likely have been required to maintain the draft within the system at the level required for best fuel consumption. Throughout her life, first as the Imperator and then as Cunard's Berengaria, this ship was plagued by high fuel consumption. I had always assumed that this was due to problems experienced with the early watertube boiler designs coupled with the lack of efficiency in direct-drive turbines, but this discussion has me wondering if poor draft wasn't at least partly to blame for her troubles.

Regards,
Scott Andrews
 
Mar 3, 1998
2,745
4
0
Scott,

The equations used in 1911 to calculate boiler efficiency include both stokehold pressure and chimney draught (both measured in inches of water) as variables. With forced-draught systems, the chimney draught does not have to be as high in order to result in the same furnace combustion rate, which explains why funnels became shorter over the years. I wonder if the Germans got caught up in an aesthetic trend and reduced the funnel height before they could develop an efficient forced-draught system, resulting in the inefficiencies you noticed with the Imperator.

You make a good point about the aesthetic considerations concerning the outer funnel casing diameter. The designers had to juggle boiler efficiencies, topside weight considerations and pure aesthetics when incorporating the funnels into the whole-ship design. A follow-on thought to this is that if the funnel design doesn't help with boiler efficiencies, then additional bunker space is required below to hold the extra coal needed. Designing a ship is no easy matter because a compromise in one area often results in a forced and usually unintended compromise somewhere else. The fact that the H&W engineers later changed Olympic's funnel design is interesting to me because I would like to know what drove the change. Did some engineer lose his argument and subsequently left frustrated with the result? This happens quite often in ship design, even to the present day...I have been forced to make changes to my area of the DDG-1000 design that were driven by changes made in other areas.

Parks
 
S

Scott R. Andrews

Guest
Hi Parks,

You are no doubt aware of the many photos of the Imperator taken during the various stages of her maiden arrival at NY, which show the ship listing to one side or the other, and with her list changing in response to even the slightest shift in the breeze or in response to any alteration in the ship's heading. Even when lying fully laden at the pier, photographs taken from the pier head nearly always show the stem leaning away from the vertical to one side or the other. (It was with good reason the Sandy Hook pilots referred to her as the "Limperator"!)

The funnel height change on the Imperator was not at all for aesthetic reasons. Rather, it was part of a drastic effort to reduce topside weight, a program which was carried out during the ship's first overhaul at the conclusion of her inaugural season. Apparently, replacing all of the vitreous china bath tubs in 1st Class with enameled iron ones, replacing God-only-knows how many tons of marble dado and backsplash in the baths throughout 1st Class with ordinary partition joinery, replacing much of the heavy public room furniture with wicker, and then even adding several thousand tons of permanent cement ballast to portions of the double bottom weren't enough, so they resorted to removing steel from the highest structures on the ship. Even after all of this, the result was a ship that was tender at best.

Regards,
Scott Andrews
 
Mar 3, 1998
2,745
4
0
Scott,

Actually, I don't know that much about the Imperator...she hasn't really appeared on my radar screen. The only German liner that I know anything about is the Vaterland, and the only reason why I know about her is because my uncle's father worked in the Newport News shipyard and helped to convert her into the Leviathan. My uncle grew up in a house almost completely furnished in fittings and furniture from the Vaterland...his bedroom wall was made from 60 panes of etched glass from the ship's library (many years later, I would be approached by the man who eventually bought the house in Hampton to authenticate one of the glass panels...small world). His father's work must have impressed him, because my uncle would grow up to be the Second Engineer aboard the SS United States and even later own his own marine salvage company. But, I digress...

Parks
 
Dec 2, 2000
58,590
381
283
Easley South Carolina
>>Actually, I don't know that much about the Imperator...she hasn't really appeared on my radar screen.<<

Check it out sometime when you have a moment. I first heard about this ship in Maxtone-Graham's "The Only Way To Cross" and she was absolutely notorious for stability problems. The people in New York who worked with ships sarcastically dubbed her the "Limperator."

Reducing the hight of the stacks was but one "Corrective" measure in a long string of corrective measures that never really fixed the problem, up to eventually adding 6000 tonnes of concrete in the bottom as permanent ballast.

At best, they put bandaides on it, none of which ever really dealt with the other causes of the problem. You can look to the appointments in 1st Class as well, which included impressive amounts of granite, marble, wrought iron and heavy woods. This wasn't helpful.
 

Dave Gittins

Member
Apr 11, 2001
4,981
219
193
Does anybody have an authoritative source for the claim that the Olympic ships were originally to have three funnels?

I have a drawing published in US papers on 15 March 1908. It shows a rather inelegant ship with three funnels and three masts. She looks clumsy and untidy.

By 12 December 1909, the same drawing has been altered to show a four funnel two-master, vaguely resembling Olympic.

Are these early ideas from H & W, or a newspaper fantasy?
 
Feb 14, 2011
2,447
3
68
It's interesting how some liners underwent funnel makeovers during various upgrades.....
The Ile de France was one of my favorites ships- Correct me if Im wrong, but I do believe her original 3rd funnel was a dummy- And after her extensive upgrade, her 3 funnels were replaced bu 2 larger- yet shorther funnels- She certainly looked better after the funnel makeover.....

As for the shortening of the Europa's funnels (or was it the Bremen?)- It added to her appearance, but i never could understand what impact, if any, it would have on the dispersal of funnel exhaust....
Funnel height didnt always succeed in preventing the deck from becoming lost in a cloud of soot- I have seen many a photo of Lusitania where the smoke from her funnels seemed to be drawn down towards the deck-I suspect the angle of the funnel, as opposed to height would have more affect on what direction the smoke would take...

Of course when discussing funnels of modern cruise ships- they look downright bizzare....


regards


tarn Stephanos
118844.jpg
 
May 12, 2002
211
0
146
Hi Dave,

I'm sure I've seen a photo of a builder's model of Olympic with three funnels. I can see it in my mind's eye, but I'm darned if I can remember which book it's in. As I've just recently unpacked my collection, I'll have a browse through and see if I can find it.

Cheers

Paul
 
Mar 3, 1998
2,745
4
0
quote:

Check it out sometime when you have a moment.
Michael,

I'd like to, but I don't think that's going to happen. It's all a matter of priorities. There just isn't enough time in the day to do everything that I should be doing. All the time that I have for old steamship stuff is taken up by the Olympics. I've already given up most of my other hobbies (classic car restoration, WW2 re-enacting) to devote more time to Titanic. If I spend the time to learn about every liner ever built, then I would have to take away from my paying job, family, etc., and that's just not going to happen. In my opinion, there is more to life than ocean liners of the past, so there is only so much of the topic that I am willing to tackle. Instead, I depend on people like the experts in this thread who are more devoted to and knowledgeable about the entire history of passenger steamship service for the perspective I need to understand my own research. If I have a tidbit of information based on my experience and/or research that is relevant to your ongoing discussions, then I will contribute; otherwise, I defer to the experts.

Parks​
 

Lucy Burkhill

Member
Mar 31, 2006
166
1
88
>>I'm sure I've seen a builder's model of Olympic with three funnels<<

Paul, I can't speak for Olympic, but you may be interested to know that the earliest design for Lusitania (from 1902), shows her with only three funnels, and, incidently, three screws. In the M Warren reprint of the 1907 "Engineering" (p4 if anyone has a copy), there is a photo of the prototype Lusitania which has only three funnels. In his introduction Mr Warren mentions that initially, proposals submitted by the major British shipbuilders for the new superliners showed three funnels, however, Cunard eventually decided on four because the German express liners were all four-stackers, and so the prestigious British ships could have no less! Also, the book states that before WW1, passengers equated the number of funnels with the speed and safety of the ship, and therefore booked passage in great numbers on the four-stackers. This would most likely have been another reason for White Star to give the Olympic class their fourth funnel.

Lucy
 
Feb 14, 2011
2,447
3
68
Speaking of funnels- does anyone know if all five funnels on Brunel's great 19th century liner 'Great Eastern' were utilized, or were any of her funnels just for ventilation?

What an unlucky ship- She once suffered a boliler explosion, and a funnel shattered like a grenade....
One of her funnels is still around- after she was scrapped- a funnel was used as some sort of underground pipe...

In the classic book 'Damned By Destiny', there were plans for a 5 funneled German liner (that was never built) in the 1890s- Imagine what influence that would have had on other liners of that time, had that 5 funneled liner been built...


regards


Tarn Stephanos
 
B

Brian R Peterson

Guest
Hi Tarn,

The Great Eastern had five boiler rooms, one funnel and uptake for each so yes, all five were functional.

However, when she was commissioned as a cable layer, the forth funnel as well as the boilers it serviced were removed and the space made into a cable locker.

Best Regards,

Brian
 
Dec 2, 2000
58,590
381
283
Easley South Carolina
>>Does anybody have an authoritative source for the claim that the Olympic ships were originally to have three funnels? <<

I think I saw something in the endpieces of Birth of the Titanic, but I can't vouchsafe it's authenticity. The idea may have been kicked around in the early stages but this is typical of any ships design process, even today. Some quite fanciful "Artist's conceptions" show up in the media which seldom if ever bear any really close resemblance to what actually goes into the water. The idea of a three funneled ship may have been kicked around for the Olympics but if it was, it clearly didn't last long.

Parks, you may find http://www.greatoceanliners.net/index2.html to be of some interest. Personally, I'm wondering if the eighty lifeboats worked in to the design post Titanic served to aggravate the problems of an already tender ship. They couldn't have helped!
 
Dec 29, 2006
729
6
88
Witney
The explosion aboard The Great Eastern in September 1859 was not a boiler explosion. It was caused by a build-up of pressure in a feedwater heating system, which caused one of the funnels to blow up. This unusual incident was fully reported in The Times.
 
Feb 14, 2011
2,447
3
68
Thank you for the correction Stanley-
This makes me wonder about 'funnel mishaps'- Have other funnels on different ships exploded, unexpectly fallen over or caught fire due to accumulation of soot? With the threat of chimney fires in ones home being real, im sure funnel fires on some of the older liners were commonplace....



regards


tarn Stephanos
 
B

Brian R Peterson

Guest
Hi Tarn,

An interesting note about the feedwater pump explosion, aside from causing the death of I.K. Brunel when he learned of it, it also caused funnel No.1 to reportedly take off like a rocket.

Removed from the ship during repairs, the base of the damaged funnel was converted to act as a water strainer at a pumping station at Sutton Poyntz, near Weymouth, where until recently it formed an integral part of the system.

Donated by Wessex Water to the SS Great Britain Trust, the section is just over seven feet wide and over five feet tall and is the only remaining iron part still in existence of Brunel's third and final ship.

You can clearly see the base portion of one of the Great Eastern's funnels from this, the last photograph taken of I.K. Brunel just days before his death on September 15, 1859.

118864.jpg


Best Regards,

Brian
 
Dec 29, 2006
729
6
88
Witney
Hello Tarn,
I was trying to amplify your comments, rather than "correct" them - the effects of the explosion would certainly have been similar to those of a boiler failure. The sudden eruption of the funnel caused a major blow-back and filled the forward boiler room with steam and hot gases. William Briscoe, "The junior engineer of the paddle engine department", threw himself down and covered himself with his coat to escape the steam, but the stokers and firemen ignored his orders to stay put and climbed upwards into the hottest steam, as a result of which they were literally boiled alive. William Briscoe, who escaped with scalded hands, had to shelter under his coat for no less than five minutes until the steam had dissipated - this must have been a terrifying experience!
 
May 12, 2002
211
0
146
Hi again Dave,

So much for my mind's eye! I think I've found the photo I was remembering of the builder's model. It shows the cowl vents (which I remembered after I'd posted above), but it certainly has four funnels. Ah well...

Cheers

Paul
 

Similar threads