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Fourth Funnel a vent

Discussion in 'Funnels & Whistles' started by Roy Howes, Feb 18, 2007.

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  1. Roy Howes

    Roy Howes Member

    Hi all,
    I know the aftmost funnel was ftted for aesthetic reasons but I have also read it was used as additional venting - venting what, exactly?
    All the drawings I have seen show smoke streaming from all four funnels but this is clearly 'Artistic Licence', however, in most photographs it is difficult to dismiss the fact that smoke appears to be coming from all four. Was some smoke diverted from it's neighbouring funnel in order to make it LOOK like a working unit?
     
  2. Brian O'Dell

    Brian O'Dell Guest

    I think the venting was to let steam out of the Kitchens or the heating system.
     
  3. Diego Uriol

    Diego Uriol Guest

    You are right Brian, the fourth funnel was used for the ventilation of the galleys, but it was also used for ventilating the turbine room (next to the reciprocating engines)

    Hope this helps,
    Diego
     
  4. Brian O'Dell

    Brian O'Dell Guest

    Yes, there were pipes in Kitchens which collected steam and the steam travelled upward and out of the funnel. A fan was suited inside the pipes to let the steam out quicker. There were also vents in the Kitchens which collected steam with a fan. The fan sucked in the steam and out of the smokestack.
     
  5. The fourth funnel was hardly "cosmetic." Even a nuclear powered Titanic, if it had the same hull/superstructure configuration and weight of machinery, would require the same size and weight of funnels even though nothing would go up their flues. The four stacks performed an important naval architecture function quite separate from venting spent combustion gas.

    The height, weight, and placement of those huge cylinders had everything to do with the stability and trim of the ship. Without them, Titanic would have exhibited too much transverse stability for passenger comfort. In sailor's terms it would have been "too stiff" and would have exhibited a "snap roll." All of that metal aloft helped reduce that snap roll to something more comfortable and less likely to induce sea sickness.

    Four funnels were absolutely necessary to spread the weight aloft along the full length of the ships midbody. Otherwise, Titanic would have exhibited a slight nose-down attitude, something that makes steering difficult and can result in taking excessive water over the bow in heavy weather.

    So, the big cylindrical stability controllers mounted above the boat deck were necessary for controlling the ship's stability/roll characteristics. I think it was rather clever of the designers to find other uses for them such as conducting the furnace gas up and away from passengers on the upper decks.

    As an aside, note the towering aluminum superstructures of modern passenger ships. What function do those layers of decks have with regard to stability? Could the ungainly stacks of decks on modern vessels have anything to do with their lack of four big stacks like Titanic?

    -- David G. Brown
     
  6. I thought that the primary function of the "dummy funnel" on the Olympic class ocean liners was to ensure a supply of fresh air to the engine rooms and boiler rooms (important for the efficient operation of the boilers). The galley flue was of secondary importance. In later years, when merchant vessels were adapted for oil firing, a dummy funnel might also provide an outlet for inflammable gases from the oil tanks.
     
  7. Bill West

    Bill West Member

    All that shows in the plans leading to the 4th stack is a round smoke pipe for the galley stoves, a vent duct for room air from the galleys and an open ventilating space rising from the turbine room.

    Bill
     
  8. Paul Rogers

    Paul Rogers Member

    The original plans for the Olympic Class ships included only three funnels, IIRC. I will try and dig out the reference for this over the next day or so, as I have some annual leave to take (although we really need Mark Chirnside to drop in on this thread).

    Although I'm sure that David Brown is correct re: the need for a fourth funnel for the final design of these ships, I believe that the initial decision to include an extra funnel was cosmetic, in order for the Olympic Class to appear as 'impressive' as the Cunarders, Lusitania and Mauretania. No doubt, the plans were then amended to incorporate the extra weight of a fourth funnel.
     
  9. Hi Paul,

    You are correct the original plans do only call for three funnels, the plans were amended mid construction of Olympic to include the forth funnel, and I believe you are correct that the decision was done to compete with the profile of the Cunard Four Funnelers.

    I rather think the Olympic Class look much more decadent with four funnels, three would look awkward IMHO.

    Best Regards,

    Brian
     
  10. Paul Rogers

    Paul Rogers Member

    Thanks for that confirmation, Brian. I agree with you; the Olympic Class ships definitely look 'right' with four funnels.

    I had a quick look through Mark Chirnside's and Dave Gittins' books to see if I could find a reference to the original 'three funnel' plans without major digging. Although I wasn't successful, Dave Gittins' book states as follows:
    Regards,
    Paul.​
     
  11. As I understand it, the boiler rooms each had their own ventilation systems that were seperate from anything the forth funnel could provide. Since they could all be sealed off from each other by way of the watertight doors, there wouldn't have been a lot of wiggleroom on the matter.
     
  12. There are some fairly well known plans which depict a cutaway section of a H&W ocean liner, probably the Olympic, and these clearly show intended function(s) of the dummy funnel. If anyone can confirm that these circa 1911 plans are out of copyright I will scan them for posting.
     
  13. For clarification, although three funnels may have been amongst the considerations early in the conceptual design process, there was never any need to "amend" the Olympic's plans, mid-construction or otherwise, to include the fourth funnel; this feature had been settled upon before the first piece of steel had been ordered from the mills. The initial design proposal which was approved for construction by the White Star Line had four funnels; a hand-colored inboard profile and G/A for the Boat Deck, initialed as approved by the principal parties during the summer of 1908, is reproduced in the endpapers of Michael McCaughan's "Birth of the Titanic." The arrangements of the ship's public rooms were changed somewhat from this approved design proposal -- for instance, a domed 1st Class Dining Saloon is shown -- as were the layout of some of the decks and deckhouses which comprised the superstructure, but the exact form of the hull, the arrangement of the machinery spaces and the major structural elements were all settled at this point, including the weights and disposition of those elements which would have a significant bearing on the ship's trim, stability and rolling characteristics.

    About the only significant design change concerning the funnels following the commencement of construction had to do with their average height; evidence left behind in the form of early photographs of the builder's model, and by the "ghosts" of the original outline of the funnels appearing on the Olympic's pre-WWI rigging profile, which shows something like a 9-foot reduction in height over the original proposal. While it's not impossible that the foreshortening of the funnels may have been an aesthetic change, this is unlikely. Particularly in those days, naval architects and marine engineers tended to be practical lot, so it is far more likely that the reduction in height was driven by something more fundamental, such as a need to alter the characteristics of the ship's righting arm rather than for the sake of appearance. (Personally, I think the funnels as built had a more pleasing appearance than that which would have resulted with the proposed taller ones.)

    Regards,
    Scott Andrews
     
  14. Folks, David Brown is right on with this one. That fourth funnel was not there just for cosmetics. That is a myth. The design choice was to either increase the size and weight of three funnels, or add a dummy fourth. The increase in ship size that evolved by 1911 meant that ships could develop severe motion problems unless they were fitted with relatively large funnels, including fake ones if necessary, which added weight high up away from the ship's center of gravity, which on the Titanic, was located down around F deck level. This tended to increase what is called the radius of gyration of the ship, which together with the added air drag of the funnel structure and bracing, helped dampen the ship's rolling motion. So in addition to keeping smoke and cinders coming up away from those on deck, those funnels added to comfort of those on board. Aesthetics were a secondary consideration.
     
  15. Paul Rogers

    Paul Rogers Member

    Well, one learns something new every day. Thanks, Sam.

    I'd still like to know (because I'm sad) exactly when the change from 3 to 4 funnels was made (if such a change was made) especially as the 'final' plans for the Olympic Class was: "Version D". (What was on "Version A", I wonder?) Assuming such a change was made, I'd also like to know the full reasoning behind it as Olympic could surely have been built with three funnels, as long as their size/weight also accommodated the requirements of ship design. After all, that's all she actually needed for her boiler room configuration.
     
  16. The Cunard vessels Lusitania and Mauretania had a large number of very prominent (and somewhat untidy) ventilators along each side, which were required to ventilate their engine rooms. This function was carried out, on the Olympic class, by the dummy funnels - the implication being that, if only three funnels had been provided, similar ventilators would presumably have been needed on the White Star liners. To that extent, the dummy funnels fulfilled an aesthetic, as well as a practical function, insofar as they contributed to the uncluttered appearance of the Olympic class vessels.
     
  17. Regarding ventilation of the boiler rooms, I thought that air was delivered to each compartment by a system of ducting. This diagram, which is presumably contemporary publicity material, shows the dummy funnel:
     
  18. Stanley,

    The No. 4 Funnel had absolutely nothing to do with ventilation of the boiler rooms. The boiler casings through which the funnels rose from the boiler rooms were transversely subdivided into several sections. The larger mid section contained the lower funnel, while the smaller forward and after end sections were further subdivided into two trunks each. The trunks at the very ends of the boiler casings were the stokehold ventilation trunks; each one terminated in a fan room located on F Deck. Each fan room contained two large Sirocco fans which supplied air through ducting which terminated in the firing aisle in front of each boiler. The trunks within the boiler casing sandwiched between the funnel casing and the stokehold ventilation trunks were the fidley trunks. In addition to acting as a conduit for plumbing and low pressure steam lines for the heating apparatus, the primary purpose of the fidley trunks were to act as an outlet for the hot air rising upward from the boiler rooms below. The stokehold fans were adjusted to supply air in somewhat greater volume than that required by the furnaces so that when combined with the natural draft created by the rising hot air in the fidley trunks, good circulation of fresh air was obtained throughout the boiler rooms. The screened inlets for the stokehold ventilation trunks are easily spotted and can be seen around the bases of the first three funnels in many photographs. The spilled gratings which were placed over the tops of the fidley trunks are harder to spot because they were flush with the top of the boiler casing surrounding the base of each funnel. These are most easily spotted in photos such as the one taken from the top of Olympic's No. 4 Funnel, and in overhead photos of the wreck.

    Regards,
    Scott Andrews
     
  19. The 'dummy funnel' seemed a common thing- I know the Normandie's aft funnel was a dummy, as was the Ille De France's.

    Of the 4 funneled ships- did any of the Cunarders have a dummy funnel?
     
  20. Tarn,

    No, all of the funnels on the Cunard four-funnel liners were connected to uptakes. The boilers on these ships were arranged in four boiler rooms, with each boiler room having its own funnel. The arrangement of the boilers and the configuration of the boiler rooms on these ships was substantially different from that aboard the Olympic-class ships, primarily due to the transverse space limitations imposed by the longitudinal coal bunkers.

    Regards,
    Scott Andrews