Construction of Ship's Funnels - pre 1900

[Khephre]

Not quite sure whether this is the most appropriate section of the forum to post this particular query ...

In all of the plans for paddlers that I've looked through I don't recall ever seeing any detailed plans for late 19th century funnel construction on steam coasters or larger paddle ferries.

I know that funnel straps/bands and caps are usually shown on plans, but have never seen the plating arrangement for example.

So how were they made ?:
* were they rolled plate sections or complete rolled one-piece tubes
* If they were sections stacked one atop another, were they rolled into complete rings or were they part-ring plates that were lapped and rivetted together to form complete rings?
* If they were rivetted together to form complete rings. were the lap joints always at the rear of the funnel, or were they on either side, alternating port and starboard from one ring to the next?

Any suggestions folks?

cheers
Tony

[derekwarner_decoy]

Hi PD's - Tony... I did not know the answer so asked an old SALTDOG engineer who served his apprenticeship on 2000 ton up & downers on the Australian coast during WWII


So how were they made ?:
* Yes, they were they rolled plate sections
* Yes  the sections were stacked one atop another
* Yes they were rolled into complete rings and butted together
*The butted hoops/sections were riveted to a reinforcing vertical plate
* The hoop/sections were butted together in the vertical plane and riveted to horizontal reinforcing rings

It appears that the most economic form of construction was to have the vertical reinforcement plates as a near continuous riser & so reported all vertical joints as at the FWD end of the funnel?? - I don't know why :?:

This is but one example from an elderly man's memory - I am sure there would have been many variations   .....Derek

[Khephre]

Hiya Derek, I really appreciate your efforts and speedy response. Many tks mate.

Isn't it curious about how so much knowledge is developed over time in such mundane but specialised subjects as fabricating a funnel for a steamship, and then is lost again as technology moves on....

best regards
Tony
Auckland, NZ

[derekwarner_decoy]

Hi PD's -   -- when I re-read this it should have noted that the

'reinforcing vertical plate and the horizontal reinforcing rings' were internal    

Yes Tony... the only memory of a steam up & downer was the day my father lifted his 7YO son on his shoulders so I could see the mighty steam engine of the Manly ferry "South Steyne"   ....& that is a long time ago....but I still remember .......Derek  

[Khephre]

Hmmm... the South Steyne. What a ferry she was. Isn't she berthed at Darling Harbour now, working as a floating restaurant?

One final question on funnels construction :

Does anyone know when it became common to encase funnels?

I believe that the early funnels venting smoke and exhaust gases from the boiler would become so hot that paint would scorch off. Eventually they were encased with an outer funnel casing to create a space between the funnel-proper and the funnel casing.

Many tks
Tony