Model Boat Mayhem

Please login or register.

Login with username, password and session length.
Pages: [1] 2   Go Down

Author Topic: Smokestack toppers?  (Read 4748 times)

Pat Matthews

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 260
  • Get your boats wet!
  • Location: Temecula, Sunny California
    • Matthews Model Marine
Smokestack toppers?
« on: November 27, 2008, 02:59:11 pm »

Anyone know much about steamer smokestacks, and tops thereof?

It's one area we rarely see in photos, but which we giants in the model boat world see every time we look at a model. I'm building an Envoy, which of course comes with a wonderful GRP stack... but which is simply a wide open tube, as seen in this shot gratefully stolen from the Model Slipway site:



But I KNOW that's not all there is to it. The next couple shots illustrate the 1906 steam tug Hercules in San Francisco, where you can see that the stack is actually a sheathing around the actual chimney. In this case, the space between is wide open all the way to the top. Might Envoy's later technology be similar? Or somehow closed off? Would I expect to see any grating across it all?

TIA...

Logged
Pat Matthews
Get Your Boats Wet!
Matthews Model Marine

Bunkerbarge

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,370
  • Location: Halifax, UK
Re: Smokestack toppers?
« Reply #1 on: November 27, 2008, 06:36:23 pm »

Funnels are basically nothing more than aesthetics and don't do a great deal functionally apart from tidy things up and possibly direct some air flow.

What you see on the outside is 99% of the time simply a cladding that hides the uptakes.  In steam days you would have the boiler exhaust going through it and in diesel plant set ups you may have engine exhausts, all as a seperate pipe inside the funnel.  Many incorporate other items such as vents from tanks, crank cases etc, some include machinery space air exhausts and some will have steam plant relief valves venting to the top of the funnel.

In the case of the Envoy there would almost certainly be the boiler exhaust running up the centre as per your example but seeing as ventilation is via the cowls and there are external vents fitted there may well not be much else inside. 

Some vessels were fitted with spark arresters on the top to help prevent sparks from giving a ships position away which consisted of basically a steel framework but a lot of them were removed after they had rotted away and started to fall apart.

If you are going to fit a steam plant and you run the boiler exhaust up the funnel or if you are going electric and you decide to fit a water vapour generator bot will provide a convincing internal flue.  If not you could always insert a dummy tube to give the same effect.  I would then airbrush the whole area, inside and out, matt black to give a nice sooty effect.
Logged
"Dirty British coaster with a salt-caked smoke stack, Butting through the Channel in the mad March days"

Bryan Young

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 6,893
  • Location: Whitley Bay
Re: Smokestack toppers?
« Reply #2 on: November 28, 2008, 12:11:27 am »

Bunkerbarge...did your reply really answer the question? Or was the question how to make the cowl? A little confused. BY.
Logged
Notes from a simple seaman

Pat Matthews

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 260
  • Get your boats wet!
  • Location: Temecula, Sunny California
    • Matthews Model Marine
Re: Smokestack toppers?
« Reply #3 on: November 28, 2008, 12:16:02 am »

Well, my intent is to put a cylindrical tube up the middle of the model's stack, with some bracing not unlike in the worm's eye view of the Hercules stack. I won't bother with any grating. The annular area will be open- unlike a diesel stack, which is usually covered over completely except for an exhaust pipe or two coming out.

Just curious if this would be obviously wrong on Envoy?
Logged
Pat Matthews
Get Your Boats Wet!
Matthews Model Marine

Bunkerbarge

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,370
  • Location: Halifax, UK
Re: Smokestack toppers?
« Reply #4 on: November 28, 2008, 12:24:07 am »

I personally think that would be fine and pretty authentic.
Logged
"Dirty British coaster with a salt-caked smoke stack, Butting through the Channel in the mad March days"

Bunkerbarge

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,370
  • Location: Halifax, UK
Re: Smokestack toppers?
« Reply #5 on: November 28, 2008, 12:25:22 am »

Sorry Bryan, I thought I'd answered it, maybe I went off at a bit of a tangent.
Logged
"Dirty British coaster with a salt-caked smoke stack, Butting through the Channel in the mad March days"

victorian

  • Guest
Re: Smokestack toppers?
« Reply #6 on: December 01, 2008, 10:34:25 am »

Here's an unusual view of the cowls on 'Royal Sovereign' from a contemporary picture book called 'Queens Empire'.

You can click on the image for a much bigger (11 Mb) version.

This seem to support the idea that the visible funnel is just cladding.

Logged

farrow

  • Guest
Re: Smokestack toppers?
« Reply #7 on: December 04, 2008, 10:52:04 pm »

Pat looking at the first pic, I do not see the need to put a tube inside the provided funnel. As if you look at the top of the funnel the cowling covering both tubes is what you see there.
Logged

Jonty

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 852
  • Location: Hoselaw - facing The Cheviot (Scottish Borders)
Re: Smokestack toppers?
« Reply #8 on: December 06, 2008, 08:34:52 pm »

  Were not warship funnels baffled internally to hide boiler glow from aircraft?
Logged
I eat my peas with honey,
I've done it all my life;
It makes the peas taste funny,
But it keeps 'em on the knife.

farrow

  • Guest
Re: Smokestack toppers?
« Reply #9 on: December 06, 2008, 11:23:25 pm »

I would not thought that the Admiralty would go to great length with a tug, they were and still are a piso bunch when it comes to spending money, plus in a small vessel such as a tug there is not a lot of room spare I would have thought.
Logged

farrow

  • Guest
Re: Smokestack toppers?
« Reply #10 on: December 08, 2008, 11:21:34 pm »

Hi Jonty, I was thinking, with standard marine boilers you shouldn't get a glow to attract aircraft, because the boiler flame would be reduced to hot gas before it gets to the funnel flue. The only boilers I know which I know do show flames were the old upright scotch boilers fitted to the old Scots puffers, with them a coal fired boiler would regularly put flames several feet out of the top of the funnel, I have seen Vic 55 with a 4/7 ft flamer pass me some years ago in Loch Long.
Logged

Bunkerbarge

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,370
  • Location: Halifax, UK
Re: Smokestack toppers?
« Reply #11 on: December 09, 2008, 01:28:07 pm »

It's not the furnace flame you might be able to see, it is glowing carbon deposits that break away, usually after a sudden increase in load, that continue to glow as they pass out of the funnel.  You can get quite a significant shower of sparks especially from such a combustion process as a boiler in an old steamer which were notorious for poor combustion.

During daylight hours this isn't an issue as the black smoke gives the game away from many miles out but at night sparks from a funnel can be quite noticeable.
Logged
"Dirty British coaster with a salt-caked smoke stack, Butting through the Channel in the mad March days"

Bryan Young

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 6,893
  • Location: Whitley Bay
Re: Smokestack toppers?
« Reply #12 on: December 09, 2008, 05:38:52 pm »

It's not the furnace flame you might be able to see, it is glowing carbon deposits that break away, usually after a sudden increase in load, that continue to glow as they pass out of the funnel.  You can get quite a significant shower of sparks especially from such a combustion process as a boiler in an old steamer which were notorious for poor combustion.

During daylight hours this isn't an issue as the black smoke gives the game away from many miles out but at night sparks from a funnel can be quite noticeable.
I really ought to know better....but is that why you lot "blow tubes" at night? BY.
Logged
Notes from a simple seaman

farrow

  • Guest
Re: Smokestack toppers?
« Reply #13 on: December 09, 2008, 10:29:19 pm »

Could be that the engine room trying a crafty one, as when I was on a steamer, I always tried to lay the vessel across the wind. As the crap that comes out is unbelievable and when it lands inboard it is a devils job to get rid off.
Logged

Bunkerbarge

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,370
  • Location: Halifax, UK
Re: Smokestack toppers?
« Reply #14 on: December 10, 2008, 03:26:31 am »

It's not the furnace flame you might be able to see, it is glowing carbon deposits that break away, usually after a sudden increase in load, that continue to glow as they pass out of the funnel.  You can get quite a significant shower of sparks especially from such a combustion process as a boiler in an old steamer which were notorious for poor combustion.

During daylight hours this isn't an issue as the black smoke gives the game away from many miles out but at night sparks from a funnel can be quite noticeable.
I really ought to know better....but is that why you lot "blow tubes" at night? BY.

Just one of those traditional things I think.  The 12/4 night watch usually have a quiet time so that may be one reason as well as not wanting to make horrible black smoke in daylight.  I always used to give the 2nd mate a shout though and he would get the wind across the deck for half an hour while I did it.  we used to take a lot of pride in such things in those days, technique being very important as well as keeping the steam valves in good condition by regular painting with black oil and graphite.
Logged
"Dirty British coaster with a salt-caked smoke stack, Butting through the Channel in the mad March days"

Bryan Young

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 6,893
  • Location: Whitley Bay
Re: Smokestack toppers?
« Reply #15 on: December 10, 2008, 05:52:49 pm »

Like many "fisheads" I have been a victim of some idiot not calling the bridge before blowing tubes...and with a following wind the result is catastrophic...must have been dreadful on a large passenger liner heading eastwards across the N.Atlantic! BY.
Logged
Notes from a simple seaman

Jerome Morris

  • Guest
Re: Smokestack toppers?
« Reply #16 on: December 10, 2008, 09:11:25 pm »

Something else I've seen, is the topper was attached to the exhaust uptake. Just below the top edge of the uptake there were a series off 2" holes, I assume to permit the passage of air which would be created by the vacuum of the exhaust smoke.
Logged

farrow

  • Guest
Re: Smokestack toppers?
« Reply #17 on: December 10, 2008, 10:43:49 pm »

In the Royal Navy it was exhaust gas, if there was smoke seen from the bridge the duty MEO would be called and told to stop making smoke. The RN considered smoke was the product of poorly set up burners in the boiler, there for wasting fuel.
Logged

BarryM

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,692
  • Location: West Lothian
Re: Smokestack toppers?
« Reply #18 on: December 11, 2008, 08:51:17 am »

A slight haze at the funnel top was encouraged as indicating good combustion; this was usually referred to as an 'economical haze'. 

Even when no smoke was visible, the funnel would always be discharging the boiler exhaust. I recall an irate Old Man phoning down to complain during the wee small hours that he and the bridge watchkeepers were being gassed by smoke. Having checked, I was able to inform him that there was definitely no smoke from the funnel - just the normal uptake gases. The weather conditions were blowing the uptake gases down and for'd over the bridge and there was nothing I could do to change that except shut down the boilers. (Not a practical proposition.) After much mumping, he changed course and I was left in peace to brood on an unannounced tube-blowing session.  >>:-(
Logged

farrow

  • Guest
Re: Smokestack toppers?
« Reply #19 on: December 11, 2008, 10:23:06 pm »

I was refering to smoke not haze from from the funnel, when I was an engine fitter apprentice(to many years ago to remember) at Chatham Dkyd, we were shown a RN training film about combustion in boilers and setting up the burners etc. The thing that I remember most was that there should be no smoke be it black or white in the exhaust gas, as this was a sign of poor combustion. The film showed a destroyer slamming along at a fair rate and the only thing you saw coming out of the funnel was a strong heat haze no coloured smoke, this was stressed in the film how a funnel exhaust should be. But bear in mind the RN employs alot more staff in the engine room than the Merchant Navy ever does, plus alot of the staff employed in the engine room by the RN are more specialist trained in certain areas than the average merch stoker.
Logged

BarryM

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,692
  • Location: West Lothian
Re: Smokestack toppers?
« Reply #20 on: December 11, 2008, 10:45:58 pm »

I was refering to smoke not haze from from the funnel, when I was an engine fitter apprentice(to many years ago to remember) at Chatham Dkyd, we were shown a RN training film about combustion in boilers and setting up the burners etc. The thing that I remember most was that there should be no smoke be it black or white in the exhaust gas, as this was a sign of poor combustion. The film showed a destroyer slamming along at a fair rate and the only thing you saw coming out of the funnel was a strong heat haze no coloured smoke, this was stressed in the film how a funnel exhaust should be. But bear in mind the RN employs alot more staff in the engine room than the Merchant Navy ever does, plus alot of the staff employed in the engine room by the RN are more specialist trained in certain areas than the average merch stoker.

Yes, I remember a Grey Funnel type being amazed that we could run 32,000HP plus auxiliaries with only three watchkeepers per watch. We also  managed to produce efficient combustion without the specialist training of the RN! If three MN can do the work of 30+ RN, who are the better trained?  %)

Barry M
Logged

Bryan Young

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 6,893
  • Location: Whitley Bay
Re: Smokestack toppers?
« Reply #21 on: December 12, 2008, 07:17:08 pm »

One of the reasons that the RFA keeps going without being taken over by the RN is that "man for man" the RFA is more efficient.
My experience of RN "courses" is that individuals are too wrapped up with their own speciality and this gives rise to the "nothing to do with me,guv" mind set, whereas the MN mindset has (generally) been aimed towards the well being of the ship as a whole.
Logged
Notes from a simple seaman

farrow

  • Guest
Re: Smokestack toppers?
« Reply #22 on: December 13, 2008, 04:42:15 pm »

What I have experienced of the RFA is that it is more pusser than the RN, The Stena Sea spread was run by stena in the Falklands for the RN with 21 crew, the RFA renamed it as Dilliegence and manned it with 45 crew!!!!!
Logged

BarryM

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,692
  • Location: West Lothian
Re: Smokestack toppers?
« Reply #23 on: December 13, 2008, 06:24:48 pm »

.....on the other hand, two Seaforth PSV were taken over by the Admiralty for Falklands duties. The first thing they did was to build on two additional messes and accommodation and then up the manning from 10 to 34. My Lords also frowned on the use of the bow thruster on the grounds that it was unseamanlike..

Logged

Bryan Young

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 6,893
  • Location: Whitley Bay
Re: Smokestack toppers?
« Reply #24 on: December 13, 2008, 07:12:54 pm »

Both of the last postings are quite valid....insofar as it goes.
"Diligence" was converted from her mercantile role into a forward defence repair and maintenance vessel. In such a role she acts as "home" to both surface and sub-surface vessels (including "nukes"). These roles are quite obviously way and beyond the capabilities and knowledge of the usual mercantile crew. So she was re-equipped with all the wherewithall to support RN ships within the bounds of a floating dockyard. That takes people. They need accommodation. They need leisure facilities. As do the ships that come to her for sustenance and repair. Are you really saying that crew members of a sub should not be allowed a couple of nights in a comfortable bed?
Shame on you. You evidently have not thought this thing through.
Then....who feeds the visitors from a "dead" ship? One man and his dog in the galley? Of course the blasted ship was enlarged! It had to be.
The same thing applies to other ships taken up by the RFA from commercial outfits. The needs of the Navy and operational requirements generally mean that the ship and its crew are (when they are in a "war zone") in a 24 hour work cycle. Not just doing day-to day jobs, but operating flight decks, manning defensive weapons and all that sort of stuff.
So please don't try to belittle what goes on when you don't really know. All that does is to cast unwarranted doubts.
Sorry for the rant, but a little education for non mariners is sometimes required!. Sorry, cheers, Bryan.
Logged
Notes from a simple seaman
Pages: [1] 2   Go Up