Model Boat Mayhem

Mess Deck: General Section => Full Scale Ships => Topic started by: g4yvm on October 09, 2018, 05:55:45 pm

Title: Smoke stacks question...
Post by: g4yvm on October 09, 2018, 05:55:45 pm
Stupid, but...


Ships stacks are canted aft presumably to help create a rearward flow of air even when stationary and so move the gasses and soot away from the vessel.  Right??


Is there an optimum angle therefore?


D
Title: Re: Smoke stacks question...
Post by: Colin Bishop on October 09, 2018, 06:09:52 pm
Not necessarily correct. Many stacks are not in fact canted aft, especially on modern vessels. Other methods are used to carry the exhaust gases clear of the ship such as windscoops and other airflow directing devices.
Older warships often had canted stacks to keep smoke, fumes and heat away from the masthead control positions in front of them. Some passenger and other vessels had/have sloping stacks for simply aesthetic reasons to improve appearance but modern naval architects don't seem to bother much with that these days.
So there is no standard practice or angle.

Colin
Title: Re: Smoke stacks question...
Post by: g4yvm on October 09, 2018, 06:17:51 pm
Thanks Colin.


D
Title: Re: Smoke stacks question...
Post by: derekwarner on October 09, 2018, 08:44:01 pm
Colin is certainly correct here....Warships used this canting method to keep soot away from communications mast locations [especially where manned Crows Nests were installed]....later Radar antenna and such also benefited in a similar manner


The velocity of air/wind passing over an orifice [chimney top] of given surface area, is the same for a vertical chimney or a canted chimney


Derek   
Title: Re: Smoke stacks question...
Post by: Mastermis on November 15, 2018, 08:56:51 am
Not sure about this, how much more information?
Title: Re: Smoke stacks question...
Post by: justboatonic on November 19, 2018, 12:31:17 pm
Interestingly, HMS Sheffield had funnel 'ears' to defect exhaust heat etc away from the ship's radar. Tests showed this was not needed hence why she was the only Type 42 in the RN to have them.

Argentina's T42's, the Hercules and Santisima Trinidad, the only Type 42 built outside the UK, did have them though.
Title: Re: Smoke stacks question...
Post by: derekwarner on November 19, 2018, 07:21:04 pm
Was Sheffield the first of her Class?......if and then so the original design detail & Drawings would have included the funnel ears


The design when sold to Argentina would have included the same & it would have been a very brave  ;) Argentinean Admirals decision to tell his Government that the Plans & Drawings just pair for were wrong

Their Navy were probably too busy reading up on the vessels offensive missile system[/size] [/size]...... Derek
Title: Re: Smoke stacks question...
Post by: justboatonic on November 19, 2018, 07:32:19 pm
Was Sheffield the first of her Class?......if and then so the original design detail & Drawings would have included the funnel ears


The design when sold to Argentina would have included the same & it would have been a very brave  ;) Argentinean Admirals decision to tell his Government that the Plans & Drawings just pair for were wrong

Their Navy were probably too busy reading up on the vessels offensive missile system...... Derek
Sheffield was being built at the same time as the Hercules.  The shipbuilders took part of the Hercules hull to repair Sheffield after an explosion damaged it and killed 2 ship workers.
Sheffield was launched in June 71, the Hercules in October 72 with the Trinidad in November 74 so yes, the Sheffield was the first in her class and first Type 42 in the RN.