"Smoke floats" Topic

I know this seems like a really obvious question, but when making smoke how was this done?

I would assume that more oil was added to the fuel mix to create the thick black smoke, but I've read of 'smoke floats' – any idea what these were? And were they a supplement to creating smoke or were they the main method?

Ta,

Nick

Nick:

Could be the main method as used in Coastal Forces or as an addition to funnel smoke.

Good info here:

link

Joe

Smoke floats were in use as early as the Battle of Jutland by the Imperial German Navy – long cylinders that were tossed over the side, floated like buoys and produced volumes of smoke by chemical means for approximately 20 minutes. The Royal Navy also developed and employed chemical smoke generators fitted to small ships (DDs for example) and coastal craft. It was very dangerous stuff for the operating personnel, but it was nevertheless in widespread use. See the operations of the Dover Patrol and the great Zeebrugge raid for more detail. For WW2, the Battle of Sirte offers an excellent example and the IJN commonly made use of smoke in the night battles of the Solomons when they sought to disengage.

Screening by funnel smoke was performed by oil-fired warships (usually destroyers, but any oil-fired ship could produce a screen of sorts. It was accomplished by richening the fuel/air mixture to produce large amounts of oily smoke. A division of destroyers (3-4 ships operating in unison) was required to lay a really persistent smokescreen. The laying of such a screen required suitable weather and proper technique.

B

link

Fantastic information guys! I feel a gap in my knowledge has at last been filled – thanks very much.

Cheers,

Nick

I'm eleven months late with this but my understanding is that "chemical smoke" was produced by chlorosulphonic acid which created a thick white "smoke", which being cold remained at sea level. Smoke screens produced by funnel smoke being hot tended to rise and not give adequate cover at sea level. Ideally a smoke screen comprised a combination of the two methods.

I am sure other chemicals were used as well. Some of you whose schooldays are more recent than mine can probably recall other acids that react with salt to produce a dense gas.

Hi Pontius – The Naval Review archive contains two lengthy and informative immediate post-WW1 essays on the tactical aspects of smoke-screening. Wind direction relative to the enemy is most important in tactical terms, but wind speed, temperature and humidity play roles as well.

You are correct with regard to chemically generated "smoke". The screening particulates would be created as a function of a chemical reaction at a much lower temperature than funnel gases, hence would not have the same tendency to rise. Use of chemical "smoke" seems to have been pioneered by the IGN/HSF. The RN adopted it in the latter part of the war; photo evidence confirms its use by the RN in convoy and coastal operations (Zeebrugge, especially) – I do not know for absolutely certain if its was used by the GF, but would presume so.

Funnel smoke screens can be made to "lay down" more effectively than normal emissions. Smoke generated for screening is the product of purposely induced inefficient (i.e. – overly "rich") combustion conditions in the boiler; it emerges a little cooler than normal flue gases and is dense with relatively heavy unburned particulate matter. How fast this would cool off enough to "lay down" seems to be a function of outside temperature and humidity levels. Contemporary recommendations of the day were that four destroyers were required to lay a properly opaque and persistent screen. The web has various photo images of such screens whereby a fair impression of their behavior can be gained.

FWIW.

B

Cheers guys. As it happens I was chatting to my dad about this and he said, "oh, they make good chairs". They were bombed out twice in the Liverpool blitz so had lost most of their furniture. Fortunately my grandmother worked in a factory in Wallasey making smoke floats so some found their way home to stand in for tables, chairs, sideboards, etc.