Warship Wednesday, May 10, 2017: ‘All Vessels: Make Smoke!’
Here at LSOZI, we are going to take off every Wednesday for a look at the old steam/diesel navies of the 1859-1946 time period, and one of the most interesting tasks of a bygone era was that of making smoke, on purpose.- Christopher Eger
Warship Wednesday, May 10, 2017: All Vessels: Make Smoke!
“The signal from the Admiral’s flagship. The sharp blasts of his ship’s whistle have indicated the approach of enemy aircraft in force. Almost immediately plumes of whitish smoke arise from all ships of any size in the anchorage. Speedy small craft race among them with smoke pots pouring out a thick screen. Beach battalion men get their pots going and presently all the waterfront operations will be swathed in a dense opaque fog to confuse and disrupt impending bombing.”
One of the most popular tactics for early steam navy forces was the newfound ability to make instant smokescreens, either by ordering the stokers to burn cheap coal in designated boilers; constricting the air flow to the boilers and thus creating billows due to the choking flame; or by adding oil to the coal or funnel. This common tactic was a hit by the turn of the century, with Edwardian/Great White Fleet era ships– destroyers in particular– practicing it regularly.
By the end of the Great War, aircraft delivered smoke screens had been added to the lexicon as had purpose-made smoke generating devices.
This opaque white chemical smoke (titanium tetrachloride) was generally more effective than the sooty black boiler smoke of the Great War age, which tended to dissipate rather quickly. By the 1930s, the U.S. Navy used three different recipes for smoke: HC or hexachloroethane type smoke mixture, FS or sulfur trioxide in chlorosulfonic acid, FM or titanium tetrachloride, and WP or white phosphorus.
Aircraft used for smoke screens would be fitted with the Mark 6 Smoke Screen tank (50 gal.), weighing 593 lbs. when filled with 442 lbs. of FS, which was capable of ejecting smoke for 15 to 50 seconds. Chemical smoke from aircraft, 1920s:
WWII saw perhaps the most extensive use of smoke screens by naval forces, especially on daylight littoral operations such as amphibious assaults.
During WWII, besides funnel smoke and smoke generators, the Navy used both the Mark 1 and Mark II Smoke Float, devices which were 165 lbs. when filled with 90 lbs. of HC. They were 30.7″ high by 22.5″ in diameter and produced smoke for 18 – 21 minutes for the protection of convoys against submarines. There was also the Floating Smoke Pots M-4 and M4A1 (13″ high by 12″ in diameter and weigh 35 lbs. when filled with 26 lbs. of HC. They generate smoke for 10 – 15 minutes and are designed for amphibious operations) as well as smaller M-8 Smoke Grenades and 5″ smoke projectiles (using WP).
A US destroyer lays a heavy black boiler smoke screen off the coast of Licata during World War II:
PT boats were standardized with the standard Mark 6 generator which used a commercial ICC-3A480 full spun steel Mk 2 ammonia cylinder tank with a capacity of about 33 gallons, filled with FM or titanium tetrachloride. German S-boats ran a similar setup.
Although radar basically ended the usefulness of smoke screens in fleet vs. fleet operations, or in shielding a landing craft from a non-optically guided missile, fleets still practiced the maneuver well into the 1950s.
And, of course, it still has usefulness today when it comes to kicking in a door by a maritime landing or raiding force and you are trying to shield incoming waves from the Mk 1/Mod 0 eyes of a machine gun nest or RPG operator.
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