Boiler Flat Ballet


By Richard H. King, CDR USNR-Ret.

At the time of this story, CDR King was LT JG, Main Propulsion Assistant (1965-1968), 
(Assistant Engineering Officer for Main Propulsion) 

    On modern gas turbine ships, the engine speeds and prop pitches can be controlled remotely from the bridge.  When docking such ships, the Conning Officer’s commands are instantly converted into a response at the propellers.  That is not the way it was on a Gearing Class Destroyer, the Navy’s last destroyers with 100% manual control.

      In Gearing Class engine rooms, the action in docking was at the throttle board where there was a big valve wheel that controlled the steam to the ahead turbines (high pressure “HP” and low pressure “LP” geared together), and a smaller wheel that controlled the steam to the astern turbine blades inside the LP turbine.  Typically the throttles were controlled by an E-3, sometimes an E-4 for special sea details.  The starboard shaft was driven from the forward engine room and forward throttle board, the port shaft from the after engine room. Each of the two “throttle men” were concerned only with his respective turbines and shaft.

      Assume that a shaft is turning ahead one third and the annunciator suddenly “clangs” and switches to “astern one third”.  The throttle man would immediately crack open the astern valve and then close the ahead valve as fast as he could.  Then he would quickly switch his hands to the astern valve and open it some more.  Using a mirror mounted so he could see the “barber shop” stripes painted on the shaft, when the shaft stopped he would then open the astern valve in earnest until the shaft was turning backwards at the proper number of rpm’s.  Of course during a docking these orders from the bridge would come in fast and furious, sometimes faster than he could keep up. As a general rule of thumb, the experience level of the conning officer was inversely proportional to the number of commands it took to dock the ship (i.e., a more experienced conning officer could dock the ship with fewer commands). 

     The action in the engine rooms during docking, however, was nowhere near as exciting as the action in the boiler rooms.  One reason for this was the turbine set-up.  “Ahead” steam entered first the HP turbine and upon exiting there next went to the LP turbine.  Between those two turbines, there were many, many turbine blades.  For “astern”, there were simply a few blades on either end of the LP turbine set backwards from all the rest.  The “astern” valve shot steam directly to those astern blades.  Consequently, it took two or three times as much steam to go “back one third” as it did to go “ahead one third”. 

      As the conning officer yo-yoed between ahead and astern commands trying to maneuver the ship along side the pier, his orders were also “annunciated” in the fireroom.  The protocol (at least on Chevalier) was that everyone in the fireroom who heard the “clang” and/or saw the arrow jump to a new position would yell out the new command as loud as he could “back one third!  On the “boiler flat” (the lower level between the two boilers), it was time to get busy.  For an “astern” bell, the burner man (under the watchful eye of the top watch) would need to cut in some more burners as fast as he could. He had a pressure gauge in front of him, which he had to hold as close to 600 PSI as possible.  At 610 PSI he was going to start blowing safety valves and at about 590 PSI, he would be approaching a phenomena called “dragging down the boiler” and a total loss of control.  

      The top watch himself was also busy; he needed to speed up the forced draft boilers to greatly increase the amount of air to the boiler to match its sudden increase in firing rate (and avoid making smoke).  By looking through a periscope (the business end of which was in the stack) the top watch could observe how smoky it was and the color of the smoke.  Black smoke meant “not enough air” and white smoke meant “too much air”.  A clear or almost clear stack meant “just right”.  The periscope was the top watch’s primary indicator if he was feeding the boiler the right amount of air although there was also a gauge showing the air pressure in the boiler casing. Really experienced men could also match the sound (the “pitch of the whine of the blowers”) with a bell order.

      Especially when a klutz OOD (like the author of this article) was trying to dock the ship, the “bells” came fast and furious; “Ahead!  Stop!  Back!  Ahead!”.  The antics on the boiler flats became almost a form of dance as the men controlling the boilers tried to keep up.  Some BT’s were better and more skillful at this “art form” than others, and it was exciting and fun to watch real pros in action, doing the “Boiler Flat Ballet”.


Please note: The two boiler rooms, the two engine rooms, two emergency diesel generator rooms, various small pump rooms, the shaft alleys, fuel and water tanks, machine shop, electrical workshop, shipfitter's shop, engineering log room, Oil King's Shack, engineering berthing compartment, the stacks, ventilation blower voids etc, were considered "Snipe Country". This only applied to FRAM Destroyers!

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