How2 Drive A Sub

How to Drive a WWII Fleet Submarine

Some months ago I began working with a screenwriter as a technical advisor. He was doing a script as a book about a WWII-era adventure involving some civilians needing to escape as the Japanese invade Luzon, the Philippines. It is early December, 1941. Their only sea-going resource is an apparently recently ’abandoned’ fully operational pre-war fleet boat, left mysteriously with torpedoes in the tubes and provisions in the galley pantry when its crew was bloodlessly captured. The group is led by a retired Chief Electrician’s Mate, who was once a Chief of the Boat (COB) aboard the USS PORPOISE.

The Chief, being an EM and a former COB, has a working knowledge of the major functions and equipment to power, move, steer, dive and surface the boat, as well as setting up to charge batteries and run the compressors. The U.S. military has recalled him, field commissioned him a lieutenant, and ordered him to rescue the civilians and take them to Australia, also thereby retrieving the submarine, of course. Their only hope is to provision for a month-long voyage and make their way on the surface to their destination by Christmas while avoiding the blood-thirsty Japanese imperial navy along the way.

To accomplish his mission, our new lieutenant will have to train a handful of his charges to perform such tasks as running the main motors that drive the propeller shafts, shutting hatches, charging batteries and steering the helm. It’s not going to be easy, even though a few of his "crew" will turn out to be quite mechanically adept.

The Boat

USS SEARAVEN (SS-196)USS SEARAVEN (SS-196)In December of 1941, over 40% of the U.S. submarine force was in the Atlantic. The rest were either somewhere in the Pacific or Asiatic theaters. The fleet consisted of a mix of O-, R-, S-, PORPOISE- and SARGO-class boats, plus about a dozen brand-new TAMBOR class boats, about 112 in all. Only about 73 were afloat, the rest in various states of repair and refitting.

Many of the older boats were in the Phillipines, mainly at Cavite. For this reason I chose to assume our boat was a later SARGO-class, similar to the USS SEARAVEN (SS196) which really was based in Cavite. Another reason was that the surviving operational information applied to boats newer than the USS PERCH. It was safe to assume that boats made after that would not deviate much. They all were about the same length of roughly 310 feet, had four main engines with generators, a conning tower attack center, and two batteries of 126 cells. The main motor controls were also very similar among the PERCH and later classes, although some were ’split,’ having separate port and starboard controllers.

Propulsion Controls

Propulsion Control CubiclePropulsion Control CubicleMost fleet boats had a single propulsion control center, called the ’cubicle.’ It was a metal cage surrounding a complex system of lever-actuated heavy duty switches for connecting the 1500 HP main electric drive motors to either the batteries or the 1145 KW diesel-driven generators.

The controllerman stood facing a slotted control stand with ten vertical levers like baseball bats in a rack. Two central levers selected which battery (or both) to use and whether to use the batteries or generators for power.

The outside two levers on each side selected "AHEAD" or "ASTERN" direction, and controlled the start up and operating speed of the port and starboard main motors.

The remaining four levers connected the four diesel generators individually to either the batteries for charging or directly to the motors for propulsion, in any combination of the two.

The switching levers all had a home or "OFF" position near the center of travel. They also had latches or thumb buttons which release them to be smartly shoved or jerked to discrete detented positions. Moving them slowly caused arcing damage to the electrical contacts and was discouraged. "DON’T DO THAT!" Above the levers were four rheostats that insert resistance into the generator field circuits to limit current and adjust generator loading.

On the left and right of the console, near the motor reversing levers, were two rheostats that control the field current of each propulsion motor. Their purpose is to limit the motor field currents while switching, and also vernier control of motor speeds. For instance, when the reversing levers are set to AHEAD and the starting levers are in the SER3 (or running) positions, the motor rotation speeds can be adjusted for a given RPM range to achieve the desired boat speed.

The SARGO-class boat in our story had a maximum motor rate of 280 RPM, corresponding to FLANK speed of around a maximum of 18 or 19 knots. STANDARD speed would be about 15 knots with one-third being 5 knots and two-thirds 10 knots, respectively. Full speed would be something in between STANDARD and FLANK, perhaps 16 or 17, with the controllerman watching the current loads and motor temperatures to prevent overloading the electrical equipment.

In the photo you can see the large brass-framed motor rotation speed indicators (RPM tachometers) in the upper right and left. Below them are the MOTOR ORDER TELEGRAPH boxes that receive signals from the helmsman’s similar boxes on which he sets the indicators in response to speed change commands given by the Officer of the Deck (OOD). The helmsman responds "Answers all ahead two-thirds." when the controllerman matches his indicators. "Very well," acknowledges the OOD.

(Photos courtesy of the Pampanito Maritime Nat’l Park, San Francisco.)

Let’s Move It!

Main Motor Control Lever Settings for Ahead One Third SpeedMain Motor Control Lever Settings for Ahead One Third SpeedOpen and refer to the diagram at right.

Assuming all levers are in their "OFF" positions, here is the procedure for getting underway on both batteries for "ALL AHEAD ONE-THIRD" speed: (NOTE: ’forward’ means away from you - toward the forward end of the boat; ’back’ means toward you, or toward the stern.)

  1. Rotate both PORT and STBD motor field rheostats counterclockwise to 25%.
  2. Shove the BATT SELCT lever all the way forward to BOTH BATT.
  3. Pull the BUS SELCT lever all the way back to SLOW.
  4. Push both PORT and STBD MOT REV levers fully forward to AHD.
  5. Pull both PORT and STBD MOT STR levers back to the SER1 positions, watching the motor surge currents -- when the surge fades, pull the levers to the SER2, and when the surge again fades, to the SER3 positions. This is the positions for continuous running at slow speeds (one-third and two-thirds).
  6. Adjust the motor field rheostats for about 70 RPM shaft speed for one-third, or 140 RPM for two-thirds speed.

On the OOD’s command and helmsman’s signal to "ALL STOP," just operate the levers all in the EXACT reverse order to stop the propeller shafts.

There -- you’re well on your way to qualifying as a Controllerman! (At least according to the instructions in the Fleet Submarine Manual, and as near as I can remember from my qualifications days back in 1964.)



Conning Tower Main Steering StationConning Tower Main Steering StationOf course, once the boat is moving it’s important to steer it clear of obstacles and other vessels on the way to our destination. Ultimately the Captain, acting through the Officer of the Deck (OOD), is responsible for determining what course to steer. The Captain, on orders from HIS superiors, sets the ’big picture’ by writing the destination in the Order Book. The Quartermaster and Navigation Officer plot the course (series of successive compass headings). When the Captain approves the route, the initial course eventually gets to the Helmsman of the Watch who actually moves the rudder, sort of like a standing-up chauffeur. We do this in the Conning Tower at the Main Steering Station (I say ’main’ because there is an ’Auxilliary’ Steering Station below on the forward bulkhead of the Control Room).

The steering station controls the rudder angle and passes speed commands to the Maneuvering Room via Motor Order Telegraphs. The helm is a 3-foot wheel that operates a hydraulic system to alter the boat’s rudder angle. The rudder angle is displayed on the Rudder Angle Indicator. Rocking the wheel slightly to the right moves the rudder to the right. Since it is in the stern, that moves the stern to the left, causing the boat’s bow to point right. So turning the boat is like driving a car -- to go to starboard, rock the wheel to starboard. To go to port, rock the wheel to port. When you are on course, center the rudder.

Above the wheel is the Gyrocompass Repeater which indicates "true" course heading as determined by the Gyrocompass under the Control Room table, below. True course heading is geographic heading as opposed to magnetic heading which is subject to local variation errors due to... well, nevermind. Anyway, there is a backup magnetic compass higher on the bulkhead above the gyro repeater in case the gyro is disabled due to depth charge attack, or something.

The helmsman can’t see where the boat is going, so steering is essentially performed "in the blind." He only steers an ordered course using the rudder. The OOD commands steering changes via shouting orders down the Conning Tower Bridge Hatch such as "Come right to zero-niner-zero." Or "Right standard rudder, come to zero-niner-zero." ’Standard’ rudder is usually 15 to 20 degrees of rudder angle. Full rudder is 35 degrees. If there is imminent danger of collision ahead, he might scream "RIGHT FULL RUDDER!!! COME TO ZERO-NINER-ZERO!!!"

Main Steering Station LabeledMain Steering Station LabeledSometimes steering commands will also include speed changes, such as "All ahead two-thirds." When the OOD calls down a new speed, the helmsman acknowledges it and passes it on to the Maneuvering Room Motor Controllerman of the Watch by turning a knob on the MOTOR ORDER TELEGRAPHS. That moves a little red indicator on the dial, and another one on an identical telegraph in Maneuvering. When the controllerman receives the signal, he turns a knob on each of his telegraphs to move his black indicator to match the red one, thus confirming he got the message. While underway at sea, most commands will apply to both motors, the OOD using the word "ALL" in his command. Maneuvering in port to dock or undock the boat, or under special conditions where quick turning is desired, the OOD may give separate commands for each of the "PORT" and "STARBOARD" motors.

When the boat has steadied up on the new course, the helmsman is responsible to keep the boat on the commanded heading. Depending on the wind and sea direction, as well as the speed of the boat, this can be tricky to keep a straight line of travel. The rudder is a relatively small part, and the submarine is a long, almost solid hunk of steel that barely floats. WARNING: If the boat’s wake shows a "zig-zag," the Captain will be upset with the OOD, and the OOD will surely be upset with the driver.

(Photos courtesy of the Pampanito Maritime Nat’l Park, San Francisco.)


Last modified: 26Oct2019