Shipping out: My Experiences on a Commercial Tanker (PART I)

Texaco Minnesota was a T-2 Tanker built in 1943 as SS Churubisco (Hull No. 254) at Sun Shipbuilding & Drydock, Philadelphia, PA. It was a standard Maritime Commission T2-SE-A1 design. The ship engaged in the coastwise trade, carrying fuel oil from the refinery at Wilmington to paper mills in various ports in the Pacific Northwest. It would be in and out of homeport on roughly a biweekly basis.

The T-2 Tanker has to be considered as one of the world’s greatest ships. Along with the Liberty and Victory ships, they formed the backbone of the US Merchant Fleet during and after World War II. The most common variety was the standard United States Maritime Commission type T2-SE-A1. Between 1942 and 1945, 481 were built. The ships were 523’ long and had a full load displacement of 21,800 tons. They had a turbo-electric propulsion system rated at 6000 SHP. Service speed was 14.5 knots. The crew consisted of 38 persons, far less than a comparable naval vessel. A number of modified versions of the T-2 design served as naval fleet oilers during World War II. Some tankers remained in service under the Military Sealift Command well into the mid 1970s. Its naval service crews consisted of over 250 personnel.

In 1961, Texaco operated a fleet of twenty-five coastwise tankers, fourteen of which were T-2s. The coastwise fleet sailed under the U.S. flag because the 1920 Jones Act required that ships carrying cargoes between American ports be registered in the United States (still true today). The bulk of the Texaco coastwise fleet operated out of Port Arthur, Texas, carrying petroleum products of all types to ports in the Northeast. At the time, Texaco only operated two ships on the West Coast, the SS Texaco Minnesota and SS Texaco Delaware. I would end up serving on both ships, as well as the SS Texaco Washington, which operated on the East Coast. Texaco also had tankers in offshore trades. But these were all of Panamanian or Liberian registry.

A commercial ship was manned much differently than a naval vessel. In general, the crew was far smaller, but older and more experienced. The Captain of a merchant vessel is called the Master.  While the Commanding Officer of a U.S. Navy destroyer was usually between 35 and 40 years old, the Minnesota’s Master was in his sixties. The four licensed deck officers consisted of the Master, Chief Mate, 2nd, and 3rd Mates. There were four licensed engineers, the Chief, 1st, 2nd, and 3rd Assistants.  The Radio Operator and Chief Steward were also considered officers. The officers were not unionized, but the 25-30 unlicensed crewmembers belonged to the National Maritime Union (NMU).  The unlicensed personnel performed the duties prescribed in their union contract.  That was about all they would do. As an example, it was specifically stated that they were not required to blow boiler tubes. That duty was left to the watch engineer.

A major difference between a naval and merchant vessel is the position of the Chief Engineer. Aboard a naval vessel, he is a department head.  On a merchant ship, he ranks slightly below the Master.  He draws approximately the same pay and operates independently of the Master. In the officer’s mess, the Master sat at the head of the table and the Chief Engineer sat at the opposite end. The Chief Engineer of the Minnesota had many years at sea.  Like the Master, he appeared to be in his 60’s. He rarely came to the engine room. In general, the only time I saw him was when I delivered the Engine Room logbook or gave him a lube oil sample at noon. This organization would never work aboard a naval vessel, yet it works successfully on merchant vessels of virtually every maritime nation. On modern automated commercial ships, the Chief Engineer can monitor plant performance directly from a workstation in his stateroom.

The Chief Engineer was a non-watch stander. He had to come up through the ranks in order to achieve his position. The duties of the three assistant engineers aboard Texaco tankers were as follows:

• The First Assistant Engineer was in overall charge of the machinery spaces. He was assigned to the 0400-0800 and 1600-2000 watches. He also came down to the engine room to supervise during maneuvering watches.
• The Second Assistant Engineer was in charge of the fire room. He performed all of the duties assigned to the Oil King on a naval vessel, including responsibility for boiler water chemistry. He stood the midnight to 0400 and 1200-0600 watches in the engine room. His duties did not include responsibility for cargo operations, as these came under cognizance of the Chief Mate.
• The Third Assistant Engineer, which was my assignment, stood the 0800-1200 and 200o-2400 watches. He was required to relieve the First Assistant Engineer around 1700 for a half hour at dinner. Additional duties included the responsibility of maintaining proper levels of lube oil in all equipment plus daily cleaning of the lube oil purifier.  He also had that responsibility on gear driven ships without a full time electrician.

The three corresponding deck officers had the same watch rotation as the engineers. The Chief Mate was responsible for all cargo handling and deck seamanship operations. The Second Mate served as the ship’s navigator, while the Third Mate provided assistance to the Chief Mate. Anything outside of our watches was considered overtime, which we would receive extra pay at an increased rate.

The ship had a turbo-electric propulsion plant manufactured by General Electric. I had never been on a ship with this type of plant. The ship was propelled by a large electric propulsion motor, which received power from a main steam turbine-driven generator. Most ocean-going ships in the US Merchant Marine had geared turbine propulsion. Turboelectric propulsion was chosen because there was a shortage of gear manufacturing capabilities during the war. Actually, the T-2 propulsion systems which were manufactured by General Electric and Westinghouse had many features in common with the turboelectric propulsion systems aboard the Buckley (DE 51) and Rudderow (DE 224) class destroyer escorts that were built during World War II.

The system was AC-AC drive. Power was supplied from a single steam turbine directly to a 5400 kW 2300 VAC main generator that operated over a speed range of about 900 to 3600 RPM. The generator supplied power to a synchronous motor with a continuous rating of 6000 SHP at 90 RPM. Overload rating was 6600 HP at 93 RPM. It was directly connected to the propeller shaft. Power to the propulsion motor was supplied through manually operated contactors controlled by operating levers at the control cubicle.

Because the system operated at variable voltage and frequency, the main generator could not be used to supply auxiliary power, except when the ship was in port. In a modern integrated electric power system, the main generators are operated at constant speed and voltage, and the power to the propulsion motors is controlled by solid-state frequency changing devices. On systems of this type, the main generators supply both propulsion and ship service power.

Variations in propeller speed were controlled by varying the speed of the main turbine generator by means of the governor control lever at the propulsion control cubicle. The directional rotation of the propeller changed by closing contactors that effectively interchanged two of the three phase leads to the motor stator. Full power was available in both the ahead and astern directions.

A synchronous motor is not self-starting. During the starting period, the turbine was at idle speed. When the motor was ready to be synchronized, as indicated by flickering on the ammeter, DC field excitation was applied to the rotor and the generator excitation was reduced to normal. When the motor was “in step” with the generator, you could increase turbine speed. All steps during the starting process were controlled manually by the engineer. The generator had two poles, while the motor had eighty. This gave a speed ratio of 40:1 between the main turbine and propeller shaft. So the overall effect of the electric propulsion system was to act just like a reverse-reduction gear for the main turbine.

The main turbo generator was driven by a 10 stage single casing steam turbine. The maximum continuous rating was 5400 kW at 3715 rpm, 2370 volts, 3 phase, 62 Hz, 1.0 power factor. The generator was driven directly from the turbine by a solid coupling. The generator was mounted forward of the turbine. It was fully enclosed with a seawater to air cooler mounted on top.

The main thrust bearing, one line shaft bearing, the main feed pumps, and the stern gland was all located in the shaft alley. The stern gland was the old flax packing type you had to keep slacked just enough to keep a small stream of water running continuously to the shaft alley bilges.

Most of the auxiliary equipment in the machinery spaces was electric motor driven. Steam driven auxiliaries included:

• Two turbine driven main feed pumps located below the fire room in the shaft alley.
• One turbine driven forced draft blower that could be lined up to supply combustion air to either boiler. I never saw it used.
• One turbine driven fire & Butterworth pump. The ship operated with a dry fire main. The Butterworth system was used for tank washing.
• Reciprocating auxiliary feed and general service pumps.
• Most major deck machinery. This was in order to facilitate speed control.

Some other significant differences that existed between auxiliary systems aboard commercial and naval ships included:

• Gravity lube oil systems. All main turbo generator and propulsion motor bearings and the main thrust bearing were lubricated from overhead gravity tanks located high in the space. An advantage of this type of system was that it provided sufficient time to stop the propulsion machinery in the event of pressure loss from the main lube oil pumps.
• The deareating feed tanks were located high in the fire room, thereby negating the requirement for feed booster pumps.
• Steam at reduced pressure for feed water heating was provided from the main turbines by way of stop check valves. These were referred to as bleeder or extraction connections. These valves had to be closed during maneuvering and in port operations.
• There was only one distilling plant which was used to make boiler feedwater. Because of the small crew size, it was always possible to obtain sufficient potable water from pierside in order to support the crew.
• The ships burned “Bunker C” heavy fuel oil. A continuous supply of steam was supplied to heating coils located in each of the fuel tanks. The fuel supply to the burners had to be heated to 180° F. Cleaning fuel oil strainers was a very messy job.
• The main condenser seawater inlets were not fitted with scoop injection.
• The steering gear was electro – hydraulic with two motor driven pumps. Bridge control was by means of a hydraulic telemotor. There was no provision for quick changeover between power units. Our practice was to have both units on the line when entering or leaving port. Each power unit was fitted with manually operated valves. The steering gear room was never manned continuously when we were underway. It was only manned when testing the gear prior to getting underway and when placing the standby unit on or taking it off the line when entering or leaving port.

There were two auxiliary ship service generators. Each generator consisted of a steam turbine driving three generators through a reduction gear. From forward to aft, these generators were:

• 400 kW, 440-Volt AC Ship Service Generator.
• 75 kW DC exciter to furnish power to the field circuits of the main generator and motor.
• 55 kW, 120 volt DC generator that supplied power to the excitation bus for the AC generator.

Because of their long stack up length, these generators appeared to be as big as the main generator, at first glance. The gears emitted a high-pitched noise that would have been considered intolerable in naval vessels of later design. But none of us ever wore any type of hearing protection. There was an auxiliary condenser. But it was rarely used. The generators normally exhausted to the main condenser. All normal underway and in port operations were carried out on one auxiliary generator on line. For maneuvering in and out of port, we would bring the second unit up to speed and put it in a standby condition, without putting it on the line. At the end of every trip, we would parallel and shift generators.

On the lower level was a 2300/450-volt transformer for supplying AC power for the cargo and stripping pumps. There were three 200 HP cargo pumps and two 50 HP stripping pumps. The motors were located on the lower level at the forward end of the engine room and they drove the pumps by way of shafts through the bulkhead into the Pump Room, located immediately forward. These pumps were normally supplied with power from the main generator when the ship was in port. When the main generator was used for cargo pumping operations, it had to be brought up to the nearly full rated speed of 3600 RPM with some variation as requested by the cargo pump operator over the telephone. The pumping operations were a cooperative effort by the pump man and the watch engineer who had start-stop and speed control of the motors from a panel on the Main Switchboard.  Actual pump speed was controlled by the main turbine generator governor control lever. The watch engineer had to watch the pump motor ammeters which would drop to zero in the event of loss of suction.

None of the three Texaco tankers that I served on had an emergency diesel generator. There was a small 50 kW steam turbo generator in the after starboard corner of the engine room upper level. But I never saw it operated. We were just very careful never to put the lights out. In the event of a dark ship condition, it would have been necessary to supply Diesel fuel to one of the boilers by means of a hand pump.

The arrangement of the machinery spaces was somewhat similar to that aboard the Naval AD 37 Class Destroyer Tenders with the fire room aft of the engine room. It was not necessary to go “up and over”. Direct access between spaces was by hydraulically operated watertight doors which were normally left in the open position. The engine room had two levels. On the upper level were the main and the two auxiliary ship service generators. Across the front of the space was a very large Main Switchboard. The main control cubicle was located on the left side. On the lower level were the main and auxiliary condensers, main propulsion motor, various pumps, and other auxiliary machinery.

The fire room was located immediately aft of the engine room’s upper level. It was normally manned by a single fireman, even when entering and leaving port. It contained two oil fired sectional header boilers mounted side by side, which provided superheated steam at 435 psi and 725°F to the main and ship service generators. The boilers were provided with Bailey pneumatic automatic combustion control systems. These systems did not come into common use in the U.S. Navy until the early 1960s. Otherwise, the T-2 plants made no more use of automation than naval vessels of that era.
BOILERS
Each boiler was fitted with four oil burners. The burners were not of the wide range type. It was necessary for the fireman to cut them in and out manually in accordance with steam demand. When going from a STOP to a FULL ASTERN bell, for example, the fireman had to run across the firing aisle, cutting in as many as six burners. Boiler water level control was by a single element feed water regulator. The lone fireman was aided by the engineer who controlled acceleration and deceleration rates, and to some extent, the boiler water levels with the main turbine governor lever. This method of boiler control would seem very peculiar to operators of naval boilers of that era.

Unlike the boiler shown in the above illustration, the T-2 boilers were fitted with air preheaters rather than economizers. The preheaters had to be bypassed when maneuvering and during in port operations. The main and auxiliary steam stop valves were of the stop-check type, making it relatively easy to take a boiler off the line when necessary.

On all of the tankers that I served on, there was a placard on the Bailey boiler control board stating “Warning, Anyone Caught Making Unauthorized Adjustments to This System Will be Discharged in the Next Port.”

When I took over the watch, both boilers were on the line. The main turbo generator was idling and one of the two auxiliary generators was on the line supplying electrical power. All of the major auxiliaries were operating and a loud whine permeated the space. The common practice on these ships was to keep the plants steaming all the time, except during shipyard overhauls. As previously discussed, the main turbo generator was used to supply power to the electrically driven main cargo pumps when discharging cargo in port.