Starting rms TITANIC from cold

rms TITANIC, 1911, Cold Starting

WHITES STAR LINE Ltd., Builders: HALAND & WOLFF, Belfast
by Stephen Carey, engineer, editing by Earl of Cruise

rms TITANIC, 1911 © Stephen Carey 

Table of Contents

1    Overview of machinery spaces
1.1       Boiler rooms
1.2       Coal bunkers

1.3       Propulsion engines
1.4       Electrical power generation
1.4.1           Main generating sets
1.4.2           Emergency generating sets
2    Lighting up the boilers
2.1       Steam line redundancy
3    Starting the generators
3.1       Auxiliary seawater pump and condenser
3.2       Starting an emergency generator
3.3       Starting the main generators
4    Starting main engines
4.1       Main seawater pumps
4.2       Main air pumps (dual system)
4.3       Main Generator exhaust change over
4.4       Main engines
5    The Feedwater and Condensate system
5.1       Surface feed heater
5.2       Contact feed heater
5.3       Boiler Feed Pumps
6    Getting under way
6.1       Low-pressure turbine

1.1 Boiler rooms

Titanic is (or was) a triple screw White Star liner fitted with 5 single-ended and 24 double-ended boilers, operating at 215lb/in2.  These boilers are 5 abreast in 6 boiler rooms, except in No6 Boiler Room (the foremost one) where the fine lines of the ship only allow 4 abreast.
No1 Boiler Room, forward of the reciprocating engineroom houses the single ended boilers used for hotel services and auxiliary supplies in port.  The double-ended boilers are fired for transatlantic passages up to full speed and primarily used for main propulsion.
Stokehold fans provide ventilation for the stokeholds, though for cold starting these cannot be used, as there is insufficient electric supply to run them.  The single-ended boilers may be fired on natural draft on cold-start, with the ventilators turned into the wind.  If sufficient shore supply is available, a stokehold fan may be able to be started, but it is assumed here that the shore supply only provides lighting and small power.  Once under way the vessel operates on induced draft (natural draft) in the same way as a steam locomotive, via large ventilators visible on the upper decks.  (See Figure 1)

1.2 Coal bunkers

Coal bunkers are provided facing the furnaces in each boiler room to enable a ready supply of coal for the trimmers and firemen to stoke the boilers.
Ash chutes are provided to discharge ash from the furnace bottoms overboard at regular intervals to keep the stokehold clear of ash whilst at sea.  In port ash hoists are used to dispose of the ash to shore facilities.
The main steam pipes run the length of the boiler rooms into the reciprocating engineroom for distribution to the engines and auxiliaries.

1.3 Propulsion engines

There are two triple-expansion reciprocating engines situated in the reciprocating engineroom, aft of Boiler Room No1.  Steam from the main steam piping is admitted to the reciprocating engines which, whilst manoeuvring in port, exhaust direct to the vacuum main condenser.  Once Full Away on Passage, large changeover valves redirect the exhaust steam from the reciprocating engines into the low-pressure turbine situated in the turbine engineroom aft of the main engineroom, separated by a watertight bulkhead.
Exhaust steam from the turbine is directed to the vacuum condensers where it is condensed into water (termed condensate) and pumped back into the boilers – see later.  (See Figure 6)

1.4 Electrical power generation

1.4.1 Main generating sets

The vessel is fitted with 4 400kW main generators driven by steam reciprocating prime movers.  Reduced steam at a pressure of 185lb/in2 (12.75 bar) is fed to the engines and exhaust steam is directed - in port or at start up - to the auxiliary condenser.  At sea the generator exhaust steam is directed to the surface feed heater to extract the remaining energy from the exhaust steam and deliver it to the feed heating system.  This configuration gives a total installed power of 1.6MW dc, with three sets covering the full steaming load and one in stand-by. (See Figure 3)

1.4.2 Emergency generating sets

These are termed Emergency/Auxiliary Generating Sets but as they are steam driven, are not able to be cold-started without a steam supply.  There are two of these sets, situated above the waterline on a flat within the engine casing on the Shelter or D Deck, each of 30kWdc output power.  To give a certain amount of redundancy, they are fed by separate steam pipes from three of the boiler rooms (see Figure 1).
With the ship on shore power we will be using these two machines to start up the ship’s lighting systems in order to disconnect the shore power as soon as possible.
This start-up routine assumes the emergency sets as the quickest method of getting off shore power and on to ship’s power, but it could be that the engineers would cut out this stage and just start the main generating sets, though the time taken would probably be a lot longer.

2 Lighting up the boilers

With the lights on shore power so we don’t have to use torches, the firemen are set to work in the required boiler rooms to lay fires in sufficient boilers to provide enough steam for the generators.  Once lit, the boiler draft is adjusted by dampers using natural (induced) draft and the fires start to heat the water in the fire-tube boilers.  Water-tube boilers are much more efficient and faster starting than fire-tube, but hadn’t been invented at this time.  It would take around 7 – 12 hours to warm through and start to raise sufficient steam.  Raising steam too quickly in a cold boiler can lead to thermal stress which is not good for the boiler longevity and could even cause cracking and rupture, especially on riveted boilers.
At the same time, the number of boilers required for sailing are also laid and lit.
The emergency generators are available for starting with a steam pressure of 185lb/in2.
After some hours raising steam we have around 190lb/in2 in the first boilers to be lit.  Most probably boiler rooms 6 and 5 would come on line first as they are the furthest forward, No 6 being open to the main steam lines for warming through, No 5 open to the emergency generator independent line (see Figure 1).  Steam is raised on these boilers with the main stop valves open such that the whole system is taken up to pressure, with all the main steam line drain valves open one to two turns right back to the engineroom bulkhead stops.  This same principle applies to steam systems today. Further boiler stop valves are cracked open once up to pressure. 
Note:

Whilst the single ended boilers in Boiler room No1 were normally used in port, at the time of the sinking these boilers were apparently not lit, so must have been shut down on sailing from the last port (Queenstown).

2.1 Steam line redundancy

For redundancy in main steam lines (Figure 1) - 
The main generators, refrigeration machinery and auxiliary pumps (termed “the auxiliaries”) were fed from a steam main connected to - 
·      Starboard outer pair of boilers in Boiler Room 4

·      Port outer pair of boilers in Boiler Room 2
·      All five single-ended boilers in Boiler Room 1
The main generators were fed exclusively from a steam main connected to - 
·      Port outer pair of boilers in Boiler Room 2
·      All five single-ended boilers in Boiler Room 1 (the line used for electrical power in port)
The emergency generators were connected to - 
·      All five boilers in Boiler Room 5
·      All five boilers in Boiler Room 3
·      All five boilers in Boiler Room 2
·      An auxiliary line from the main steam lines feeding the reciprocating engines in the engineroom

The emergency engines were run regularly to keep the steam lines warmed through in case of emergency.

Note on the sinking:

As the vessel started to plunge by the head, to conserve steam and keep the lights on as long as possible, the main generators would have been fed from the furthest aft steam line, that from Boiler Room 2 above.  As Boiler Room 5 fires were drawn, the steam from the boilers would start to decay, and the isolation from them to the main steam lines and the line to the emergency generators would have been shut off.
As each boiler room flooded and was shut down, the lines from each boiler would be isolated.  The steam reserve in boiler rooms 3 and 2 (Boiler Room 1 was apparently not fired at the time according to the enquiry) would have supplied both the main and emergency generators, and as the latter had a smaller steam consumption it is likely that the main generators would have been shut down and the auxiliaries used to conserve what steam was left in the boiler drums.
Boiler Room 2 was the furthest aft and would have been supplying steam until the end, the auxiliary seawater pump and air pump fed from the port outer pair of boilers, and the emergency generators from all five boilers, though more probably the remaining three in order to separate the auxiliary pumps from the emergency generators.

For an illustration of the steam lines, on the next page is the general layout, Copyright Sam Halpern from the Titanic site - www.titanicology.com where a fuller description of the steam system may be found.

Figure 1 rms TITANIC Steam line redundancy  © Sam Halpern

3 Starting the generators

3.1 Auxiliary seawater pump and condenser

In order to start an emergency generator, the exhaust steam from the engines is directed to the auxiliary condenser.  The seawater passing through this condenser condenses the exhaust steam into water (termed “well condensate”), thereby drawing a vacuum.  Without this the engine would trip on high exhaust backpressure, as the exhaust steam otherwise has nowhere to go.  In addition the condenser is fitted with an auxiliary air pump (or vacuum pump) to increase the vacuum by removing non-condensables such as air, in order to drop the exhaust steam pressure further.
The auxiliary seawater pump is steam driven and situated under the auxiliary condenser on the starboard side of the main engineroom.  (See Figure 6)
With the drains open, steam is admitted to the pump, which circulates seawater through the auxiliary condenser to overboard.  In the same way the auxiliary air pump is started in order to draw a vacuum.  We are now ready to start an emergency generator

3.2 Starting an emergency generator

With all the drains open, steam is admitted to the reciprocating engine, with the exhaust going to the auxiliary condenser.  Once the engine has warmed through and is running at the rated speed of 380rev/min, we go to the main switchboard where the main breaker for the emergency generator is situated.  As the vessel is on shore power, the breaker is closed onto the emergency board.  Even if other generators are on the board, with Direct Current no synchronisation is required, hence generators can be added to the main switchboard at any given time.  On closing the breaker, the voltmeter lamps will light dimly and show a small voltage.  Using the shunt field regulator (also called the exciter), we turn up the voltage until it shows full mains voltage of 100V.
We now have 30kW of power available – 60kW if we start both generators - and can start to get main power on.  The shore power can be disconnected. 
A note on the sinking here – the lights would have stayed on providing an emergency generator was running, which is likely to have been the case as there were no batteries fitted for emergency lighting on Titanic, though Olympic may have been retrofitted after the accident.  Looking at the angle of the waterline at the point where the lights went out – just prior to breaking in two – it is very close to the suction for the auxiliary condenser seawater pump above.   With an emergency generator and the seawater and air pumps running on the volume of steam left in the boilers that remained un-flooded, there would have been little or no reason for any of the engineering staff to remain below, apart from perhaps the Chief Engineer and a couple of volunteers to swing isolation valves, reset breakers etc.  None of the boilers would have been stoked at this point, as the fires would have been drawn and the stokers sent up on deck, and indeed many of the stokers survived the sinking.  One or more of the witnesses stated that most of the engineers – including the Second, Farquharson - were seen on deck prior to the sinking, though none survived.  Once the seawater induction for the auxiliary seawater pump came out of the water, the generator would have immediately stopped on high back-pressure, and the lights would have gone out.

3.3  Starting the main generators

Using the power available from the emergency generator(s) we can now start the stokehold fan for the stokeholds where fires are lit, which will make it easier to get the boilers up to pressure and make it more bearable for the stokers.  As we are consuming steam, we will also be able to start a main feed pump to supply the boilers with feed water as required, described later under the feed system.
The generators are forced lube type, so first we start a LO pump (again steam driven, as are all the engineroom auxiliaries) in the usual way.  Presumably all the exhausts, from any auxiliary pumps that are started prior to getting the main condensers on line, are sent to the auxiliary condenser.
After warming through the steam lines and opening the engine exhaust to the auxiliary condenser, the first and subsequent generators are warmed through and run up to a speed of 325rev/min.  It is not known how many generators would run on the auxiliary condenser, but as the reference work states this was the condition in port, it was likely to be able to run at least two.  Without an electrical single line diagram or load estimate, we have to rely on conjecture.
On the main generator control panel, the breaker is closed for the generator in question and the shunt field regulator adjusted to give mains voltage.  The breaker(s) for the emergency generator(s) may be opened at this stage and the emergency set(s) shut down, though kept warmed through for immediate start on failure of the main sets.  (See Figure 5)
We can now put the other generator(s) on the board as required.  We are up and running and can connect other feeders via the main switchboard distribution (see Figure 4).
As you can see, this is quite a long job compared to a modern diesel powered ship (though steamships still take some time).  A blackout on a modern motorship can be restored within a few minutes, though cold-starting takes longer depending on generator warming through requirements.

4  Starting main engines

We now have power for firing all the boilers necessary for starting the main engines and getting the engineroom ready for sea.
First we have to get the exhaust steam system arranged in a similar way to that of the generators, but in the case of the main engines, the auxiliary condenser is nowhere near big enough to handle the exhaust from a main engine.
For this we need to start to draw a vacuum on the main condensers of which there are two, one either side of the low-pressure turbine in the turbine room.

4.1  Main seawater pumps

As with the auxiliary condenser, we need seawater to condense the steam in order to create a vacuum and drop its pressure to avoid exhaust backpressure on the engines.  These pumps are pretty huge and are driven by compound steam engines.  There are two pumps per condenser (total of four) arranged adjacent to the condensers in the turbine engineroom.  (See Figure 6)
As with all steam engines, these are first warmed through with the drains open, then slowly started up until they are at full revs.  Once the pumps are started, seawater passes through the condensers and discharges overboard – that’s the large discharge that can be seen on any steamship up to the present day.  As a guide, the amount of seawater required to condense the steam is 50 to 80 times the steam flow.  With the reciprocating engines running at 75 revolutions per minute and 24 double-ended boilers on line, a supply rate of just over 260lbs of steam per minute per boiler would be produced, or 260x24x60=374400lbs/hr.  The amount of seawater would therefore be 50 to 80 times this amount, 8,300 to 13,300t/hr – very large pumps.

4.2  Main air pumps (dual system)

The air pumps (called vacuum pumps these days) evacuate air and water from the condensers, with the air pumps extracting non-condensables and helping the vacuum in so doing.  This improves the exhaust flow through the engines and also extracts the maximum energy from the steam. They are situated in the turbine room by the condensers and are of course steam driven.  They are started in the usual way, and left to draw a vacuum on the condensers, usually around 28.5in with an atmospheric pressure of 30in.  In modern day parlance these dual air-water pumps would be termed vacuum pumps and condensate pumps respectively.
In Figure 6 they can be seen inboard of the two condensers in the turbine room. Condensate from the water side of the pumps is returned to the condenser or to the feed tank against the forward bulkhead in order to maintain the condenser level, with air being ejected to atmosphere.  From these tanks the water runs to the hotwell tanks under the hotwell pumps either side in the main engineroom, of which more later.

4.3 Main Generator exhaust change over

Now that the steam and feed system is up and running, we can extract the energy from the main generator engine exhaust by redirecting the steam to the surface shell and tube feed water heater shell, through the tubes of which the feedwater from the hotwell tank passes via the hotwell pumps on its way to the main feed pumps. This imparts heat to the feed water to avoid wasting the energy from the generator exhaust.

4.4  Main engines

By this time the engineers (we assume we are not doing this on our own) will have engaged the steam turning gear on both engines, and are oiling round the main, connecting and crosshead bearings, as well as starting the forced lube oil pumps.  Titanic’s engines are open crankcase, so oil is directed to oil pots when the engine is running by skilled oilers.  The cylinder oilers are also filled and set up to admit cylinder oil in a controlled amount.  After turning the engine, the turning gear is taken out to avoid damage when the engine starts.
Steam is admitted to the engines with the drains full open and the exhausts open via the changeover valves direct to the condensers.  At first the main steam bulkhead stop valves are cracked open until everything is warmed through, whence they can be fully opened.
Once the cylinder drains are emitting steam, we can call the bridge and ask if the propellers are clear for a slow turn ahead and astern.  Once this is given, the reversing gear is set to full ahead and the main steam valve control valve cracked open.  The engine will start to turn ahead at low revs.  After a few turns ahead the control valve is closed and the reversing gear set to astern position.  Again the control valve is cracked open and the engine turned astern for a few revs at low speed.
We are about ready to go, and test the communications between the engineroom, boiler rooms and bridge that we are ready for sea service.  Around the same time an engineer is dispatched to the steering engine room to warm through the steam steering engines and test the rudder from midships to 30 degrees port, back to 30 degrees starboard then returning to midships.

5 The Feedwater and Condensate system

Condensate from the bottom well of the condensers is pumped via the water-side of the dual pumps into the feed tanks on the forward bulkhead of the condenser room.  From there it drains to the hotwell tanks either side in the forward engine room.
 The hotwell pumps draw from this tank and pump the feedwater through two feed heaters, after first sending it through filters to remove oil, grease and other impurities. 

5.1 Surface feed heater

The first is a shell and tube surface feed heater, where the feedwater passes through the tubes.  As mentioned above, the exhaust steam from the main generators at about 5psia passes through the shell of this heater, and imparts its energy to the feedwater, raising it from around 70°F to 140°F, the exhaust condensate from the shell is pumped into the feed downstream of the heater by a mono air pump.

5.2  Contact feed heater

The 2^nd of the two feed heaters is a contact heater where the feedwater comes in contact with exhaust steam from the many engineroom auxiliary pumps and refrigeration units.  It is situated high in the engineroom on D Deck and acts as a deaerator once the air vent at the top of the heater is opened up to the main condenser to extract non-condensable gases (CO2 and O2), which can cause corrosion problems in the boilers.  This exhaust steam input condenses in the feedwater stream – thereby adding it directly into the feedwater - and raises the temperature of the feed water from 140°F to 230°F.  At low load it may be necessary to use live steam into the heater, depending on the energy available from the auxiliaries.  

5.3  Boiler Feed Pumps

From the contact heater the feed water is then extracted under gravity by the main feed pumps and sent to the boilers as required.  Titanic did not have automatically operating feed control valves, so this was a manual operation. The height of the contact heater ensures that there is sufficient positive suction head for the main feed pumps that feed the boilers. In Figure 2 is a schematic of the propulsion steam, feed and condensate system described above, © Sam Halpern.
All is now ready to go, with the stokers bending their backs to raise steam on all the boilers required for leaving port.

Figure 2 rms TITANIC Propulsion steam, feed and condensate system, © Sam Halpern

6  Getting under way

In response to the bridge signals on the engineroom telegraphs, the main engines are manoeuvred accordingly and the ship departs her berth and heads for the open sea.

6.1 Low-pressure turbine

Once the ship is up to 50% power or more ahead, and prior to full away, the low-pressure turbine is warmed through, with its exhaust directed to the two condensers.  At the moment the main engines are exhausting direct to the condenser, so we operate the huge changeover valves (themselves steam engine driven as they are so big – see Figure 6) - to direct the exhaust steam from the engines to the low-pressure turbine, on the shaft of which is the centre propeller.  The turbine will work up to speed, governed by the exhaust steam pressure.
The main engine exhausts are now driving the low-pressure turbine and full power can be worked up once full away is rung on the telegraphs.  This novel method of propulsion is quadruple expansion, with triple expansion through the reciprocating engines, and the final 4^th expansion through the turbine.  It was considered to be an economical method in such a big ship and indeed by the end of her life, the Olympic was performing better than she had when new, with a much lower fuel consumption than the Mauretania (turbine driven) which was a much smaller ship, and only 2knots faster than Olympic; quite a price to pay for an extra 48 miles per day.
We’re done, we’ve been down below on a coal-burner for over 12 hours, and it’s time to go to bed before having to get up again and lose our lives as the ship goes down.

RIP Titanic.

Plates from the publication “Ocean Liners of the Past, Olympic & titanic (1911) 
(With notes to explain the various items of equipment fitted)

Elevation of boiler rooms

Figure 3 rms TITANIC Boiler Rooms 1 & 2

Here you can see the No 1 Boiler Room single-ended boilers with the coal bunker forward, opposite the furnaces. 
Also shown is the main steam pipe that is routed throughout the ship from No6 Boiler Room (foremost) to the engineroom.
On the deck above can be seen the Sirocco fans that are used for ventilation of the stokeholds.  The boilers themselves are fired on “Natural Draft”, with the stokehold pressurised by the fans.  Where the combustion air is ducted via trunking into the boiler furnace, this is termed “Forced Draft”, as employed on Cunard vessels of the era.

Electrical Generating Room

Figure 4 rms TITANIC Electrical Generating Room

This view shows the main generator room with the 4 x 400kW generator sets.  You can see the three propeller shafts passing through this room in the views.
In the profile view you can see the main switchboard gallery above the sets.  Engineers on watch can see from there down to the generators. 

Figure 5 rms TITANIC Sectional View of Main Generator Set

This is a compound reciprocating crosshead type engine driven DC generator of 400kW.  The emergency sets are similar though smaller.

Main switchboard in the electrical shop

Figure 6 rms TITANIC Main Distribution Switchboard

This view of the main switchboard in the assembly shop shows the extent of the electrical distribution around the ship.
At the top are the breakers, under them the voltmeters and ammeters, and below them the large porcelain fuses.

Main Generator Control Panel and Breakers

Figure 7 rms TITANIC Main Generator Breaker Control Panel

Unlike more modern ac and dc switchboards which have the generator breakers integrated with the switchboard, Titanic’s generators had their on control panel and breaker switches.  The shunt field regulators for increasing and decreasing the voltage are on this panel, which is for two of the main generator sets.

Plan of Engine Rooms

Figure 8 rms TITANIC Main and Turbine Engine Rooms

Zoom in to see this picture more clearly.

In the main engineroom can be seen:

1.         The two reciprocating main engines arranged port and starboard, with the steam lines coming through the watertight bulkhead aft of No1 Boiler Room

2.         The auxiliary condenser with the auxiliary seawater circulating pump situated below it

3.       The hotwells and hotwell pumps that transfer the feed water to the feed heaters via the filters, seen against the forward bulkhead port and starboard

4.         The auxiliary air pump that creates a vacuum on the auxiliary condenser

5.       The main feed pumps that draw from the contact feed heater above the engineroom and discharge to the boiler feed lines and thence to the boilers

6.         Auxiliary pumps such as forced lube oil, bilge, ballast, fire and general service

7.         Refrigeration machinery on the port side outboard

In the turbine room can be seen:

1.         The low pressure turbine driving the centre propulsion shaft and propeller

2.       The huge changeover valves to divert exhaust steam from the main engines to either the condensers direct, or via the low-pressure turbine.  The arms shown on top of the valves are part of the steam driven machinery that operates them as they cannot be shifted manually

3.         The main condensers either side of the turbine

4.         The main seawater circulating pumps outboard on both sides

5.         Condenser feedwater tanks

6.         Dual water-air pumps (condensate and vacuum pumps)

Written by Stephen Carey

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