Friday, 8 May 2015

HMCS PRESERVER: Engine Room Tour (Updated with corrections)

At the time of writing this, only two steam-driven ships remain in the Royal Canadian Navy: HMC Ships PROTECTEUR and PRESERVER. Indeed, these Auxiliary Oiler Replenishment (AOR) vessels were the last two RCN ships designed and built with steam power, and shortly after they were commissioned the RCN introduced new surface warships with all gas turbine propulsion (IROQUOIS class), and later a combination of diesel and gas turbine propulsion (HALIFAX class). Similar ships to PROTECTEUR and PRESERVER built today are most likely diesel powered.

Being the last steam-powered vessel remaining in RCN service in Halifax, and soon to pay off and be discarded, I was keen on photographing PRESERVER's engine and boiler rooms for posterity. While I have done something similar for the Y100 steam plant in the ST. LAURENT and subsequent destroyers, the ships I toured had been out of service for several years, and my camera gear was somewhat deficient. This time around, the commentary won't be as good, but at least the photos will be better. 

Entering PRESERVER's engine room from the Machinery Control Room (MCR) (which itself will be covered in a later post), I was greeted by one of the largest open spaces onboard ship (second only, I think, to the helicopter hangar):

Engine room looking forward and to starboard from #2 Deck level.
The two grey items in the centre of the photo above are the low pressure (LP) and high pressure (HP) turbines, respectively. The astern turbine is mounted within the LP turbine casing, and on the same shaft. The grey shape to the bottom right (both forward and aft of the catwalk) is the double reduction gearbox. Immediately port of the LP turbine on #3 Deck (main level) are the two evaporators that make fresh water for the boilers (of which I have video, but no still photography for some reason). Aft of the gearbox are the two 1000 kW turbo alternators (steam driven generators). 

Another view from Deck #2, from further to starboard. The HP turbine is top left.
Another view from Deck #2, from further to starboard. The LP turbine to the right. The evaporators are behind the piping in the centre of the image.
A view looking directly down on top of the gearbox, giving a better idea of its size.
In the photo above, you can see the two shafts coming out of the two turbines, and connecting to the gearbox. A single shaft exits the gearbox along the ship's centreline, below the platform at the bottom of this photo, which connected directly to the propeller shaft. The reduction gearbox is required to transfer power from the high speed turbines to the propeller. Steam turbines are at their most efficient at relatively high revolutions per minute (RPM), while a ship's propeller is most efficient a much lower RPM. In this case, the gearbox also combines the power from the two turbines, and transmits it to a single propeller shaft.

After taking these photos, I descended the ladder to the left of the image to Deck #3, which is the main level of the engine room.

The Joy pump  compressor supplies control air. I don't remember what it does, apart from make noise.  
Port turbo alternator, looking aft and starboard.
Under normal conditions, electrical power is provided via the two 1000 kW turbo alternators, which are located port and starboard at the aft end of the engine room. These turbo alternators are self contained (they have their own condensers), although they receive steam from the main boilers. 

Port turbo alternator, looking aft and to port.
It was one of these turbo alternators in PROTECTEUR that caught fire while she was sailing off Hawaii in 2014, leading to her (slightly) early retirement. A lube oil line burst, sending a mist of 150 psi oil up into 500+ degree steam piping causing it to ignite. The fireball went forward in the engine room, hampering fire fighting efforts and attempts to shut off the oil supply. It was a very unfortunate event, and the crew did well to save the ship with no loss of life.

At times when steam is not available, auxiliary power is provided by a diesel generator, and a Solar gas turbine generator up forward on main deck level. This auxiliary power is necessary to start the boilers, and bring up enough steam to start the turbo alternators and main engine when bringing the steam plant online, after which the diesel and gas turbine generators can be shut down (and kept in reserve for emergencies). 

Errr....a dooflicky. Don't remember what this is Located immediately starboard of the HP turbine are the main engine air ejectors, which "...remove air and non-condensable gases from the main condenser to create and maintain main engine vacuum". The tank to the right, with the John Deere logo, is a deaerator. Get it? Deere? Oh, dear.
Looking forward over the tops of the two steam turbines.
You can get an idea, from the photo above, of the rat's nest of steam pipes connecting the boilers to the propulsion turbines and the turbo alternators, the turbines to the condensers, and back to the boilers. As in any aging powerplant, the piping can get old and brittle, and sometimes leaks or breaks. The difference with a steam plant is that not only do you have to worry about fuel and lube oil lines breaking, but you also have to worry about the steam lines. It was explained to me that a corn broom could be used to identify steam leaks - it is waved in the air around a steam line, and if there is a steam leak, the escaping high pressure steam (at up to 865 degrees at 600 psi) will cut the corn off the broom like a knife. It doesn't bear thinking about what that would do to human flesh.

The HP turbine looking forward and to port. The springs on top of the HP turbine are part of the auxiliary throttles.
The steam turbines are normally controlled from the MCR, however, local controls are provided for the turbines in case control from the MCR is lost. The auxiliary throttle station is located at the forward end of the HP turbine.

Auxiliary throttle station looking to starboard. The telegraph repeater is the circle to the left of the clock, below what appears to be a SHINCOM panel.
The auxiliary throttle station provided manual control to both steam turbines, as well as the astern turbine. The local telegraph reports throttle settings ordered from the bridge, independent of the telegraph in the MCR - presumably throttle settings could also be transmitted by other shipboard communications, including SHINCOM, in the event the telegraph was inoperative. There are two red pipe handles, one of which can be seen to the left of the image, which are used to control the auxiliary throttles. 

Auxiliary throttle, with one of the pipe handles installed. The grey rod attached to the base of the throttle handle, below the red rod, is normally hanging down, but is flipped up to attach to the throttle itself in this photo.
The operator at this station would operate the red handle to provide the required revolutions ordered from the bridge.

Looking down on the gearbox at the aft end of the HP turbine, to starboard and aft.

The double reduction gearbox, looking forward and to port.

The gearbox, looking forward and to starboard. The platform bridges the propeller shaft.
Immediately behind the catwalk over the shaft is the thrust block, which transmits the propeller's thrust to the hull and presumably prevents that thrust from affecting the shock mountings of the gearbox and turbines. 
It was at this point during the tour that a classic (in my mind, anyway) miscommunication occurred. Knowing that the old steam DDEs had a way of stopping the shaft from turning when the ship was being towed at low speeds, to prevent the turbines from being turned backwards (or when the auxiliary inflatable stern seal is in place, see below), I asked if they had a "brake". Misunderstanding me, my ever helpful guide replied that "Yeah, at 10:00, we have soup if you want." Apparently, it is actually known as a "lock", and is placed on the shaft when needed.

(As an aside, I did get soup in the wardroom during a "break" in my tour. It was french onion, and it was delicious.)

Looking forward along the propeller shaft, with the gearbox in the background. The plummer block is the grey object around the shaft.
Looking aft along the propeller shaft.
Having a deep displacement hull, and only a single shaft, the propeller shaft leaves the gearbox and travels maybe 30 feet to the stern seal, which can be seen in the background of the photo above, where the shaft passes through the bulkhead. In that 30 feet, the shaft leaves the gearbox, passes through the thrust block, a plummer block (which supports the weight of the shaft), and then the stern seal or stuffing box. In the case of the stern seal leaking, there is an inflatable auxiliary seal that can be installed, but only if the shaft is stopped and not turning.

With PROTECTEUR laid up after her fire, and PRESERVER similarly laid up due to hull corrosion issues, the RCN will likely never have another steam plant in operation - these were the last two. And this is largely a good thing, as modern gas turbines and diesel engines are more compact, lighter, have higher power to weight ratios, require less manpower to operate, and are generally less hazardous to the crew. That said, there will be former and serving Navy sailors (and my guides were good examples of the latter) who will miss these powerplants now that their page in the RCN history books has been turned.

(Updated on 21 May with corrections to some equipment descriptions, based on comments to my Facebook post.)

2 comments:

  1. Thanks for this. I lived directly above this for almost 2 years but never "visited."

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  2. Thanks for taking the time to share this era of ship propulsion. I sailed on the HMCS Protecteur as a stoker in the early 80's, and you just gave me a very cool trip down memory lane!

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