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The contents of this post were lost in the events of yesterday, so there is unfortunately nothing to fill the space above.  (BTW, few points about it all: thanks to all those who have emailed through, or commented on the Forums, or on Twitter, or just thought the situation sucked and didn’t comment – all are appreciated.  I deliberately turned off comments on the previous post if you tried and couldn’t find a way of posting a comment.)

This channel will resume its normal transmission shortly.

Actually, in writing the first line it bought back a few things, and seeing as there is no real content here, might as well mention stuff off-topic.

In technical manuals etc, where there is a blank page (such as at the end of a chapter, or the facing page of a new chapter, back of a illustration etc), they don’t just leave a blank page, they actually put the term “This page is intentionally blank”.  It saves confusion, and concern.  If you are reading the instructions for a complicated, expensive machine and come across a blank page, you don’t want to be left wondering if it is deliberately blank, or a misprinting in which case some vital instruction has been lost.

Guess the engineers on ANZAC had wondered if that was the case one day early in its service.

There is a regular exercise on a Naval ship of conducting ECCDs – Emergency Casualty Control Drills.  In essence, the way to train for dealing with an engineering emergency is to actually create that emergency for real, and see how the crew react.  This is done in a supervised way of course (as in turning off a system that creates a situation, but in a known way for the monitoring staff).  On a steam ship, it could be done by turning off supply water, resulting in a low-water condition in a boiler, which is a genuine emergency (imagine the kettle running dry, when the kettle is 2 stories high!), and seeing how long it takes for the situation to be discovered, isolated, and recified.

One day early on, on HMAS ANZAC, a senior engineer (no, not me – I was in a different Navy (NZ rather than Oz!)) was going through the new manual (ANZAC being the first-of-class), and found a section on the CPP (continuous pitch propeller) that talked about a certain valve, with the instruction “do not turn off this valve while the ship is underway, as it may result in unexpected results” (or words to that effect).  On a Gas Turbine powered ship, it would take a significantly complicated gearbox to put in a reverse gear, so instead the blades of the propeller can be twisted so the propeller itself can either thrust to the front, or to the rear depending on the angle of pitch chosen (and how much).  (Helicopters have a similar concept for example).  The CPP control box then is rather important, as loosing control over the pitch of the propeller could result in the ship slowing, or turning (you can slowly turn a ship simply by slowing, stopping or reversing one of the two propellers), or going backwards.

ANZAC Class Propeller in Drydock

So a valve that you shut that’d cause “unexpected results” sounded like a perfect ECCD.  I guess after the fact, the engineer would have liked to have found a page that had some additional information, rather than “This page is intentionally blank”.  The shaft of a frigate is about 1m (3′) diameter, if not a bit bigger.  It transmits around 15,000 HP to the propeller.  Around the outside of the shaft in a small, tight compartment is the CPP control box, under which is the valve in question.  So a box (all steel), surrounding a massive shaft, transmitting significant amounts of power from the engine to the propeller.

Aft Generator Room & CPP Control

The valve was shut, stopping a recirculating oil and yes, the results were unexpected.  But not what you’d kind of hope.  The CPP control box actually needed that recirc oil a lot more than the manual let on.  Instead of some interesting ECCD exercise, the control box instead attempted to weld itself to the shaft, and in doing so found it was happier holding onto the shaft than being bolted to the deck.  I can’t imagine what it was like down there next to the shaft after that – turning at 100 RPM or so, whirling with an eccentric weight attached, and the sound of the box ripping itself loose of the deck.  As you can see, there is not very many places to go, and you can hardly even stand upright from memory.  Needless to say, the manual was updated (and said valve padlocked)

Anyway, getting off track during an off track article.  The point is, sometimes a manual will have a page that is deliberately blank.

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