Re-awakening a 'cold' ship

Champagne Murphy

Champagne Murphy

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A short while ago there was a thread about cruise ships anchored off the South coast with just generators running. The Admirable Admiral pointed out that this was damaging to the environment. Ah, says I, (cleverley) the ship can't be started like a car. 'Why not! she says and of course I don't know.
So what is needed to start from cold?
And for clarity, I've no wish to pinch a ship, I'm just interested.
 
I have started up a 'dead ship'. Emergency generator (hand started) on, emergency air compressor on to charge the starting air tank, start main generators, fire up the Cochrane boiler to heat the fuel etc,warm through the main engine, turn the engine using the turning gear, start the separators, cylinder lubrication on, check all systems. Get permission from the bridge. Start her up for a test.

Electricity is the vital thing. Until that's on you can't do anything. Not even make a cup of tea!
 
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A friend's son is a deck officer on a cruise ship. The deck crew and engineers are still working and moving the ship around regularly with no passengers. I don't know the details but I understand that it's cheaper to do this than to mothball the ship and start it up again from cold.
 
Blimey Poignard...how long did it take to "wake up", I guess it would be a problem if your anchor was dragging!

I've bee following the Cruise ships off Weymouth on AIS. They seem to be anchored then go for a pootle about then re-anchor. Their tender's also seem to go walkabout, one going south into at least the middle of the channel! I guess they are bored
 
Black start from warm can be as fast as 30 seconds on modern drill ships, a test that I have witnessed frequently. However, there is a big difference between cold start and warm start and also the level of stacking, or preservation that the ship has been put into. For a drill ship with all the drilling equipment in cold stack, fully preserved, about 3 months total to remove preservation products, reconnect, commissioning A and B from preservation (connection, then function testing). The marine package from cold is usually just a week to get engines out of preservation and fully running with all life support in place.
 
matt1 said:
Blimey Poignard...how long did it take to "wake up", I guess it would be a problem if your anchor was dragging!

I've bee following the Cruise ships off Weymouth on AIS. They seem to be anchored then go for a pootle about then re-anchor. Their tender's also seem to go walkabout, one going south into at least the middle of the channel! I guess they are bored
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I was talking of a ship that had been laid up awaiting a new owner. She had no crew on board until we, her new crew arrived. None of us knew the ship, the Chief Engineer was young and inexperienced on his first trip as Chief, I was 3rd Engineer/Electrician, the 2nd Engineer was a good man at his job. We took over in Zeebrugge or maybe it was Anteerp. Next day we sailed to Felixstowe and loaded general cargo for Barbados, from there to Curaçao, then back to Europe.
 
I watched a YouTube video about starting a big ship's engine. As far as I remember, it took about an hour if the systems were already awake. The title was probably something snappy, like 'starting a ship's engine'.
 
A cruise liner has a vast number of ”hotel” systems to bring back in a cold start. Water, heating, sanitation, air conditioning, galleys - the list is long and complex. Each of those systems will require recommissioning once the generators and main engines have been restarted. Some systems will fail as they’re restarted, leading to a need to repair/replace them whereas if they’d been left running they probably wouldn’t have given a problem.
I base this on the experience of getting vehicles back on the road after they’d been mothballed for an operational tour: as we entered training, we spent a month or so putting the fleet into light care and preservation. A year later, on our return from leave, we then spent 2 months getting them back on the road: a good 50% required significant attention from the workshops as one system or another had failed.
To me it makes sense that the liners are kept with a crew on board, systems still operational and that they’re taken off every now and then for a “trip round the bay”.
 
I was talking to the chief electrical designer of a small diesel-electric ship the other day - the sort of vessel where the heart of the propulsion system isn‘t an engine but a 750v DC bus. Individual generators are started and stopped willy-nilly, but the main bus has to be kept live at all times or it’s a real pain to restart.

Partly because everything is electronically controlled, and with the bus down only a few backup control systems are running off the emergency 24v batteries. And partly because you can’t just throw a switch and apply 750v all in one go, the inrush current would be far too high, so the bus has to be “pre-charged” to nearer the working voltage so that the current can be limited by a reasonable-sized resistor pack.

Those are the parts I followed, at least. I got the impression there were other issues as well; in general he seemed mildly horrified at the notion of “just turn it all off”.

Pete
 
As a Chief Engineer when I was a bit younger on cruise ships when we anchored the generators are always kept running and they are cooled via the main engines .i.e the Mains are kept warm .We would normally be on 30 mins notice and we could be ready to heave anchor in that time .
The odd times we totally blacked out we could have the ship powered up and running again in about 30 mins because every thing was warm .
On occasions when we were leaving dry dock after the ship was totally dead it was a case of start emergency generator run compressor and fill air receivers . Then start generators warm through mains slowly and then your ready to go ,would take between 8 and 12 hours depending on where you were and the sea temperatures . In emergency this procedures could be carried out a lot quicker but I’d not do the engines any good .
Our engines were slow speed diesels with a bore of 760 mm and stroke of 1500 mm . Max rpm 120
Most modern ships have medium speed diesels smaller and run faster .
On steam ships such as Canberra it was a lot longer to get started as you had to warm the boilers slowly get up to pressure and warm turbines through before going any where .
 
Koeketiene said:
Grey funnel line it used to take several months to take a ship out of mothballs.
Don't see why it should be different for cruise ships.
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I have served on both warships and merchant vessels (including a cruise liner) and a warship is much more complex by virtue of its weapon systems. But even so, I'm sure HM Dockyards could get a ship ready for sea, and war, very quickly if they had to; as they did for the Falklands campaign.
 
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