Container Ship Struck Key Bridge in Baltimore, Bridge has Collapsed

[Engineroom Snipe]

7 minutes ago, mo&fran said:

Doesn't that energy come from the generator? does that mean if you want to stop, the engine turns off, or is there a clutch between the engine and propellor shaft.

The turbocharger energy comes from exhaust gas pulses from combustion.

[Engineroom Snipe]

1 minute ago, Engineroom Snipe said:

The turbocharger energy comes from exhaust gas pulses from combustion.

As @chengkp75 stated, it is a lagging power boost which needs increased power pulses from the engines to get it up to speed.

[PC 462]

4 hours ago, chengkp75 said:

Just remember that until the last few moments, the ship was in the shipping channel.  Also, like most cruisers, and one poster on this thread, I believe, perspective is deceiving, as it looks like the ships are almost touching the bridges as they go under, so how well a person could determine that a ship was too close to the bridge abutment is up in the air.

This is true.  I have been driving over the Key Bridge when a vessel was passing underneath and would never have been able to see it being off course, unless it was way, way, way off course.  Also, the workers were on the side of the bridge away from the approaching vessel, so there would have been no way for them to see it coming.  A ship passing under the bridge may have seemed routine to them, and no special cause for concern, or even interest.

 

 

[mo&fran]

@chengkp75

Let me give you a little background about myself .  My degree is mechanical engineer.   I worked 42 years at Pratt & Whitney as a performance engineer designing engine cycles for supersonic applications, both commercial (NASA contract) and military.  I retire in 2008 at 65, but worked at outsourcing for another 6 years.  Even at 80 years old, I continue to be curious how things work.

[CruiseBride926]

2 hours ago, smokeybandit said:

Are they cutting your cruise short a day because of it?

I haven’t heard anything about that as of now but we’ll see. 

[mo&fran]

24 minutes ago, chengkp75 said:

When the propeller stops, the engine stops. When the propeller goes astern, the engine rotates in the other direction.  The engine is directly bolted to the propeller shaft.

 

Not sure what energy you are talking about.  Energy to drive the turbocharger comes from the main engine's exhaust gas spinning a turbine which is shafted to a compressor, which compresses the combustion air for the main engine.  So, when it starts, there is no energy from the exhaust (there isn't any exhaust), so the "auxiliary blowers" switch on and compress some air for the engine.  As the exhaust gas builds up in volume and temperature, the blowers switch off, and the turbo spins on its own, driven by the exhaust.

Oh, so it can rotate in either direction. Turbo chargers are not parasitic obviously , they get energy that would have been wasted, at by compressing inlet air improves power and efficiency (Cycle efficiency increases with higher pressure ).  With a turbocharger the powerplant becomes a combined cycle powerplant.

[emeraldcity]

So now that it's determined where the current passengers will disembark, how does the cruise line deal with the obvious PVSA violation. Do they file for an exemption?

 

[Sunshine3601]

7 minutes ago, emeraldcity said:

So now that it's determined where the current passengers will disembark, how does the cruise line deal with the obvious PVSA violation. Do they file for an exemption?

 

I highly doubt any violation will be imposed due to the situation  

Edited March 29 by Sunshine3601

[BND]

7 minutes ago, emeraldcity said:

So now that it's determined where the current passengers will disembark, how does the cruise line deal with the obvious PVSA violation. Do they file for an exemption?

 

This is an emergency situation.  

Edited March 29 by BND

[Starry Eyes]

7 minutes ago, emeraldcity said:

So now that it's determined where the current passengers will disembark, how does the cruise line deal with the obvious PVSA violation. Do they file for an exemption?

 

As the port of Baltimore is so clearly unavailable, the cruiseline should not have any difficulty obtaining a waiver.  

[BillB48]

5 minutes ago, Sunshine3601 said:

What violation if they dock at Norfolk instead of Baltimore?   

They have transported passengers from one US port to another US port without having visited a distant foreign port.  The powers that be can waive that in cases such as this.

Edited March 29 by BillB48

[Sunshine3601]

Just now, BillB48 said:

They have transported passengers from one US port to another US port without having visited an foreign port.  The powers that be can waive that in cases such as this.

I edited my post right after I submitted....had a brain fart😁

Plus the current cruise has stopped at several foreign ports before their return to a US port

[BillB48]

Just now, Sunshine3601 said:

I edited my post right after I submitted....had a brain fart😁

Plus the current cruise has stopped at several foreign ports before their return to a US port

I left out distant, which is what makes a cruise eligible to transport passengers between two US ports.  The post has been editied.

 

[Engineroom Snipe]

1 hour ago, mo&fran said:

Oh, so it can rotate in either direction. Turbo chargers are not parasitic obviously , they get energy that would have been wasted, at by compressing inlet air improves power and efficiency (Cycle efficiency increases with higher pressure ).  With a turbocharger the powerplant becomes a combined cycle powerplant.

 

I respect your background.

 

A 2 cycle diesel uses a forced air blower (in many cases called a 'root' blower) which compresses atmospheric air to a higher pressure. The air is hot and dense after compression. A water cooled heat exchange often called an "after cooler" is used to cool the compressed air to make it more dense. After that, the turbocharger uses wasted energy of the exhaust combustion cycles to once again compress the intake air before injection into the engine.

 

A lowly standard engine that would normally provide 198 hp without after cooling or turbocharging becomes a 460 hp powerhouse.

 

As you know from your experience, the trade-off is engine life span before destruction.

 

More hp equals more heat and the metal block does not have as many engine hours available.

[TPKeller]

5 hours ago, toad455 said:

 

I also don't ever remember Norfolk having more than one ship sailing from there. It's always been a limited summer home port for Carnival. Has Royal ever sailed from there?

 

I sailed from Norfolk on Empress in 2007 and Grandeur in 2009.  Two of my favorite cruises.

While we're talking about Royal Caribbean and Norfolk, a couple years ago I worked up this to-scale mock-up image of what an Oasis class ship would look like docked at the Norfolk Cruise Terminal.  Wouldn't that be a hoot!?  😄

 

Theron

[HBE4]

58 minutes ago, TPKeller said:

 

I sailed from Norfolk on Empress in 2007 and Grandeur in 2009.  Two of my favorite cruises.

While we're talking about Royal Caribbean and Norfolk, a couple years ago I worked up this to-scale mock-up image of what an Oasis class ship would look like docked at the Norfolk Cruise Terminal.  Wouldn't that be a hoot!?  😄

 

Theron

 

Amazing how skinny & small the battleship Wisconsin looks compared to Oasis.  

 

[chengkp75]

9 hours ago, mo&fran said:

With a turbocharger the powerplant becomes a combined cycle powerplant.

Every marine diesel engine is turbocharged, whether 2 stroke or 4 stroke, direct coupled slow speed, or medium speed generator.  Some engines will also use exhaust gas heat to boil water in an "exhaust gas boiler", and this steam then drives a turbo-generator, which can generate electricity equal to about 10% of the rated output of the engine.  Waste heat from the cooling water system is also used to boil sea water in flash evaporators to produce fresh water, as well as heating domestic hot water.  This type of plant provides the highest thermal efficiency of any power plant.

[Ocean Boy]

6 hours ago, HBE4 said:

 

Amazing how skinny & small the battleship Wisconsin looks compared to Oasis.  

 

Yeah, those Iowa class battleships actually look like ships. 

[chengkp75]

8 hours ago, Engineroom Snipe said:

More hp equals more heat and the metal block does not have as many engine hours available.

This is why marine diesel engines are built with separate, replaceable cylinder liners, not uni-block construction.  Slow speed engines typically have piston overhaul periods of about 12,000 running hours, but liners last around 48,000 hours.  Medium speed engines, also with separate liners, tend to be completely overhauled every 12,000 hours.  The largest slow speed diesel engine produces 80Mw of power, or 70% more energy than Oasis of the Seas 6 engines combined.  The engine weighs 2300 tons, is 44 feet tall, and 90 feet long.  Each piston is 37" in diameter.  The engine produces 107,000 horsepower using 3/4 of a gallon of fuel per revolution, and when turning at top speed (102 rpm), that is 72 gallons/minute.

[mo&fran]

Baltimore port webcam is streaming live  on Youtube. I see 2 tugs with barges, one with a crane.

[TPKeller]

51 minutes ago, mo&fran said:

Baltimore port webcam is streaming live  on Youtube. I see 2 tugs with barges, one with a crane.

 

Link?

 

I can only find one live streaming webcam, which is showing the bridge site from down-river looking back towards the port, but I see no barges or cranes.  Marinetraffic also shows nothing new this morning.

Theron

[BND]

9 hours ago, HBE4 said:

 

Amazing how skinny & small the battleship Wisconsin looks compared to Oasis.  

 

Most Naval vessels are much narrower (width to length ratio) than cruise ships. 

[chengkp75]

8 minutes ago, TPKeller said:

 

Link?

 

I can only find one live streaming webcam, which is showing the bridge site from down-river looking back towards the port, but I see no barges or cranes.  Marinetraffic also shows nothing new this morning.

Theron

Every now and again, the camera pans around, I think I saw some barges an hour or so ago.  Non-self propelled barges don't always have an AIS, so they won't show up on tracking sites.

[chengkp75]

Camera is now pointed towards Sparrows Point, and there are two crane barges there.

[TPKeller]

12 minutes ago, chengkp75 said:

Camera is now pointed towards Sparrows Point, and there are two crane barges there.

 

Either I missed it again or I'm looking at the wrong camera!  😕

I'll keep an eye on it, thanks!

 

Theron