Rare Engineroom Snipe Posted March 28 #526 Share Posted March 28 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. Link to comment Share on other sites More sharing options...
Rare Engineroom Snipe Posted March 28 #527 Share Posted March 28 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. Link to comment Share on other sites More sharing options...
PC 462 Posted March 28 #528 Share Posted March 28 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. 1 Link to comment Share on other sites More sharing options...
mo&fran Posted March 28 #529 Share Posted March 28 @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. 2 1 Link to comment Share on other sites More sharing options...
CruiseBride926 Posted March 28 #530 Share Posted March 28 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. Link to comment Share on other sites More sharing options...
mo&fran Posted March 28 #531 Share Posted March 28 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. Link to comment Share on other sites More sharing options...
emeraldcity Posted March 29 #532 Share Posted March 29 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? Link to comment Share on other sites More sharing options...
Sunshine3601 Posted March 29 #533 Share Posted March 29 (edited) 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 2 Link to comment Share on other sites More sharing options...
BND Posted March 29 #534 Share Posted March 29 (edited) 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 2 Link to comment Share on other sites More sharing options...
Starry Eyes Posted March 29 #535 Share Posted March 29 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. 1 Link to comment Share on other sites More sharing options...
BillB48 Posted March 29 #536 Share Posted March 29 (edited) 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 Link to comment Share on other sites More sharing options...
Sunshine3601 Posted March 29 #537 Share Posted March 29 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 Link to comment Share on other sites More sharing options...
BillB48 Posted March 29 #538 Share Posted March 29 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. 1 Link to comment Share on other sites More sharing options...
Rare Engineroom Snipe Posted March 29 #539 Share Posted March 29 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. Link to comment Share on other sites More sharing options...
Rare TPKeller Posted March 29 #540 Share Posted March 29 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 3 Link to comment Share on other sites More sharing options...
HBE4 Posted March 29 #541 Share Posted March 29 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. 3 Link to comment Share on other sites More sharing options...
chengkp75 Posted March 29 #542 Share Posted March 29 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. Link to comment Share on other sites More sharing options...
Ocean Boy Posted March 29 #543 Share Posted March 29 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. 2 Link to comment Share on other sites More sharing options...
chengkp75 Posted March 29 #544 Share Posted March 29 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. 1 Link to comment Share on other sites More sharing options...
mo&fran Posted March 29 #545 Share Posted March 29 Baltimore port webcam is streaming live on Youtube. I see 2 tugs with barges, one with a crane. 2 Link to comment Share on other sites More sharing options...
Rare TPKeller Posted March 29 #546 Share Posted March 29 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 Link to comment Share on other sites More sharing options...
BND Posted March 29 #547 Share Posted March 29 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. Link to comment Share on other sites More sharing options...
chengkp75 Posted March 29 #548 Share Posted March 29 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. 1 Link to comment Share on other sites More sharing options...
chengkp75 Posted March 29 #549 Share Posted March 29 Camera is now pointed towards Sparrows Point, and there are two crane barges there. 1 Link to comment Share on other sites More sharing options...
Rare TPKeller Posted March 29 #550 Share Posted March 29 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 Link to comment Share on other sites More sharing options...
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