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On 27/09/2013 7:06 PM, Sir Gregory Hall, Esq· wrote:
"injipoint" wrote in message ... On 26/09/2013 7:05 PM, wrote: On Thu, 26 Sep 2013 08:56:31 +0300, injipoint wrote this crap: Back when I was in white and gold, I watched, with a group of others, a US CGN leave our little port (military) He had to join up with a commercial dredged channel, not very wide. He wandered slowly to the ENE to link up and turned. The area is occasionally prone to Anti-Nuke nutsos and he didn't want to get hampered in the channel. He was headed now WNW. If you have a reactor as a power plant, you use it. So he put the pedal to the metal and let it rip. Not a wake, a rooster tail fully 50' high off the stern. We could see it from 2 miles away. They do move some water when they go by. Just curious, how did it take the nuke to go from slow to go? However, he could have powering up the reactor as he was leaving the channel and then just powered up the engines when he got clear sailing. At nuclear electrical power plants it takes days to get to full power. Don't drink and drive. Unless you have a good cup holder. --- news://freenews.netfront.net/ - complaints: --- Been powering up the reactors for a day probably. They'd never say. Just switched the power to the engines when he turned. The N-subs do the same thing, but no rooster tail. They just go hell for leather so any dickhead on a surfboard or in a canoe etc who wants to "stop" one for a photo-shoot has to deal with something that's already doing 20knots "Sorry, couldn't stop in time" It's my understanding that nuclear subs are powered by steam turbines which generate electricity for the electric motors that run the propellers. The steam for the turbines comes from the heat of the fission reactor. Lower a few more fuel rods and it doesn't take but a few minutes for the core to heat up and the cooling water temperature rises along with it. Not sure but I think it might take longer. I know they take time to lower the power, like a day or about that but I don't know enough about the process to know the start up bit. |
#3
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posted to rec.boats.cruising,alt.sailing.asa,rec.boats
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On Fri, 27 Sep 2013 21:06:13 +0300, injipoint
wrote: It's my understanding that nuclear subs are powered by steam turbines which generate electricity for the electric motors that run the propellers. The steam for the turbines comes from the heat of the fission reactor. Lower a few more fuel rods and it doesn't take but a few minutes for the core to heat up and the cooling water temperature rises along with it. Not sure but I think it might take longer. I know they take time to lower the power, like a day or about that but I don't know enough about the process to know the start up bit. I was a USN boilerman on a DDG. Some years ago, but here's how it worked than. Nuke or oil-fired is the means to generate steam in boilers. Whether nuke or oil, steam is steam. Boilers is where it all starts. Steam powers turbines. For main propulsion, generators, and auxiliaries like pumps and forced draft blowers feeding the boilers. Steam also powers evaporators to produce fresh water. Lighting off a cold boiler is the only lengthy process. Took about 2-3 hours on my ship, but since boilers were only "cold iron" in a safe port like Norfolk, Va, they are normally hot and ready and powering the ship even in port. Not much steam demand when not propelling the ship, so they are basically idling. When cold iron in a "safe" port, electric cables and fresh water lines are hooked up to the ship. You need electricity to go from cold iron to a hot boiler. We could probably go from cold iron to "full hot" in less than an hour, but it's better to bring up heat/pressure slowly to avoid heat and expansion shock, so we always took a measured pace, firing only one of the boiler 5 burners. Nowadays steam is dead - except for nukes. As far as I know non-nukes are now all gas turbine, diesel, turbo-diesel, etc. Here's how it works with a steam-powered ships like injipoint observed. I'll use my DDG as an example, but there won't be much variance. Just replace rod movement for "burners." In port a forward and aft boiler are hot and running on one burner each. Each fireroom has 2 boilers, but normally only one is hot. Running all boilers at full power gains very little extra speed. Boilers have scheduled maintenance even underway, and often the idle boiler is open and not operational for this reason. The forward fireroom feeds steam to the forward engineroom main turbines. That runs the starboard shaft. Aft runs aft and port shaft. Even on my ship built in 1961 most boiler controls were automatic. Feed water, oil pressure, etc. The main "humans" operating the boilers were the burner man and the console operator. Operating pressure was 1275 psi. Others on various fireroom watch stations monitored temps and pressures, and were ready to take action for "casualties." When steam demand began dropping pressure, the burnerman manually pushed in another burner, and lit it by pulling down the oil control valve. Oil on a burner was either shut or wide open. The console operator had little to do except adjust oil pressure when demand was low, and adjust "excess" air, to avoid stack smoke. But the console also provided an overview of many systems. So you leave port on maybe 2 of the 5 burners, with low oil pressure. Say you're doing 4 knots. The skipper wants to avoid a bottom structure by backing one screw. Not sure about how the ship is actually controlled, but I've seen this many times. He sends a telegraph command to the engineroom powering that shaft. Can't remember if that comes to the fireroom simultaneously, or the engineroom repeats it. Full astern. The engineroom cranks opens their main throttle, and starts pulling steam. In the fireroom a full astern bell means the burnerman pushes in and light all burners as fast as he can, because all hell will break loose. As steam pressure drops, everything winds up to maintain pressure, It's like banshees screaming. Forced draft blowers, feed pumps, oil pumps, air flow, burners burning, steam flowing. There are limits. The engineroom throttleman isn't supposed to take pressure below 1120 psi. That's the prescribed pressure for boiler shutdown. At sea there's no electricity except that provided by steam. You need the steam to run the pumps to restart the boilers. I've seen it get close, and a couple times warned the throttlemen I was going to shut it down. They listened. My ship was designed for ASW, so we spent a lot of time chasing Soviet subs. We were armed with nuke ASROC missiles. Top speed was 27 knots. We were 4500 tons. But she was geared for ASW, so she would squat and gain speed pretty quickly when you opened the throttles. No roostertail, but a pretty massive stern hump. http://www.navsource.org/archives/05/01003.htm That says top speed 33 knots. Maybe with 4 boilers and overload burner tips. Never did that when I was aboard for 3 1/2 years. 1964-67. Flank speed was 27 knots. We would usually measure speed by screw shaft "turns," not knots. I never heard more than 27 knots mentioned, and can't remember the turns, maybe 40-50 max. Going from 1/3 ahead to full to flank is the usual speed progression of ships. If not done abruptly, there's no real excitement. From dead to flank is a lot of action and noise. From flank to full astern or vice versa is hectic, but only done in open sea during "exercises." It's been a long time, but my memory says port maneuvers were the "scariest." From full astern to full ahead repeatedly. Of course I couldn't see what was happening from the fireroom, but my imagination always said we about to run something down or hit a dock. Sorry if this is "too much information." |
#4
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On 9/27/13 5:57 PM, Vic Smith wrote:
On Fri, 27 Sep 2013 21:06:13 +0300, injipoint wrote: It's my understanding that nuclear subs are powered by steam turbines which generate electricity for the electric motors that run the propellers. The steam for the turbines comes from the heat of the fission reactor. Lower a few more fuel rods and it doesn't take but a few minutes for the core to heat up and the cooling water temperature rises along with it. Not sure but I think it might take longer. I know they take time to lower the power, like a day or about that but I don't know enough about the process to know the start up bit. I was a USN boilerman on a DDG. Some years ago, but here's how it worked than. Nuke or oil-fired is the means to generate steam in boilers. Whether nuke or oil, steam is steam. Boilers is where it all starts. Steam powers turbines. For main propulsion, generators, and auxiliaries like pumps and forced draft blowers feeding the boilers. Steam also powers evaporators to produce fresh water. Lighting off a cold boiler is the only lengthy process. Took about 2-3 hours on my ship, but since boilers were only "cold iron" in a safe port like Norfolk, Va, they are normally hot and ready and powering the ship even in port. Not much steam demand when not propelling the ship, so they are basically idling. When cold iron in a "safe" port, electric cables and fresh water lines are hooked up to the ship. You need electricity to go from cold iron to a hot boiler. We could probably go from cold iron to "full hot" in less than an hour, but it's better to bring up heat/pressure slowly to avoid heat and expansion shock, so we always took a measured pace, firing only one of the boiler 5 burners. Nowadays steam is dead - except for nukes. As far as I know non-nukes are now all gas turbine, diesel, turbo-diesel, etc. Here's how it works with a steam-powered ships like injipoint observed. I'll use my DDG as an example, but there won't be much variance. Just replace rod movement for "burners." In port a forward and aft boiler are hot and running on one burner each. Each fireroom has 2 boilers, but normally only one is hot. Running all boilers at full power gains very little extra speed. Boilers have scheduled maintenance even underway, and often the idle boiler is open and not operational for this reason. The forward fireroom feeds steam to the forward engineroom main turbines. That runs the starboard shaft. Aft runs aft and port shaft. Even on my ship built in 1961 most boiler controls were automatic. Feed water, oil pressure, etc. The main "humans" operating the boilers were the burner man and the console operator. Operating pressure was 1275 psi. Others on various fireroom watch stations monitored temps and pressures, and were ready to take action for "casualties." When steam demand began dropping pressure, the burnerman manually pushed in another burner, and lit it by pulling down the oil control valve. Oil on a burner was either shut or wide open. The console operator had little to do except adjust oil pressure when demand was low, and adjust "excess" air, to avoid stack smoke. But the console also provided an overview of many systems. So you leave port on maybe 2 of the 5 burners, with low oil pressure. Say you're doing 4 knots. The skipper wants to avoid a bottom structure by backing one screw. Not sure about how the ship is actually controlled, but I've seen this many times. He sends a telegraph command to the engineroom powering that shaft. Can't remember if that comes to the fireroom simultaneously, or the engineroom repeats it. Full astern. The engineroom cranks opens their main throttle, and starts pulling steam. In the fireroom a full astern bell means the burnerman pushes in and light all burners as fast as he can, because all hell will break loose. As steam pressure drops, everything winds up to maintain pressure, It's like banshees screaming. Forced draft blowers, feed pumps, oil pumps, air flow, burners burning, steam flowing. There are limits. The engineroom throttleman isn't supposed to take pressure below 1120 psi. That's the prescribed pressure for boiler shutdown. At sea there's no electricity except that provided by steam. You need the steam to run the pumps to restart the boilers. I've seen it get close, and a couple times warned the throttlemen I was going to shut it down. They listened. My ship was designed for ASW, so we spent a lot of time chasing Soviet subs. We were armed with nuke ASROC missiles. Top speed was 27 knots. We were 4500 tons. But she was geared for ASW, so she would squat and gain speed pretty quickly when you opened the throttles. No roostertail, but a pretty massive stern hump. http://www.navsource.org/archives/05/01003.htm That says top speed 33 knots. Maybe with 4 boilers and overload burner tips. Never did that when I was aboard for 3 1/2 years. 1964-67. Flank speed was 27 knots. We would usually measure speed by screw shaft "turns," not knots. I never heard more than 27 knots mentioned, and can't remember the turns, maybe 40-50 max. Going from 1/3 ahead to full to flank is the usual speed progression of ships. If not done abruptly, there's no real excitement. From dead to flank is a lot of action and noise. From flank to full astern or vice versa is hectic, but only done in open sea during "exercises." It's been a long time, but my memory says port maneuvers were the "scariest." From full astern to full ahead repeatedly. Of course I couldn't see what was happening from the fireroom, but my imagination always said we about to run something down or hit a dock. Sorry if this is "too much information." Wow...terrific post. Thanks. |
#5
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Hi Vic,
I am curious as to the origin of "flank speed". ,, I have never heard of it before and though Wikipedia defines it, there is no reference to the origin o the tem. Cheers Peter |
#6
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#7
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On Sat, 28 Sep 2013 12:31:30 +0300, injipoint
wrote: On 28/09/2013 9:15 AM, wrote: Hi Vic, I am curious as to the origin of "flank speed". ,, I have never heard of it before and though Wikipedia defines it, there is no reference to the origin o the tem. Cheers Peter It's a USN term afaik. If you are protecting a convoy and they turn to avoid a sub, you, the destroyer or frigate, needs to make up considerable ground to get between them, the targets, and the bad guys. You needed to maintain a flank position between the two. I think your sub guys used it in WW2 to move as fast as they could to get to their target positions. Although, in those days, almost anything could outrun a sub. But they sure were hard to find ![]() Sounds right. I can only say for my DDG it wasn't an "emergency" speed as suggested by a Wiki I read. More "tactical." And when sea conditions allowed, all my skippers would use it sometimes for hours on end while in transit, say from the Med back to the U.S. Sure, fuel efficiency suffers, but if you have enough and some to spare to make it to port, or an oiler to rendezvous with, it didn't matter. Warship skippers - at least in the days of cheap oil - were probably no different than the typical power boater in that regard. "Let's get this baby moving!" |
#8
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On Fri, 27 Sep 2013 23:15:23 -0700 (PDT),
wrote: Hi Vic, I am curious as to the origin of "flank speed". ,, I have never heard of it before and though Wikipedia defines it, there is no reference to the origin o the tem. Cheers Peter From www.history.navy.mil Flank Speed One quarter more than standard speed except for cruisers, destroyers, light mine layers and fast aircraft carriers. In cruisers, destroyers, light mine layers and fast aircraft carriers it is ten knots more than standard speed. This is certainly a U.S. term but I don't know whether the royal navy uses the term or not.... so you have an excuse :-) -- Cheers, Bruce in Bangkok |
#9
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Thanks gentlemen; very much appreciated.
I had recently bought and watched the DVD "Convoy, War for the Atlantic", a serious lengthy documentary series produced in England. I'd reccommend it t anyobe both the archive film footage an the information. Although not mentioned in this documentary, a little known fact is that Malaysia's Penang Island was home to a fleet of long range German submarines that preyed upon Allied shipping during WWII. They shared a Japanese submarine base. Apparently the submariners of both countries despsed each other, inly due to the Germans' arrogance and sense of racial superiority. A private outfit has cleared the overgrown jungle that has hidden most of the site and it is now open to visitore. Ciao Peter |
#10
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