Technical Question - Engines - Page 3

mayandlex · 12-15-06, 12:17 AM

Hi CCIP how did the u boats drive 2 propellors with one engine? I understand they were two separate single shafts, one per engine, and that they did not have the ability to connect the shafts, although I think british submarines did have this facility. Did they have a sepatate dynamo and motor per shaft? In any event this would probably be an emergency system as one diesel driving two shafts and props would be less efficient than driving a single shaft surely?

Krupp · 12-15-06, 04:57 AM

from the "Hitler's U-Boat war, The hunters, 1939-1942" - by Clay Blair:

"Stern compartment was known as the electrical room. It contained two 375-horsepower electric motors, or more precisely, motor-generators. The main driveshafts of the diesel engines ran through the core of the motor-generators. When the diesels were operating, either or both motor-generators could be clutched onto the turning driveshafts to serve as generators to charge the batteries. Or, as a fuel-saving (and range-extending) measure, the power produced by one motor-generator, operated by one diesel engine, could be routed to the other motor-generator to turn the other shaft (so rigged, the maximum cruising speed was a leisury 6 knots). Upon diving, when both diesels were shut down, the motor-generators were clutched to the driveshafts, drawing power from the batteries."

So the german U-Boats could drive two prop-shafts with one diesel engine when other diesel powered the generator to charge batteries.

mayandlex · 12-15-06, 02:55 PM

Interesting subject, thanks for the info but surely if say the port deisel is running the motor as a generator while clutched through to the propshaft to drive this and the starboard diesel is driving the motor as a generator to charge batteries then how can it also act as a motor to drive the prop shaft? My reading in this is that each motor can only do one or the other tasks but certainly not both at once. I think this was a flaw in the basic design but the system was very robust, simple and efficient.
British boats shafted through a gearbox arrangement and could run both shafts off one engine using gears, and of course US boats had separate generators and motors on each shaft with no shaft connection between them.

RoDent · 01-22-07, 02:12 PM

Simple question:
Does the speed matter when recharging batteries?
What i mean is that if you go
"ahead standard".... do they charge at normal rate compared to lets say... "ahead flank"= full/maximum recharge rate?
Or do they all charge at same rate irregardless of your speed settings?

Mooncatt · 01-22-07, 02:29 PM

i would say the faster u run the engine the faster the recharge rate.

also just going back a little....whats the point of running diesel underwater even with a snorkel, wouldnt it give ya position away really easy even if you wasnt attacking anything

johnno74 · 01-22-07, 03:35 PM

No when you in recharging batteries only one engine (and one prop) are used for propultion - the other engine is disconnected from the prop and used to charge batteries, at constant RPM. You can verify this by looking at the port/stbd engine RPM dials in the control room when you are on the surface charging batteries - one engine is stopped, the other stays at 500rpm (or something)

Brag · 01-22-07, 04:50 PM

Quote:

Originally Posted by E.B. Fluckey

I toured the Clamagore (SS-343) at Patriot's Point, South Carolina. This sub was commissioned in 1945 - too late to see action in WWII. Anyhow...I was talking to one of the vets on the sub (not sure if he was a submarine vet) and he claimed the sub is always powered by electric motors. I'm a bit skeptical so perhaps someone can clear these questions up.

1. When surfaced does the submarine use electric motors?
2. If so, when surfaced is the current to run the electric motors drawn from the batteries?
3. Or is the current drawn directly from the generators when surfaced?

WWII era American subs were powered with Diesel-electric engines like the ones in diesel-electric locomotives. On the surface the diesels drove the electric motors directly and were disconnected from the electrics when submerged. The electrics then drew power from the batteries.

RoDent · 01-24-07, 03:56 PM

Quote:

Originally Posted by mooncatt

i would say the faster u run the engine the faster the recharge rate.

Nope....it charges all the same. However i never noticed this until i searched the forums and found a post about "other unreleased user controls" that you can use while in the game such as Shift + F2 =free movement while in the command room.

Now when i did the free movement and looked around it showed the starboard engine at a constant 550 RPM while charging irregardless of current speed settings.

Thanks for the reply M8.
Eventhough i've been playing this game for approx 2yrs on a regular basis i still consider myself a swabbie when it comes to tech stuff and info.

Sailor Steve · 01-24-07, 05:12 PM

Quote:

Originally Posted by mooncatt

also just going back a little....whats the point of running diesel underwater even with a snorkel, wouldnt it give ya position away really easy even if you wasnt attacking anything

When using the diesels underwater you're not draining the batteries, hence there is theoretically no reason to surface and recharge.

swuboo · 01-24-07, 05:54 PM

Quote:

Originally Posted by AVGWarhawk

This game does not allow you to run electrics on the surface.

A fact which I discovered one day when I ran out of diesel 50km outside of Wilhelmshaven.

I had to sail into harbor submerged.

carlos26 · 01-24-07, 06:49 PM

Quote:

Originally Posted by Tachyon

1) a)Why are diesel engines used by Submarines on the surface? Why not Electric?
b)Again, why electric underwater...why not diesel?

2) Can ships use Electric engines? (WW2 era)

Hi...
Well you got a lot of answers for the 1a 1b questions... About question 2 Yes... The sips in the WW2 era could have electric engines as the main motion source and they had... For example two american carriers Lexington and Saratoga had combined steam turbine and electric drive... The boilers were used to generate steam, the steam powered turbines, turbines' shafts were connected to electric generator, and they powered slow rotating electric motors... This solution is great for ships with fixed propelers so you dont have problems with stoping, starting, reversing engines with internal combustion... Well i don't want to be boring so i think i'll stop writing right now... And sorry for my english but it's not my native language

AS · 01-25-07, 10:42 AM

Hi, interesting topic. I know about U-Boat engines/motors, but I didn´t know about the US-subs. What is the advantage (or disadvantage) of the US-subs diesel-electric system? And why is it that they had 8 engines altogether?

Seems strange that they spent so much money (and manpower) on such a redundance...

Thanks for replies, AS

12-15-06, 04:57 AM	#32
Krupp Weps Join Date: Nov 2005 Posts: 351 Downloads: 0 Uploads: 0	from the "Hitler's U-Boat war, The hunters, 1939-1942" - by Clay Blair: "Stern compartment was known as the electrical room. It contained two 375-horsepower electric motors, or more precisely, motor-generators. The main driveshafts of the diesel engines ran through the core of the motor-generators. When the diesels were operating, either or both motor-generators could be clutched onto the turning driveshafts to serve as generators to charge the batteries. Or, as a fuel-saving (and range-extending) measure, the power produced by one motor-generator, operated by one diesel engine, could be routed to the other motor-generator to turn the other shaft (so rigged, the maximum cruising speed was a leisury 6 knots). Upon diving, when both diesels were shut down, the motor-generators were clutched to the driveshafts, drawing power from the batteries." So the german U-Boats could drive two prop-shafts with one diesel engine when other diesel powered the generator to charge batteries. __________________ "Gentlemen, we have no choice. Total engagement. Die with dignity."

01-22-07, 02:12 PM	#34
RoDent Swabbie Join Date: Jun 2005 Location: Grid BA74 Posts: 8 Downloads: 0 Uploads: 0	recharging batteries SH3 Simple question: Does the speed matter when recharging batteries? What i mean is that if you go "ahead standard".... do they charge at normal rate compared to lets say... "ahead flank"= full/maximum recharge rate? Or do they all charge at same rate irregardless of your speed settings?

01-22-07, 02:29 PM	#35
Mooncatt Grey Wolf Join Date: Jun 2006 Location: Keighley UK Posts: 938 Downloads: 78 Uploads: 0	i would say the faster u run the engine the faster the recharge rate. also just going back a little....whats the point of running diesel underwater even with a snorkel, wouldnt it give ya position away really easy even if you wasnt attacking anything __________________

01-25-07, 10:42 AM	#42
AS 中国水兵 Join Date: Jan 2004 Location: Germany Posts: 275 Downloads: 135 Uploads: 0	Hi, interesting topic. I know about U-Boat engines/motors, but I didn´t know about the US-subs. What is the advantage (or disadvantage) of the US-subs diesel-electric system? And why is it that they had 8 engines altogether? Seems strange that they spent so much money (and manpower) on such a redundance... Thanks for replies, AS __________________ Whenever people agree with me I always feel I must be wrong. (Oscar Wilde)

12-15-06, 12:17 AM	#31
mayandlex A-ganger Join Date: Nov 2005 Location: New Zealand Posts: 74 Downloads: 106 Uploads: 0	Hi CCIP how did the u boats drive 2 propellors with one engine? I understand they were two separate single shafts, one per engine, and that they did not have the ability to connect the shafts, although I think british submarines did have this facility. Did they have a sepatate dynamo and motor per shaft? In any event this would probably be an emergency system as one diesel driving two shafts and props would be less efficient than driving a single shaft surely?

12-15-06, 02:55 PM	#33
mayandlex A-ganger Join Date: Nov 2005 Location: New Zealand Posts: 74 Downloads: 106 Uploads: 0	Interesting subject, thanks for the info but surely if say the port deisel is running the motor as a generator while clutched through to the propshaft to drive this and the starboard diesel is driving the motor as a generator to charge batteries then how can it also act as a motor to drive the prop shaft? My reading in this is that each motor can only do one or the other tasks but certainly not both at once. I think this was a flaw in the basic design but the system was very robust, simple and efficient. British boats shafted through a gearbox arrangement and could run both shafts off one engine using gears, and of course US boats had separate generators and motors on each shaft with no shaft connection between them.

01-22-07, 03:35 PM	#36
johnno74 Planesman Join Date: Nov 2006 Location: Melbourne, Australia Posts: 197 Downloads: 5 Uploads: 0	No when you in recharging batteries only one engine (and one prop) are used for propultion - the other engine is disconnected from the prop and used to charge batteries, at constant RPM. You can verify this by looking at the port/stbd engine RPM dials in the control room when you are on the surface charging batteries - one engine is stopped, the other stays at 500rpm (or something)