Fuel or Speed

NZsnowman · 01-19-07, 06:12 PM

I have always wondered what U-Boat Caption did during the war on the way back to base after a patrol.

a) Travel back to base as fast as they could, base on there able fuel to minmum the turn-a-round between patrols.

or...

b) Travel back at slower speeeds to safe fuel for the war.

Which was more important, saving fuel or a quicker turn-a-round?

Letum · 01-19-07, 06:27 PM

Usually fuel.
You would almost always go at the most fuel efficient speed (~7knts) if you are not chasing something or running away from something. This is still the case, even if you have 80% fuel, but no torps. You Still go home at cruising speed.
A) Fuel is expensive.
B) The motors will have a longer life.

Exceptions where made in dangerous waters (Biscay post '42).

bigboywooly · 01-19-07, 06:51 PM

Yep fuel efficiency is the most important
Most boats returned home with no fuel but plenty of torpedos
Quite the opposite of SH3

_Seth_ · 01-20-07, 11:11 AM

I read somewhere that 9 kts was the most fuel efficient speed..Is it? Does this vary depending on the boat you have + equipment?

Jimbuna · 01-20-07, 11:16 AM

Good question Seth

Despite the number of times this topic has come up I'm not sure anyone has come up with a definitive answer :hmm:

Sailor Steve · 01-20-07, 11:19 AM

I always set for two-thirds, which is around 9 knots in a VII and 7 knots in a II. I could be wrong but I'm a trusting innocent soul and I'm also lazy.

Letum · 01-20-07, 11:48 AM

7knts is the only value I can find with historical references.

In SHIII on a VIIC with no engine modifications the ideal speed in perfect weather is about 7.5 - 8 knts.

I have not studied how this changes with different boats / engines / weather.

Respenus · 01-20-07, 12:09 PM

I'd say fuel. You can't get home without it. So unless you have a big jussy target/convoy to blow to kingdom come, you stay put at the optimal speed!

fredbass · 01-20-07, 12:15 PM

Though it varies some, when surfaced and you're batteries are back up to 100%, you can have the Navigator check your maximum range at current speed and you'll get a fairly good idea of what you're working with.

01-19-07, 06:12 PM	#1
NZsnowman Machinist's Mate Join Date: Mar 2005 Location: New Zealand Posts: 127 Downloads: 6 Uploads: 0	Fuel or Speed I have always wondered what U-Boat Caption did during the war on the way back to base after a patrol. a) Travel back to base as fast as they could, base on there able fuel to minmum the turn-a-round between patrols. or... b) Travel back at slower speeeds to safe fuel for the war. Which was more important, saving fuel or a quicker turn-a-round?

01-19-07, 06:27 PM	#2
Letum Navy Seal Join Date: Feb 2005 Location: York - UK Posts: 6,079 Downloads: 43 Uploads: 0	Usually fuel. You would almost always go at the most fuel efficient speed (~7knts) if you are not chasing something or running away from something. This is still the case, even if you have 80% fuel, but no torps. You Still go home at cruising speed. A) Fuel is expensive. B) The motors will have a longer life. Exceptions where made in dangerous waters (Biscay post '42). __________________

01-19-07, 06:51 PM	#3
bigboywooly Rear Admiral Join Date: Apr 2006 Location: Swindon, England Posts: 10,151 Downloads: 35 Uploads: 0	Yep fuel efficiency is the most important Most boats returned home with no fuel but plenty of torpedos Quite the opposite of SH3 __________________ My mediafire page http://www.mediafire.com/?11eoq19bq9r41

01-20-07, 11:11 AM	#4
_Seth_ Ocean Warrior Join Date: Dec 2005 Location: In Tromsoe, @Tirpitz' final resting place.. Posts: 3,277 Downloads: 94 Uploads: 0	I read somewhere that 9 kts was the most fuel efficient speed..Is it? Does this vary depending on the boat you have + equipment? __________________

01-20-07, 11:16 AM	#5
Jimbuna Chief of the Boat Join Date: Feb 2006 Location: 250 metres below the surface Posts: 190,473 Downloads: 63 Uploads: 13	Good question Seth Despite the number of times this topic has come up I'm not sure anyone has come up with a definitive answer :hmm: __________________ Wise men speak because they have something to say; Fools because they have to say something. Oh my God, not again!!

01-20-07, 11:19 AM	#6
Sailor Steve Eternal Patrol Join Date: Nov 2002 Location: High in the mountains of Utah Posts: 50,369 Downloads: 745 Uploads: 249	I always set for two-thirds, which is around 9 knots in a VII and 7 knots in a II. I could be wrong but I'm a trusting innocent soul and I'm also lazy. __________________ “Never do anything you can't take back.” —Rocky Russo

01-20-07, 11:48 AM	#7
Letum Navy Seal Join Date: Feb 2005 Location: York - UK Posts: 6,079 Downloads: 43 Uploads: 0	7knts is the only value I can find with historical references. In SHIII on a VIIC with no engine modifications the ideal speed in perfect weather is about 7.5 - 8 knts. I have not studied how this changes with different boats / engines / weather. __________________

01-20-07, 12:09 PM	#8
Respenus Ace of the Deep Join Date: Sep 2006 Posts: 1,169 Downloads: 0 Uploads: 0	I'd say fuel. You can't get home without it. So unless you have a big jussy target/convoy to blow to kingdom come, you stay put at the optimal speed! __________________

01-20-07, 12:15 PM	#9
fredbass Ace of the Deep Join Date: Feb 2006 Location: New Port Richey, Fl, USA Posts: 1,066 Downloads: 0 Uploads: 0	Though it varies some, when surfaced and you're batteries are back up to 100%, you can have the Navigator check your maximum range at current speed and you'll get a fairly good idea of what you're working with. __________________