Cruise Speed

BenG · 06-13-06, 06:39 AM

I'm just wondering what Cruise speed people use (and which is the best/most realistic) when sailing to and from Patrol Zones, and when just searching (i.e. not sailing to a contact).

I use 10 Knots on a Type VII (this is shown as ahead 1/3 (2nd Notch) on the telegraph).

Rose · 06-13-06, 06:44 AM

Haha I'm not sure how many times this has been asked -- but its been alot. Let me give it a go. For very long cruises I want to have the opportunity to make my patrol as long as possible to give me time and distance to intercept long range targets, get home if damaged, etc. So I like to go Ahead Slow at PD from sunrise till midnight. At 0000 hours, I surface to charge batts and reload fish, etc. I dive again at dawn, about 0600 hours. This tactic saves me alot of precious fuel. I'm pretty sure its realistic too, though I wouldn't bet my lifes savings on it.

For shorter Type II North Sea cruises, I use Ahead Standard and 1/3.

JScones · 06-13-06, 07:14 AM

Someone (Sailor Steve? jaxa?) created a pretty chart a while ago that mapped cruising speed v distance travelled. I think travelling at 9kts was determined to provide the best efficiency.

U-Bones · 06-13-06, 07:21 AM

Quote:

Originally Posted by Rose

Haha I'm not sure how many times this has been asked -- but its been alot. Let me give it a go. For very long cruises I want to have the opportunity to make my patrol as long as possible to give me time and distance to intercept long range targets, get home if damaged, etc. So I like to go Ahead Slow at PD from sunrise till midnight. At 0000 hours, I surface to charge batts and reload fish, etc. I dive again at dawn, about 0600 hours. This tactic saves me alot of precious fuel. I'm pretty sure its realistic too, though I wouldn't bet my lifes savings on it.

For shorter Type II North Sea cruises, I use Ahead Standard and 1/3.

You are wise in your betting, and dead on with the ahead slow, but the submerged thing: you would need to max surface time for realistic mileage miser mode.

If this were realistic, everyone would be running generators to charge the batteries their cars run on. Unfortunately, energy is -always- lost when you convert from one form to another.

In game though, it IS more efficient

Rose · 06-13-06, 07:47 AM

So you think Ahead Slow on the surface 100% of the time (early war I'm assuming) is the best bet? And JScones, you think 9 knots is best?

JScones · 06-13-06, 07:59 AM

I don't know if 9kts is "best", I was just impressed with the chart and analysis undertaken some ways back. It convinced me. I travel at 9kts surfaced all the time. Hopefully someone here with a better memory than me will remember the related thread's contents.

cobalt · 06-13-06, 09:10 AM

by running at ahead slow and submerging at night (its mid1942, best tactic for me right now) i can save the fuel reserve for a couple months in a viic

06-13-06, 10:28 AM

Quote:

Originally Posted by JScones

Someone (Sailor Steve? jaxa?) created a pretty chart a while ago that mapped cruising speed v distance travelled. I think travelling at 9kts was determined to provide the best efficiency.

T'wasn't me. I always go at Ahead 1/3 when travelling. Once at my patrol zone I use Ahead Slow. Curious thing, though: using the NASA Battery Fix I noticed that a Type II can't do more than about 12 hours at Ahead Slow submerged, but if I manually set it for 2 knots it lasts way more than 24 hours.

Threadfin · 06-13-06, 10:53 AM

I've done alot of testing, and a setting of just barely above slow is most efficient IMO. Using the navigator to report range you can see it. What I do is set ahead slow, then click the speed dial just barely above the current speed. Let's say ahead slow gives 8 kts. I then click the speed dial on 9kts. The speed stays at 8kts (sounds confusing I know), but the range increases by about 2000km (in type VII with GW engine).

The most efficient speed is also a function of which engine you have installed on your boat I have found.

Test it for your self. Set ahead slow just after leaving port, and run at relatively high compression to give reliable results (no speed change due to wave action etc). Click the navigator and check his range estimate, get several readings to get a good sample.

Now click the speed dial (not the telegraph) maybe a half knot or a full knot over the ahead slow speed and get some more range reports from the navigator. If you results are like mine, your most efficient speed will be just above ahead slow.

Cobalt~ I'm curious why you submerge at night instead of during the daytime? That's opposite of what I might do. Just interested in your reasoning.

U-Bones · 06-13-06, 12:04 PM

12 hours @ 2kt submerged = 24kt traveled.

-2kt for ~4 hours charging to fully charge = 8kts less traveled in return for the 24 on battery. Your batteries may charge in more or less, but you get the point. If you are running on fumes, submerge when you are not charging.

Keelbuster · 06-13-06, 12:54 PM

I go ahead slow if i'm crossing the ocean. It feels efficient. Ahead 1/3rd feels slightly less efficient. But, I use a Type VII so I rarely have to go that far. If I do, I can cross the atlantic (to the carribean) using about 1/3 of my fuel reserve, giving me 1/3 to mess around and 1/3 to get back. But I wouldn't make the crossing if I didnt' have a Utanker to dock up with. It's just not worth it. For local hunting in the Western approaches, I don't need much fuel. I almost always return with about a half tank - that's with extended searching, and multiple flank overhauls. Fuel just isn't that important. My torps always run out first.

Kb

Egan · 06-13-06, 01:54 PM

Quote:

Originally Posted by Rose

Haha I'm not sure how many times this has been asked -- but its been alot. Let me give it a go. For very long cruises I want to have the opportunity to make my patrol as long as possible to give me time and distance to intercept long range targets, get home if damaged, etc. So I like to go Ahead Slow at PD from sunrise till midnight. At 0000 hours, I surface to charge batts and reload fish, etc. I dive again at dawn, about 0600 hours. This tactic saves me alot of precious fuel. I'm pretty sure its realistic too, though I wouldn't bet my lifes savings on it.

For shorter Type II North Sea cruises, I use Ahead Standard and 1/3.

Standard practice at least up until later on in the war was for U-boats to travel on the surface as much as possible for a variety of reason. Your speeds are sensible and they are pretty much the ones I use. I sometimes knock the speed down by a couple of knots to simulate running on only one deisel engine which was was fairly common practice in real life but not possible in the game. When I am in my patrol area I tend to travel a 3 or 4 knots. its amazing how much fuel you can save by adjusting the exact speed.

CCIP · 06-13-06, 01:57 PM

It's easy to tell what's best, just look at the max distance :p

Unless I'm in a rush, or the patrol is not all that distant, 'slow' is always my speed of choice. I think any Type IX captain should be used to it by now - you need to be able to exploit every inch that boat can travel in far-away waters!

Rosencrantz · 06-13-06, 02:43 PM

Egan wrote:

Quote:

When I am in my patrol area I tend to travel a 3 or 4 knots.

Just thinking that simulating driving with just one diesel by dropping your speed to 4 knots. I'm not totally sure if this is realism if talking about VII or IX boats. Schaeffer (Cmdr of U977) wrote 6 knots was slowest speed ahead VII could go on the surface. It's not mentioned if that was done with one or two diesels, so I just assume he must be talking about using just one engine. (The boat was getting close to Norway coast in the darknes and they wanted drive as slow as possible).

So I think it's very much possible Dev's didn't gave a single thought on that one diesel / two diesel thing at all when adjusting engine orders and speed releated.

Greetings,
-RC-

robj250 · 06-13-06, 02:51 PM

Wow, I guess I am doing it all wrong then as I run on the surface with my VIIB at ahead standard. So I should be running at ahead slow on the surface?

06-13-06, 06:39 AM	#1
BenG Watch Join Date: May 2006 Posts: 30 Downloads: 4 Uploads: 0	Cruise Speed I'm just wondering what Cruise speed people use (and which is the best/most realistic) when sailing to and from Patrol Zones, and when just searching (i.e. not sailing to a contact). I use 10 Knots on a Type VII (this is shown as ahead 1/3 (2nd Notch) on the telegraph). __________________ -Ben Intel Dual Core @ 2.13 GHz (= 4.26 GHz (or so it is claimed!) 4 GB RAM (but due to 32-bit limitation I only get 3.074 GB) Windows Vista (a few compatability issues to begin with but works for me now)

06-13-06, 10:53 AM	#9
Threadfin Ace of the Deep Join Date: Feb 2006 Posts: 1,163 Downloads: 38 Uploads: 0	I've done alot of testing, and a setting of just barely above slow is most efficient IMO. Using the navigator to report range you can see it. What I do is set ahead slow, then click the speed dial just barely above the current speed. Let's say ahead slow gives 8 kts. I then click the speed dial on 9kts. The speed stays at 8kts (sounds confusing I know), but the range increases by about 2000km (in type VII with GW engine). The most efficient speed is also a function of which engine you have installed on your boat I have found. Test it for your self. Set ahead slow just after leaving port, and run at relatively high compression to give reliable results (no speed change due to wave action etc). Click the navigator and check his range estimate, get several readings to get a good sample. Now click the speed dial (not the telegraph) maybe a half knot or a full knot over the ahead slow speed and get some more range reports from the navigator. If you results are like mine, your most efficient speed will be just above ahead slow. Cobalt~ I'm curious why you submerge at night instead of during the daytime? That's opposite of what I might do. Just interested in your reasoning. __________________ What? Behind the rabbit?

06-13-06, 12:54 PM	#11
Keelbuster Ace of the Deep Join Date: Oct 2005 Location: BA 72 Posts: 1,092 Downloads: 43 Uploads: 0	I go ahead slow if i'm crossing the ocean. It feels efficient. Ahead 1/3rd feels slightly less efficient. But, I use a Type VII so I rarely have to go that far. If I do, I can cross the atlantic (to the carribean) using about 1/3 of my fuel reserve, giving me 1/3 to mess around and 1/3 to get back. But I wouldn't make the crossing if I didnt' have a Utanker to dock up with. It's just not worth it. For local hunting in the Western approaches, I don't need much fuel. I almost always return with about a half tank - that's with extended searching, and multiple flank overhauls. Fuel just isn't that important. My torps always run out first. Kb __________________

06-13-06, 01:57 PM	#13
CCIP Navy Seal Join Date: Apr 2005 Location: Waterloo, Canada Posts: 8,700 Downloads: 29 Uploads: 2	It's easy to tell what's best, just look at the max distance :p Unless I'm in a rush, or the patrol is not all that distant, 'slow' is always my speed of choice. I think any Type IX captain should be used to it by now - you need to be able to exploit every inch that boat can travel in far-away waters! __________________ There are only forty people in the world and five of them are hamburgers. -Don Van Vliet (aka Captain Beefheart)

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06-13-06, 06:44 AM	#2
Rose Grey Wolf Join Date: May 2006 Location: New York City Posts: 966 Downloads: 0 Uploads: 0	Haha I'm not sure how many times this has been asked -- but its been alot. Let me give it a go. For very long cruises I want to have the opportunity to make my patrol as long as possible to give me time and distance to intercept long range targets, get home if damaged, etc. So I like to go Ahead Slow at PD from sunrise till midnight. At 0000 hours, I surface to charge batts and reload fish, etc. I dive again at dawn, about 0600 hours. This tactic saves me alot of precious fuel. I'm pretty sure its realistic too, though I wouldn't bet my lifes savings on it. For shorter Type II North Sea cruises, I use Ahead Standard and 1/3.

06-13-06, 07:14 AM	#3
JScones Navy Seal Join Date: Apr 2005 Posts: 5,501 Downloads: 19 Uploads: 0	Someone (Sailor Steve? jaxa?) created a pretty chart a while ago that mapped cruising speed v distance travelled. I think travelling at 9kts was determined to provide the best efficiency.

06-13-06, 07:47 AM	#5
Rose Grey Wolf Join Date: May 2006 Location: New York City Posts: 966 Downloads: 0 Uploads: 0	So you think Ahead Slow on the surface 100% of the time (early war I'm assuming) is the best bet? And JScones, you think 9 knots is best?

06-13-06, 07:59 AM	#6
JScones Navy Seal Join Date: Apr 2005 Posts: 5,501 Downloads: 19 Uploads: 0	I don't know if 9kts is "best", I was just impressed with the chart and analysis undertaken some ways back. It convinced me. I travel at 9kts surfaced all the time. Hopefully someone here with a better memory than me will remember the related thread's contents.

06-13-06, 09:10 AM	#7
cobalt Commander Join Date: May 2006 Posts: 440 Downloads: 21 Uploads: 0	by running at ahead slow and submerging at night (its mid1942, best tactic for me right now) i can save the fuel reserve for a couple months in a viic

06-13-06, 12:04 PM	#10
U-Bones Grey Wolf Join Date: Mar 2005 Location: Treading Water Posts: 847 Downloads: 56 Uploads: 0	12 hours @ 2kt submerged = 24kt traveled. -2kt for ~4 hours charging to fully charge = 8kts less traveled in return for the 24 on battery. Your batteries may charge in more or less, but you get the point. If you are running on fumes, submerge when you are not charging.

06-13-06, 02:51 PM	#15
robj250 Sea Lord Join Date: Mar 2006 Location: Port Hardy, BC, Canada 75 yo with M.S. & C.O.P.D. & heart problems Posts: 1,930 Downloads: 1 Uploads: 0	Wow, I guess I am doing it all wrong then as I run on the surface with my VIIB at ahead standard. So I should be running at ahead slow on the surface?