Optimum Speed in Patrol Grid?

Stiebler · 10-14-06, 10:19 AM

What is the optimum speed for patrolling your assigned grid square (eg BE65)?

The two plausible alternatives seem to be:
a) at one-third ahead (most efficient fuel setting to make progress);
b) at slow ahead (consumes least fuel to maximise time in grid).
[Alternative (c) - to use no fuel at all by remaining stopped - would not be permitted by BdU, since it endangers the boat in case of sudden air attack.]

If the target merchant ships appear truly randomly and instantaneously in the square, then there is no difference between (a) and (b), except that (b) will allow you to remain longer in the patrol grid.

However, the merchant ships do not appear randomly and suddenly. They move slowly through the patrol grid square. Moving faster through the grid may increase the chance of locating them as they move. Or it may take you away from the targets faster.

I'd guess that the answer depends on the (average) relative speeds of U-boat and target.

Quite an interesting statistical, or mathematical-modelling, exercise.
Does anyone already know the answer?

[Incidentally, wolf-packs patrolling the Atlantic moved at slowest speed in their grid, to conserve fuel. But they relied on their U-boat neighbours to patrol their flanks so that nothing could slip through. Their solution doesn't necessarily apply to a lone-wolf U-boat, as in SH3.]

Stiebler.

Sailor Steve · 10-14-06, 10:54 AM

I always move at slow, to conserve fuel. I assume I have food for two months in a Type VII and try not to head for home until 50-60 days have passed. Of course if you're lucky you'll run out of torpedoes long before that...

Deimos01 · 10-14-06, 11:38 AM

I run at 1/3rd once I hit my grid. No use wasting fuel. Save that for chasing down convoys. When making contact with an unreported lone ship or convoy it is pretty much a matter of being in the right place at the right time and speed wont change that. Save yer fuel!

Coda · 10-14-06, 12:27 PM

I stay submerged at 1/3 untill I use 20% of my battery, then surface and recharge at ahead slow. After charged, I go back down.

Reason I do this is the ability to hear much farther then see. It also save a ton of fuel.

GT182 · 10-14-06, 01:51 PM

I use 1/3 for the same reason as Deimos01 says. Plus 1/3 consumes more time for the required 24 hours. Now that I have a snorkel for my D2 I usually patrol submerged. If I come across a warship, they have less of a chance seeing us and we have a better chance of escaping if detected.

Stiebler · 10-16-06, 03:26 AM

Many thanks for these replies, but unfortunately they state only how the respondents *do* patrol their grid areas, not how they *ought* to patrol their grid areas.

I've carried out a computer modelling simulation.

Results in the sticky NYGM Research thread:
http://www.subsim.com/radioroom/show...5&postcount=66

Stiebler.

Tobus · 10-16-06, 01:08 PM

I go slow wherever I go, only using higher speeds in attacks. With slow speed, A VII can go from Kiel to New York and back with some fuel to spare.

In my patrolgrid I usually go under to 50 meters on slow speed, since you can hear much farther then you can see.

Zero Niner · 10-16-06, 08:06 PM

My cruising speed, to the patrol area and within the grid itself, is 1/3.
I use faster speeds only to intercept targets, leave a dangerous area, or returning to port - if fuel situation allows.
I normally exhaust my torps before fuel becomes an issue (I'm a Type VII user).

10-14-06, 10:19 AM	#1
Stiebler Fuel Supplier Join Date: Oct 2005 Location: London, UK Posts: 1,237 Downloads: 29 Uploads: 4	Optimum Speed in Patrol Grid? What is the optimum speed for patrolling your assigned grid square (eg BE65)? The two plausible alternatives seem to be: a) at one-third ahead (most efficient fuel setting to make progress); b) at slow ahead (consumes least fuel to maximise time in grid). [Alternative (c) - to use no fuel at all by remaining stopped - would not be permitted by BdU, since it endangers the boat in case of sudden air attack.] If the target merchant ships appear truly randomly and instantaneously in the square, then there is no difference between (a) and (b), except that (b) will allow you to remain longer in the patrol grid. However, the merchant ships do not appear randomly and suddenly. They move slowly through the patrol grid square. Moving faster through the grid may increase the chance of locating them as they move. Or it may take you away from the targets faster. I'd guess that the answer depends on the (average) relative speeds of U-boat and target. Quite an interesting statistical, or mathematical-modelling, exercise. Does anyone already know the answer? [Incidentally, wolf-packs patrolling the Atlantic moved at slowest speed in their grid, to conserve fuel. But they relied on their U-boat neighbours to patrol their flanks so that nothing could slip through. Their solution doesn't necessarily apply to a lone-wolf U-boat, as in SH3.] Stiebler.

10-14-06, 10:54 AM	#2
Sailor Steve Eternal Patrol Join Date: Nov 2002 Location: High in the mountains of Utah Posts: 50,369 Downloads: 745 Uploads: 249	I always move at slow, to conserve fuel. I assume I have food for two months in a Type VII and try not to head for home until 50-60 days have passed. Of course if you're lucky you'll run out of torpedoes long before that... __________________ “Never do anything you can't take back.” —Rocky Russo

10-14-06, 01:51 PM	#5
GT182 Ocean Warrior Join Date: May 2005 Location: New Castle of Delaware Posts: 3,231 Downloads: 658 Uploads: 0	I use 1/3 for the same reason as Deimos01 says. Plus 1/3 consumes more time for the required 24 hours. Now that I have a snorkel for my D2 I usually patrol submerged. If I come across a warship, they have less of a chance seeing us and we have a better chance of escaping if detected. __________________ Gary No Borders, No Language, No Culture =s No Country I'm a Deplorable, and proud of it.

10-14-06, 11:38 AM	#3
Deimos01 Frogman Join Date: Feb 2005 Location: St louis Posts: 304 Downloads: 18 Uploads: 0	I run at 1/3rd once I hit my grid. No use wasting fuel. Save that for chasing down convoys. When making contact with an unreported lone ship or convoy it is pretty much a matter of being in the right place at the right time and speed wont change that. Save yer fuel!

10-14-06, 12:27 PM	#4
Coda Medic Join Date: Oct 2006 Posts: 159 Downloads: 0 Uploads: 0	I stay submerged at 1/3 untill I use 20% of my battery, then surface and recharge at ahead slow. After charged, I go back down. Reason I do this is the ability to hear much farther then see. It also save a ton of fuel.

10-16-06, 03:26 AM	#6
Stiebler Fuel Supplier Join Date: Oct 2005 Location: London, UK Posts: 1,237 Downloads: 29 Uploads: 4	Many thanks for these replies, but unfortunately they state only how the respondents do patrol their grid areas, not how they ought to patrol their grid areas. I've carried out a computer modelling simulation. Results in the sticky NYGM Research thread: http://www.subsim.com/radioroom/show...5&postcount=66 Stiebler.

10-16-06, 01:08 PM	#7
Tobus Lieutenant Join Date: Jun 2005 Posts: 260 Downloads: 13 Uploads: 0	I go slow wherever I go, only using higher speeds in attacks. With slow speed, A VII can go from Kiel to New York and back with some fuel to spare. In my patrolgrid I usually go under to 50 meters on slow speed, since you can hear much farther then you can see.

10-16-06, 08:06 PM	#8
Zero Niner Ace of the Deep Join Date: Apr 2005 Posts: 1,033 Downloads: 69 Uploads: 0	My cruising speed, to the patrol area and within the grid itself, is 1/3. I use faster speeds only to intercept targets, leave a dangerous area, or returning to port - if fuel situation allows. I normally exhaust my torps before fuel becomes an issue (I'm a Type VII user).