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Ship endurance
Posted: Wed Nov 04, 2009 5:52 pm
by akdreemer
Found this at Hyperwar and thought I would share. It gives the wartime endurance for most of the US warships in WWII.
http://www.ibiblio.org/hyperwar/USN/ref/Fuel/index.html
In most cases these figures vary significantly from stock game values.
RE: Ship endurance
Posted: Wed Nov 04, 2009 8:28 pm
by RevRick
Hmmmm... The CV Saratoga... A RADIUS of 8,200 miles at 15 Kt (typical TF Cruising Speed), a RADIUS of 4020 miles at 25 Kt. (probably equates to Mission speed if at mission speed the whole time), and Radius of 2360 at 30 Kt. (probably as fast as a TF would driven, and that only for sprinting into a zone...at any rate much farther than she could steam in one night, by at least a factor of five!)
RE: Ship endurance
Posted: Thu Nov 05, 2009 7:21 am
by herwin
ORIGINAL: RevRick
Hmmmm... The CV Saratoga... A RADIUS of 8,200 miles at 15 Kt (typical TF Cruising Speed), a RADIUS of 4020 miles at 25 Kt. (probably equates to Mission speed if at mission speed the whole time), and Radius of 2360 at 30 Kt. (probably as fast as a TF would driven, and that only for sprinting into a zone...at any rate much farther than she could steam in one night, by at least a factor of five!)
Radius was about 40% of range.
The USN did 30 knots sustained for strategic moves of CVTFs between the South Pacific and Hawaii and also between Hawaii and the West Coast. The problem was that the DDs couldn't keep up; the cruisers could.
RE: Ship endurance
Posted: Thu Nov 05, 2009 2:40 pm
by Shark7
ORIGINAL: herwin
ORIGINAL: RevRick
Hmmmm... The CV Saratoga... A RADIUS of 8,200 miles at 15 Kt (typical TF Cruising Speed), a RADIUS of 4020 miles at 25 Kt. (probably equates to Mission speed if at mission speed the whole time), and Radius of 2360 at 30 Kt. (probably as fast as a TF would driven, and that only for sprinting into a zone...at any rate much farther than she could steam in one night, by at least a factor of five!)
Radius was about 40% of range.
The USN did 30 knots sustained for strategic moves of CVTFs between the South Pacific and Hawaii and also between Hawaii and the West Coast. The problem was that the DDs couldn't keep up; the cruisers could.
Exactly, it is the same with aircraft. To expand on what herwin has pointed out: They try to keep at least a 10% fuel reserve on any given mission. The radius is half the range at the 80-90% fuel expenditure mark.
Combat radius is best described as the fullest range a ship can sail or aircraft can fly while still having at least a 10% fuel reserve when it arrives back at home base.
Also keep in mind that any combat manuevering will drastically reduce the combat radius, as fuel is expended at a higher rate in combat.
RE: Ship endurance
Posted: Thu Nov 05, 2009 6:30 pm
by akdreemer
ORIGINAL: herwin
ORIGINAL: RevRick
Hmmmm... The CV Saratoga... A RADIUS of 8,200 miles at 15 Kt (typical TF Cruising Speed), a RADIUS of 4020 miles at 25 Kt. (probably equates to Mission speed if at mission speed the whole time), and Radius of 2360 at 30 Kt. (probably as fast as a TF would driven, and that only for sprinting into a zone...at any rate much farther than she could steam in one night, by at least a factor of five!)
Radius was about 40% of range.
The USN did 30 knots sustained for strategic moves of CVTFs between the South Pacific and Hawaii and also between Hawaii and the West Coast. The problem was that the DDs couldn't keep up; the cruisers could.
While normally one might equate radius as approximately 40% of range, in this case radius roughly equal to navigational miles/endurance, sans how far a ship can steam until it needs to refuel. The Saratoga had old low pressure machinery as was relatively less efficient than the newer high pressure power plants installed in the war built ships.
RE: Ship endurance
Posted: Thu Nov 05, 2009 6:32 pm
by akdreemer
ORIGINAL: Shark7
ORIGINAL: herwin
ORIGINAL: RevRick
Hmmmm... The CV Saratoga... A RADIUS of 8,200 miles at 15 Kt (typical TF Cruising Speed), a RADIUS of 4020 miles at 25 Kt. (probably equates to Mission speed if at mission speed the whole time), and Radius of 2360 at 30 Kt. (probably as fast as a TF would driven, and that only for sprinting into a zone...at any rate much farther than she could steam in one night, by at least a factor of five!)
Radius was about 40% of range.
The USN did 30 knots sustained for strategic moves of CVTFs between the South Pacific and Hawaii and also between Hawaii and the West Coast. The problem was that the DDs couldn't keep up; the cruisers could.
Exactly, it is the same with aircraft. To expand on what herwin has pointed out: They try to keep at least a 10% fuel reserve on any given mission. The radius is half the range at the 80-90% fuel expenditure mark.
Combat radius is best described as the fullest range a ship can sail or aircraft can fly while still having at least a 10% fuel reserve when it arrives back at home base.
Also keep in mind that any combat manuevering will drastically reduce the combat radius, as fuel is expended at a higher rate in combat.
I suggest you read the report first. In this case radius does not equate to 40% of endurance.
RE: Ship endurance
Posted: Thu Nov 05, 2009 7:38 pm
by JWE
ORIGINAL: AlaskanWarrior
I suggest you read the report first. In this case radius does not equate to 40% of endurance.
AlaskanWarrior is quite correct. The terms "radius" and "range" are subjective, somewhat interchangeable, and not particularly relevant.
The game uses design "fuel miles" at "basis" to determine endurance. Full speed burns 6x the gas as cruise. There are only 2 speeds that apply; 'cruise' and 'full'. Mission speed is a calculated multiple of the two.
RE: Ship endurance
Posted: Sat Nov 07, 2009 3:38 pm
by RevRick
ORIGINAL: JWE
ORIGINAL: AlaskanWarrior
I suggest you read the report first. In this case radius does not equate to 40% of endurance.
AlaskanWarrior is quite correct. The terms "radius" and "range" are subjective, somewhat interchangeable, and not particularly relevant.
The game uses design "fuel miles" at "basis" to determine endurance. Full speed burns 6x the gas as cruise. There are only 2 speeds that apply; 'cruise' and 'full'. Mission speed is a calculated multiple of the two.
Well, according to the tables, that doesn't seem to quite jibe. Keeping equal values from the table - Radius, the cruise speed (15 Kt usually) R=8200. At 30 kt (usually what a TF would call Full speed) the R=2360 - that is a ratio of 3.47:1 vice 6:1. I don't think you can realistically use the Flank Speed indications for each ship as a factor in calculating the ratios because each ship would have a different Flank Speed, which means there wouldn't be much station keeping in formation. Some of the Treaty Battleships could only maintain only 26 kt Flank Speed on a regular basis for that matter. So that would limit formation speed to 25 kt at best to keep the BB's from looking like Old Smokey coming down the home stretch.
RE: Ship endurance
Posted: Sat Nov 07, 2009 4:14 pm
by JWE
ORIGINAL: RevRick
Well, according to the tables, that doesn't seem to quite jibe. Keeping equal values from the table - Radius, the cruise speed (15 Kt usually) R=8200. At 30 kt (usually what a TF would call Full speed) the R=2360 - that is a ratio of 3.47:1 vice 6:1. I don't think you can realistically use the Flank Speed indications for each ship as a factor in calculating the ratios because each ship would have a different Flank Speed, which means there wouldn't be much station keeping in formation. Some of the Treaty Battleships could only maintain only 26 kt Flank Speed on a regular basis for that matter. So that would limit formation speed to 25 kt at best to keep the BB's from looking like Old Smokey coming down the home stretch.
Well, this is a computer game, Rev, and a certain degree of abstraction is to be expected. There are only two speeds in the database, "full" and "cruise". They have to fit every single TF, doing every single mission, on every single day. Gary Grigsby came up with 6x for a consumption rate multiplier for every single TF, for every single nation, over every single year, for every single op posture, over an entire theater of operations.
All things considered, it looks good to me.
RE: Ship endurance
Posted: Sat Nov 07, 2009 9:00 pm
by akdreemer
ORIGINAL: RevRick
ORIGINAL: JWE
ORIGINAL: AlaskanWarrior
I suggest you read the report first. In this case radius does not equate to 40% of endurance.
AlaskanWarrior is quite correct. The terms "radius" and "range" are subjective, somewhat interchangeable, and not particularly relevant.
The game uses design "fuel miles" at "basis" to determine endurance. Full speed burns 6x the gas as cruise. There are only 2 speeds that apply; 'cruise' and 'full'. Mission speed is a calculated multiple of the two.
Well, according to the tables, that doesn't seem to quite jibe. Keeping equal values from the table - Radius, the cruise speed (15 Kt usually) R=8200. At 30 kt (usually what a TF would call Full speed) the R=2360 - that is a ratio of 3.47:1 vice 6:1. I don't think you can realistically use the Flank Speed indications for each ship as a factor in calculating the ratios because each ship would have a different Flank Speed, which means there wouldn't be much station keeping in formation. Some of the Treaty Battleships could only maintain only 26 kt Flank Speed on a regular basis for that matter. So that would limit formation speed to 25 kt at best to keep the BB's from looking like Old Smokey coming down the home stretch.
Which is why when I mod I use 20kts as cruise speed for most Allied warships. For the Japanese I use 18kts. WWII carrier ops, which were always being performed, were fuel hogs, especially when there is little wind or the wind was coming from the wrong direction.
RE: Ship endurance
Posted: Sat Nov 07, 2009 9:18 pm
by Mike Scholl
ORIGINAL: AlaskanWarrior
Which is why when I mod I use 20kts as cruise speed for most Allied warships. For the Japanese I use 18kts. WWII carrier ops, which were always being performed, were fuel hogs, especially when there is little wind or the wind was coming from the wrong direction.
You're actually being quite generous, as 12-15 knots more accurately reflects the speed at which most warships of the period obtain their best fuel economy.
RE: Ship endurance
Posted: Sat Nov 07, 2009 11:10 pm
by JWE
ORIGINAL: RevRick
Well, according to the tables, that doesn't seem to quite jibe.
Actually Rev, it jibes quite well, given this is, after all, an abstraction in which TF "cruise" is "cruise" for all ships regardless of their individual "cruise", and likewise "full", with the lowest being the fastest in both cases. The game is really looking at long term consumption rates.
A long term speed of "advance" for a CVTF is rather low, although, internally, tactical speeds may be quite high. Thus, the fuel burn rate might be lower than nominal for these. But there's only a few CVs, but a few thousand other ships, which have an arbitrary economical burn rate that is somewhat higher than nominal. So put all the different ship types, and all the different TF types and all the different mission types in a big pot - stir with a mother spoon - and take the integer of what comes up - and hey!! presto!! it looks a heck of a lot like what Gary Grigsby came up with 10 years ago.
Tables are nice; tables are pretty; tables are meaningless - unless they can somehow be related to game variables. And don't forget, we are not talking about "speed" per se, we don't have little ships in our computers. We are talking about a game variable that has a four-way implications.
You could, of course, increase warship "cruise", but then you would have to drastically decrease endurance (the table, remember?) but then a warship could never escort a merchie convoy, because it would "cruise" at the TF rate, but consume fuel at it's base rate, and could never cross the ocean on its own bunkerage. Just upping the "cruise" without reducing endurance is a joke, as we would all expect. And that is just a simple example.
Lots and lots and lots of factors come into play. I think it jibes pretty well, all things considered.
RE: Ship endurance
Posted: Sun Nov 08, 2009 2:30 am
by akdreemer
ORIGINAL: Mike Scholl
ORIGINAL: AlaskanWarrior
Which is why when I mod I use 20kts as cruise speed for most Allied warships. For the Japanese I use 18kts. WWII carrier ops, which were always being performed, were fuel hogs, especially when there is little wind or the wind was coming from the wrong direction.
You're actually being quite generous, as 12-15 knots more accurately reflects the speed at which most warships of the period obtain their best fuel economy.
Okay, I will give my reasons for why I choose to use higher cruise speeds.
First, I also adjust the endurance for 20kts. It is interesting that most of the ships will burn 5-6x the fuel at max speed that they burn at 20kts, which tells me that the original formula was pretty much right on, but the 15kt cruise speed was too low.
Second, higher AVERAGE fleet speeds were the norm for various reasons. Read any of the Friedman books on the design history of US warships. As it was understood then, the higher the speed the less chance of submarine interceptions and attacks. There are also other reasons. Likewise I have several sources that also state that the Japanese also realized the higher need for fleet cruise speeds, which for the Japanese was 18kts.
Third, task forces, convoys, etc rarely sailed in a straight line for any significant amount of time, thus the distance traveled hex to hex in the game is somewhat misleading. A Zig-Zagging ship will burn more fuel to go from point a-b.
Fourth, do not confuse peace time economical steaming with wartime steaming, which is anything but economical. Warships would operate in split plant mode to limit damage to engineering spaces, split plant mode is ineffecient. With the addition of more electronics, AA guns, and additional personnel to man them, the demand of ship electrical services was greatly increased. Electricity was primarily produced by steam driven generator, thus forcing more boilers to be online, thus decreasing endurance.
Fifth, the use of underway refueling greatly reduce the need for refueling stops at bases. It also meant that endurance was not necessarily a dominant aspect of ship design.
Sixth, the US designed ships from late-prewar on for endurance at 20kts, not 15, realizing that higher fleet speeds were going to me necessary.
There are other reasons, but these are the ones that come to mind.
RE: Ship endurance
Posted: Sun Nov 08, 2009 2:42 am
by akdreemer
ORIGINAL: JWE
You could, of course, increase warship "cruise", but then you would have to drastically decrease endurance (the table, remember?) but then a warship could never escort a merchie convoy, because it would "cruise" at the TF rate, but consume fuel at it's base rate, and could never cross the ocean on its own bunkerage. Just upping the "cruise" without reducing endurance is a joke, as we would all expect. And that is just a simple example.
Lots and lots and lots of factors come into play. I think it jibes pretty well, all things considered.
Conversely escorts were always running down the many false positives, usually going to full speed to reach the area of interest, thus increasing fuel expenditures. Which is why convoy escorts would refuel from a ship in the convoy. This was almost always a tanker (not AO) which was also rigged for underway refueling. I think the current game simulates this adequately
RE: Ship endurance
Posted: Sun Nov 08, 2009 9:20 am
by Dili
Since ships going at flank speed are usually in combat where there are maneuver and not optimal course it makes sense that it spends more than 3:1 vs cruise speed.
RE: Ship endurance
Posted: Sun Nov 08, 2009 5:05 pm
by JWE
Well, if you want to tweak stuff, here’s what it looks like. This is right out of the database. Included the Froude transition speeds as an indicator of efficiency. If you normalize the Froude transitions by SHP/Dspl ratio, lo and behold you end up with 12 – 16.
So you can clearly see the gift the game gives certain warships. And the gift to merchie hulls is pretty darn substantial. Only problem with tweaking warship cruise speeds is that they won’t match up (mathematically) with anything else. There is no game benefit for going slower than your ‘editor rated’ cruise speed.
Changing the paradigm is not a bad thing, but it must be done for everything and everyone in order to be realistic. The US and Brits aren’t that bad, but the Japanese need to have the Froude motive efficiency reduced by 8 – 12%. This, combined with the endurance reductions (fuel requirements) will push Japan into a ‘no gas’ mode in early ’44. Historical, yes, but against the AI, it would be in early ’43. Not a good option.
CV 3: rated max 31: cruise at 1/6 max consumption 18: Ft = 20.6
CV 6: rated max 31: cruise at 1/6 max consumption 16: Ft = 19.6
CV 9: rated max 31: cruise at 1/6 max consumption 15: Ft = 20.3
CVL 22: rated max 30: cruise at 1/6 max consumption 16: Ft = 17.6
CVE-9 on C3: rated max 18: cruise at 1/6 max consumption < 6: Ft = 15.6
CVE-55 on S4: rated max 19: cruise at 1/6 max consumption < 7: Ft = 15.9
CVE-105 on T3: rated max 19: cruise at 1/6 max consumption < 7: Ft = 16.7
BB 36: rated max 19: cruise at 1/6 max consumption < 10: Ft = 16.9
BB 38: rated max 20: cruise at 1/6 max consumption < 10: Ft = 17.2
BB 40: rated max 21: cruise at 1/6 max consumption 11: Ft = 17.6
BB 45: rated max 20: cruise at 1/6 max consumption 11: Ft = 17.6
BB 55: rated max 26: cruise at 1/6 max consumption 15: Ft = 18.9
BB 57: rated max 26: cruise at 1/6 max consumption 15: Ft = 18.3
BB 61: rated max 30: cruise at 1/6 max consumption 15: Ft = 20.8
CA 24: rated max 30: cruise at 1/6 max consumption 18: Ft = 16.9
CA 32: rated max 30: cruise at 1/6 max consumption 17: Ft = 17.1
CA 33: rated max 30: cruise at 1/6 max consumption 17: Ft = 17.4
CA 68: rated max 31: cruise at 1/6 max consumption 15: Ft = 18.3
CL 40: rated max 32: cruise at 1/6 max consumption 18: Ft = 17.3
CL 51: rated max 31: cruise at 1/6 max consumption 17: Ft = 16.3
CL 55: rated max 30: cruise at 1/6 max consumption 14: Ft = 17.3
Avg DD 348-364: rated max 31-34: cruise at 1/6 max consumption 18-21: Ft = 13.1
Avg DD 380-421: rated max 32-35: cruise at 1/6 max consumption 19-21: Ft = 13.1
DD 445: rated max 33: cruise at 1/6 max consumption 19: Ft = 13.7
DD 710: rated max 30: cruise at 1/6 max consumption 16: Ft = 13.9
RE: Ship endurance
Posted: Sun Nov 08, 2009 7:52 pm
by akdreemer
ORIGINAL: JWE
Well, if you want to tweak stuff, here’s what it looks like. This is right out of the database. Included the Froude transition speeds as an indicator of efficiency. If you normalize the Froude transitions by SHP/Dspl ratio, lo and behold you end up with 12 – 16.
So you can clearly see the gift the game gives certain warships. And the gift to merchie hulls is pretty darn substantial. Only problem with tweaking warship cruise speeds is that they won’t match up (mathematically) with anything else. There is no game benefit for going slower than your ‘editor rated’ cruise speed.
Changing the paradigm is not a bad thing, but it must be done for everything and everyone in order to be realistic. The US and Brits aren’t that bad, but the Japanese need to have the Froude motive efficiency reduced by 8 – 12%. This, combined with the endurance reductions (fuel requirements) will push Japan into a ‘no gas’ mode in early ’44. Historical, yes, but against the AI, it would be in early ’43. Not a good option.
CV 3: rated max 31: cruise at 1/6 max consumption 18: Ft = 20.6
CV 6: rated max 31: cruise at 1/6 max consumption 16: Ft = 19.6
CV 9: rated max 31: cruise at 1/6 max consumption 15: Ft = 20.3
CVL 22: rated max 30: cruise at 1/6 max consumption 16: Ft = 17.6
CVE-9 on C3: rated max 18: cruise at 1/6 max consumption < 6: Ft = 15.6
CVE-55 on S4: rated max 19: cruise at 1/6 max consumption < 7: Ft = 15.9
CVE-105 on T3: rated max 19: cruise at 1/6 max consumption < 7: Ft = 16.7
BB 36: rated max 19: cruise at 1/6 max consumption < 10: Ft = 16.9
BB 38: rated max 20: cruise at 1/6 max consumption < 10: Ft = 17.2
BB 40: rated max 21: cruise at 1/6 max consumption 11: Ft = 17.6
BB 45: rated max 20: cruise at 1/6 max consumption 11: Ft = 17.6
BB 55: rated max 26: cruise at 1/6 max consumption 15: Ft = 18.9
BB 57: rated max 26: cruise at 1/6 max consumption 15: Ft = 18.3
BB 61: rated max 30: cruise at 1/6 max consumption 15: Ft = 20.8
CA 24: rated max 30: cruise at 1/6 max consumption 18: Ft = 16.9
CA 32: rated max 30: cruise at 1/6 max consumption 17: Ft = 17.1
CA 33: rated max 30: cruise at 1/6 max consumption 17: Ft = 17.4
CA 68: rated max 31: cruise at 1/6 max consumption 15: Ft = 18.3
CL 40: rated max 32: cruise at 1/6 max consumption 18: Ft = 17.3
CL 51: rated max 31: cruise at 1/6 max consumption 17: Ft = 16.3
CL 55: rated max 30: cruise at 1/6 max consumption 14: Ft = 17.3
Avg DD 348-364: rated max 31-34: cruise at 1/6 max consumption 18-21: Ft = 13.1
Avg DD 380-421: rated max 32-35: cruise at 1/6 max consumption 19-21: Ft = 13.1
DD 445: rated max 33: cruise at 1/6 max consumption 19: Ft = 13.7
DD 710: rated max 30: cruise at 1/6 max consumption 16: Ft = 13.9
As usual throw techno babble at me..[:-] On the other hand increased fuel consumption forces the Allies into a more defensive posture for the first 6-9 months, which was also historical. It is very difficult to supply sufficient fuel to the South Pacific to operate more than a couple of carrier groups. The early war shortage of tankers and oilers, as well as refueling bases, gets emphasized when cruise speed increases and endurance decreases. I also adjust max speed and endurance values as ship refit to reflect added weight, etc. Play testing under WITP revealed this work well and gave a more historical feel to the naval operations.
RE: Ship endurance
Posted: Sun Nov 08, 2009 10:46 pm
by JWE
You are indeed in luck then. This is my last post on the Matrix open forums. So back to wikipoedia.
Have fun, good luck, and good bye.
RE: Ship endurance
Posted: Mon Nov 09, 2009 4:49 am
by stuman
" ...we don't have little ships in our computers "
Why didn't someone tell me ?