optimum speed for Subs?

[steinbeck]

On my 1st patrol to Bashi Channel.

Installed mods:

1_TriggerMaru_Overhaul_2-5
RSRDC_TMO_V502
RSRDC_V5xx_Patch1
1.5_Optical Targeting Correction 031312 for RSRDCv502
1.5_OTC_Realistic Scopes for 16 to 9 RSRDCv502
Improved Ship Physics 2.6_TMO_RSRDC_OTC
OTC_ISP_Crew Mod
1.5_OTC_UIS Radar from Start for TMO
FJB Two Tone Navigation Map
Historical Prop Rotation
Midway Career
NSM4 Classic
TMO_Visuals_for_RSRDC
Traveller Enhabced Soundsv 1.0
Webster's Better Mouse Arrows for 1.4 and 1.5
Webster's No Crew Fatigue for 1.4 and 1.5

The problem is fuel?
So far I have travelled from Midway, 2.515.5nm.
To reach Bashi Channel: still to travel, 1.471.6 = total of 3.987.1nm

Fuel left in tanks 51% So for a 1/4 of a tank I've travelled 1.257.75

I cannot get on station, patrol for 72 hours and be able to return to Midway.

What is wrong ? I cannot see any of the mods causing this! Or do I get back with fumes in the tanks?

[SilentPrey]

Optimum speed is around 10 knots. With ISP I set the telegraph to 2/3 for transit and 1/3 for patrolling. If you're short of fuel on your way back set 1/3. ISP has your sub influenced quite a bit by weather and some by crew efficiency. When set to Standard you may not be making more than 11 or 12 knots but you're calling for more and burn at the higher rate. (I want to say standard will give you 16 or 17 knots on flat seas with an efficient crew.)

[steinbeck]

Odd that. At one time it was 'ahead standard' the most efficient speed for cruise.
I'll try a new start and cruise at 2/3 although with my older set of mods I was fine to get there and back.

What is meant by ISP?

[merc4ulfate]

Improved Ship Physics 2.6_TMO_RSRDC_OTC = ISP

I normally run the TMO small patch after TMO and before any other mod ... it will avoid the Terrible T issue.

[TorpX]

Originally Posted by steinbeck

On my 1st patrol to Bashi Channel.



What is wrong ? I cannot see any of the mods causing this! Or do I get back with fumes in the tanks?

You didn't say what class of boat you have.

If it is a Porpoise, I would pick a patrol zone closer to you.

The Porpoise had a range specification of 6,000 nm @ 10 kn. It's successors had 11,000 @ 10 kn.

In any case, these are the optimum speeds of the boats:

About fuel consumption in transit: I found fleet boats got the best mileage at ~9 knots, the S-class at ~6 or 6½. Remember, it is the engine speed, not the telegraph setting, that is important. This was with ISP, mods with different engine values may be different. Economical speed is ~3 kn. submerged.

Fleetboats use fuel while sitting still on the surface idling. I found the fuel burned was equivalent to going 9 kn. or so. This seemed outrageous to me, so I put a workaround for this in ISP. Then, you could lay to, and save fuel while you waited for a contact to show up. S-class boats don't burn fuel, at all stop.

Obviously, recharging batteries consumes fuel.

At one time it was 'ahead standard' the most efficient speed for cruise.

This certainly isn't true with ISP, and I don't know where this idea came from, tbh. It really doesn't make sense. Best mileage will be at one engine speed, which is 'Ahead 1/3' in ISP. The game doesn't care about telegraph settings; you could make 1/3 100% of your max. speed, if you wanted, but it doesn't change your mileage. 9 knots will still get you farther, whether you call it 1/3 or something else. To put it another way, the engine telegraph settings are a matter of convenience. They don't change the engine workings.

I think people have confused the idea of 'best speed', meaning best mileage, and 'best speed' being the fastest speed, that permits reaching your goal, and fulfilling your mission.

[Sailor Steve]

TorpX, I agree with you completely. I'm just using your comments to elaborate and expand.

Originally Posted by TorpX

Obviously, recharging batteries consumes fuel.

Absolutely true. Steinbeck, I can understand your outrage, especially since SH3 made it so submerging and then recharging extended your range. In actuality the engine that is doing the recharging is doing so at full speed. it burns more fuel than just staying on the surface. Outrageous or not, it is accurate.

This certainly isn't true with ISP, and I don't know where this idea came from, tbh.

It comes from TMO. Ducimus argued that since the surface fleet cruised at 15 knots and the big American subs were called "Fleet Boats" because they were expected to cruise with the fleet, then Ahead Standard should be the norm. What gets left out is that the surface fleets refueled at sea constantly. Fuel didn't matter, speed did. Fleet-type submarines were indeed designed to operate under those conditions, but never actually did.

It really doesn't make sense. Best mileage will be at one engine speed, which is 'Ahead 1/3' in ISP. The game doesn't care about telegraph settings; you could make 1/3 100% of your max. speed, if you wanted, but it doesn't change your mileage. 9 knots will still get you farther, whether you call it 1/3 or something else. To put it another way, the engine telegraph settings are a matter of convenience. They don't change the engine workings.

Within reasonable bounds the slower you go the less fuel you use. Your car gets better mileage at 35 mph than it does at 65. That's fine on paper, but do you really want to take 20 hours for a cross-country drive instead of 10? It's a compromise. You use the speed that will get you to your patrol zone the fastest and still use the least fuel. Too slow and it takes longer to get there than it's worth. Too fast and you might not get back.

[SilentPrey]

Originally Posted by merc4ulfate

Improved Ship Physics 2.6_TMO_RSRDC_OTC = ISP

I normally run the TMO small patch after TMO and before any other mod ... it will avoid the Terrible T issue.

Yes. However, the small patch gets overwritten with this configuration. I believe it is OTC. When using the small patch the way you describe I ended up getting 'upgraded' from a Gato to a Tambor. So I incorporated the small patch fix into the OTC_ISP_Crew Mod.

[steinbeck]

So I wasn't dreaming,that 'Ahead standard' was the best cruising speed!

Anyway, I've adopted the 2/3rds etc and it seems to be ok so far.

Amazing how out of touch one gets after a 5 year absence.

Jusat wish I coulds get SHIII to work on my Win & rig. Installs from my old disk, even bought a new?? one which turned out to have the same problem. Some Microsoft message, but unable to find any solution. Still got my Grey Wolves mods etc . Very disappointing.

[Sailor Steve]

First question: Is it installed to Program Files? If so, make a folder outside of Program Files and move or install it there. That may or may not solve the problem but it's an accepted problem that newer versions of Windows don't like you putting things there.

I run SH3 on Windows 8.1 with no problems at all.

[CaptBones]

Not to throw a wrench into the works or dampen anyone's enthusiasm...

But, trying to apply real world logic/facts/figures into the simulations we're playing here is not always particularly useful, really. The SH4 game engine, derived from the SH3 engine, simulates a U-boat mechanical/electrical propulsion drive system. It's not even close to the US "Fleet" boats' diesel-electric drive system...not even in the ballpark, totally incorrect. To start with, those boats not only had four diesel-generator sets for main propulsion, but also from one to three auxiliary/emergency diesel-generator sets that could provide all ship's service electrical power, charge the batteries, or drive the propulsion motors just as well as the main DG sets could, but achieving a much slower speed. Yes, the design performance characteristics are useful in attempting to get the simulated submarines to behave as "realistically" as possible. But even there I would suggest the word "accuracy" is more correct than "realism" (which is something that IMHO applies to everything in the world of computer games/simulations...the "realism" involved in sitting at a computer playing games/simulations is 0%).

One of the comments made about the meaning of the term "Standard Speed" is quite correct. Ships, warships especially, are designed to meet a broad spectrum of specified performance requirements. Standard Speed is exactly that...a speed (with a specific propeller turn-count) to meet tactical maneuvering requirements, including turn-rate, Advance and Transfer, and Tactical Diameter of turns, in order to be able to safely maneuver in a Formation of other ships, including different Types and Classes. In the USN, prior to WWII as well as now, that speed was 15 kts, at "Full Load" displacement, with excess shaft HP to allow for bottom fouling. Making turns for Standard Speed with a clean bottom and/or at "Light Load" displacement, would typically provide for 16-17 knots or possibly even more, depending on weather and sea-state. For the "Fleet" boats, which were designed to operate with the Fleet, the variable of being able to change the ship's surfaced draft was an added dimension that just serves to make the problem in our game engine(s) even more difficult. Preparing for conducting Full Power Trials and Economy Trials always includes correction of the required turn-count based on draft and bottom condition. USN Economy Trials are always run at 15kts "through the water" (as differentiated from "over the ground").

The propulsion plant is designed to provide for "economical" cruising at that same speed. Here, the key is something that also has been mentioned before in this and other threads on SubSim forums. Standard Speed is the "economical" speed for a warship, but does not necessarily mean the most fuel-efficient speed; it's a combination of time and distance. If you are lolly-gagging around taking your merry time to get someplace where you're supposed to be, you'll find yourself being relieved of Command in short order.

Tweaking the game files to achieve 100% "realism" in propulsion plant performance is impossible. It would require a super-computer to do that and that is beyond the financial means of any/all of us...we had one (or two) of those at NAVSEA and used them to make 100% accurate models of ships and ship propulsion plants. Even then, Trials with real ships seldom produced the same results as our simulations. The most powerful computers still can't match Mother Nature's weather and other variables, environmental and man-made.

Anyway...not to throw a wrench into the works or dampen anyone's enthusiasm...we do need to use whatever tricks and tweaks that can be done to ensure that our boats can get to their assigned Patrol/Special Mission areas with enough fuel to complete the mission and get back home again. Whether a needed Mod/tweak increases the fuel capacity to ridiculous amounts or ridiculously improves propulsion plant efficiency probably doesn't matter. I would simply finish by suggesting that nobody get too wrapped up in trying to achieve 100% "realism" or accuracy, because it's never going to happen here.

Oh, there is one other thing. My wish list includes a fix for the incorrect engine orders and the completely incorrect rudder angles. We hear "Ahead Slow" for the Ahead 2/3 engine order telegraph setting. There is no "Ahead Slow" engine order in the USN...Ahead 1/3 is ahead slow (or slow ahead if you prefer). The use of 40 degree "standard" rudder is ridiculous, in any Navy. You're putting the rudder into the stops at 40 degrees, which is a good way to jam the rudder hard over. Depending on the design of the ship and the desired performance characteristics, "Standard" rudder is typically 15-20 degrees; "Full" rudder is usually 25-30 degrees and "Hard" rudder is normally 5 degrees less than putting the ram(s) into the stops. Instead of fixing the hydrodynamic drag for a 40 degree "standard" rudder, couldn't we change the normal rudder angle used to 20-25 degrees (and then tweak the turn rate & etc.)?

[steinbeck]

Originally Posted by Sailor Steve

First question: Is it installed to Program Files? If so, make a folder outside of Program Files and move or install it there. That may or may not solve the problem but it's an accepted problem that newer versions of Windows don't like you putting things there.

I run SH3 on Windows 8.1 with no problems at all.

I am not quite sure now, I believe it installs into C:\\Programme Files(x86). I can easliy be moved if that will cure it. I had forgotten the quirky C:\\Drive. I keep my games on my E:\\ Storage drive. which is a big one.

Thank You, I'll look back at an install and see what transpires.

[Sailor Steve]

Originally Posted by CaptBones

Not to throw a wrench into the works or dampen anyone's enthusiasm...

Excellent summary of the problems involved in real-world ship command.

If you are lolly-gagging around taking your merry time to get someplace where you're supposed to be, you'll find yourself being relieved of Command in short order.

Tell that to Admiral Frederick Charles Doveton Sturdee. When tasked with intercepting and destroying Admiral Maximilian von Spee's squadron in 1914, Sturdee took his time getting to the Falkland Islands, stopping and inspecting every merchant ship he saw along the way, spending extra days in port at various islands and generally not being in a big hurry. Of course luck was with him as this put him in Port Stanley exactly in time for the attack on that harbour by Spee's group. Had he hurried as he should Sturdee would likely have missed Spee altogether and looked like a fool, which is what his superior First Sea Lord Jacky Fisher apparently hoped would happen. Instead Sturdee became the first British naval hero of the First World War.

I know, "Exception that proves the rule", "If you can't be good be lucky," "Do as I say, not as I do", and all that.
Sorry, couldn't resist. I'm just sayin'

Oh, there is one other thing. My wish list includes a fix for the incorrect engine orders and the completely incorrect rudder angles. We hear "Ahead Slow" for the Ahead 2/3 engine order telegraph setting. There is no "Ahead Slow" engine order in the USN...Ahead 1/3 is ahead slow (or slow ahead if you prefer).

I hate that too. I also hate the whole "Yes, Sir!" business. I've been planning for years to make a sound mod for SH4 that would fix all those, conforming to the way it was done in SH1. I've already done a little speech fix for my DBSM translation for OM. I'll try to remember to look into doing as small speech mod that just addresses those two glaring mistakes.

The use of 40 degree "standard" rudder is ridiculous, in any Navy. You're putting the rudder into the stops at 40 degrees, which is a good way to jam the rudder hard over. Depending on the design of the ship and the desired performance characteristics, "Standard" rudder is typically 15-20 degrees; "Full" rudder is usually 25-30 degrees and "Hard" rudder is normally 5 degrees less than putting the ram(s) into the stops. Instead of fixing the hydrodynamic drag for a 40 degree "standard" rudder, couldn't we change the normal rudder angle used to 20-25 degrees (and then tweak the turn rate & etc.)?

I hate that as well. Unfortunately I have no idea how to change that.

[TorpX]

The use of 40 degree "standard" rudder is ridiculous, in any Navy. You're putting the rudder into the stops at 40 degrees, which is a good way to jam the rudder hard over. Depending on the design of the ship and the desired performance characteristics, "Standard" rudder is typically 15-20 degrees; "Full" rudder is usually 25-30 degrees and "Hard" rudder is normally 5 degrees less than putting the ram(s) into the stops. Instead of fixing the hydrodynamic drag for a 40 degree "standard" rudder, couldn't we change the normal rudder angle used to 20-25 degrees (and then tweak the turn rate & etc.)?

I had wondered about the 40° rudder thing.

The game 'crews' will always use the full 40, if left to their own devices, and the turn is more than ~20°. I don't think there is any way to change it. AFAIK, nobody has been able to change basic AI elements in this game.

[CaptBones]

Thanks TorpX...as Ralphie said..."Oh f-u-u-u-u-dge!" I suspected the rudder problem was a tough nut to crack, but hoped that someone with your skills might have been looking into it. Maybe the changes you made in ISP are "close enough"...at least reducing the drag and fixing the turning radius; eh? I have just started using ISP2.6 for TMO_RSRD and would be happy to share my thoughts on the new behavior of the "Silversides" after I get a patrol or two under my belt...if you want those thoughts, that is.

Sailor Steve...oh, three cheers if you do fix that annoying "Yes Sir" bugaboo. I think I would have had any helmsman keelhauled for answering a conning order that way. Even the OOD, or JOOD if he had the conn, and/or the Diving Officer, would never think of responding that way to the CO's instructions for a course change, speed change, etc.

I suspect the difficulty you will have in making such a fix, will be to determine whose order the voice is responding to. The game scenario seems to be always based on the player, as the CO, having the conn and/or the dive. So, the proper response from the helm/lee helm and/or planesmen would be to repeat the order and add "...aye Sir." But, the double-repeat that I'm hearing is indicative of the CO giving his instructions to the OOD/Diving Officer and those orders then being passed on to the helm/lee helm and/or planesmen. Makes it a more difficult problem to get it 100% accurate (notice I did NOT say "100% realistic").

Anyway, thanks for the comments and best of luck to ya'...

[TorpX]

Originally Posted by CaptBones

Thanks TorpX...as Ralphie said..."Oh f-u-u-u-u-dge!" I suspected the rudder problem was a tough nut to crack, but hoped that someone with your skills might have been looking into it. Maybe the changes you made in ISP are "close enough"...at least reducing the drag and fixing the turning radius; eh? I have just started using ISP2.6 for TMO_RSRD and would be happy to share my thoughts on the new behavior of the "Silversides" after I get a patrol or two under my belt...if you want those thoughts, that is.

I do think ISP gives a big improvement to turning. That's not to say it is perfect, but certainly better.

Subs' turning radii is about the same (according to sources I had, as it should be), but speed loss is much less now.

Ships, I greatly reduced rudder drag. Ships like DE's, kaibokans, and small craft can turn tighter; big ships BB's, CA's, large merchants, turn slow, but also lose less speed.

I could not prevent constant-helming behavior, but at least they will not slow down so much.

I used figures for the HMS Hood, supplied by Sailor Steve, to adjust large ships. I was able to get a very close match for the timing and speed loss (and by implication the turning circle). I didn't have detailed info for most ships, so I adjusted them on a type by type basis. I wanted to post figures for this, but I seem to have lost them.

...three cheers if you do fix that annoying "Yes Sir" bugaboo.

I would add to this, the oft repeated 'gun loading', and 'depth 20 feet' entries that don't really tell me anything useful, but crowd out potentially useful log info. For example, it is nice to be able to go back and see at 1946 you ordered course 345°. Unfortunately, there is no entry when the crew turns to reach the next waypoint; kind of a flaw, imo. As well, an automatic update of log for weather changes would be helpful.