Senior Member
The only thing so far that I regret in as much as realism is converned behind fuel & engine tear and wear is actually the Flank speed setting (and discussed earlier by walkirie [in another thread]) the impossibility to accomplish makeshift repairs (jury-rigging) if for example damage occured to the diesel engines. Furthermore, using Flank speed can bring a new element of "dangerosity" to an already dangerous trip; intermittent and sporadic breakdowns and electrical surges among the most common. It did happen and unfortunately, these had not been modeled into the game. If they do not model this for the Add-on, then they are FAR away with what actually happened in the Indian Ocean.
Senior Member
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Junior Member
I have seen the bug impact me in that I do what others have done. Full/Flank from Pearl to Midway and then 2/3 (11-12 knots) to Honshu. Getting to my patrol station at roughly 75/100 fuel used (hadn't checked the actual count but the meter showed a 1/4 tank used).
I then patrol and used my torps up and went to leave for Midway with 67/100 fuel (I did check that). I then used the same speed setting (2/3, 11-12 knots) to get back to Midway and found that I ran out of fuel at least a Day out from Midway.
Weather, checked at various points, did not seem to be a factor.
I also, as has been discussed before, experienced the issue where time compression was useless past 512x for whatever reason (I suspect this is related to me spotting, but not sinking, various ships in the harbor areas I patrolled past).
But I tried repeatedly (and this takes some time at only 512x speed) to get from the coast of Honshu back to Midway at 2/3 speed and ended up short each time (still starting at 67/100 fuel left).
So, I have some idea of trying to use econmical fuel burning speeds and yet ran into this patrol where that was of no real use. I know that some bug exists that keeps that from working as intended.
Most patrols I have had no issue with using this same 'scheme' of getting to my last refit point asap, then proceeding to my patrol point at 2/3 speed to conserve fuel, then returning the same way.
This last patrol was far different howerver.
I am confident there is a bug, but can't say for sure what causes it, that makes the fuel consumption run outside of what is intended.
Senior Member
Senior Member
Rule of thumb, if it takes you half a tank to get where you are, it will take half a tank to get you home. If you are still loaded with torps, so be it. The game bases your grade on making the assigned areas and patrolling it for the time it tells you too. If you nail a few vessels, then more the better for you.
Senior Member
Ok, this is not rocket science, and there is no fuel bug.
- Fuel expenditure is based on how many RPMs your engines are turning. The more RPMs, the faster the rate of fuel consumption.
- In reality, in code, you only have TWO engines, because the underlying mechanics are derived from Sh3.
- While recharging your batteries, one of these engines is running at an RPM equivlant to flank speed.
- If you combine battery recharge, with normal patrolling, that means you have one engine running at MAX RPM, and another running at 2/3rds RPM or what have you while your cruise around. Combine the two, and this is your total fuel expenditure during a battery recharge.
- Battery recharges in Sh4, are NOT the 3 hours or so in Sh3. More like 6 or 7 hours. If your used to stretching your range by using your batteries more and engines less, in SH3 you could do this. In SH4, you cannot. If anything Sh3 had a "Bug", and the devs corrected it in Sh4. A battery recharge does not last 3 hours, but more like 6 or 9 hours, which Sh4 reflects. What this means is you have one engine running at flank speed for 6 or 7 hours where in SH3 you might be used to just 3 hours. In short, battery recharges, take twice as much fuel to accomplish then in Sh3. The moral of this point, is that one should conserve their batteries.
- rough weather effects your top surface speed. Moreso in Sh3, then in Sh4, but it is still a factor. Meaning that for example while ahead 2/3rds worth of RPM may have gotten you 9 kts in a calm to moderate sea- in a 15 kt wind, it may only produce 7 or 8 kts. The distance your covering is reduced for that given RPM, hence your max distance will be less.
- The fact of the matter is, planning your fuel expenditure, is a intergral part of this game. You are the captain, and theres a little bit more to it then saying, "up periscope" and "Fire!". You must plan your route. If you see your patrol order, it is up to you to plot how far it is from your current position, mulitply it by 2 to get your round trip.
Bah, heres an example.
Lets say i have to patrol the bungo straights. Ok, i leave port, and the first thing i do, is hit midway to top off the fuel tanks. There is no excuse not to.
From there, what ill do is plot the distance from midway to my patrol area. Lets say its 4,000 NM. (bogus number). Ok so i know that i'll be using 8,000 NM's worth of fuel, JUST to get there and back. This number is non negotiable. So that means if my total fuel is 15,000 NMs @ 10 kts worth, then i have 6,000 NM's worth of fuel to acutally operate with. Then ill plan for a backup allowance(to plan for rough weather or what have you), of say mabye 1000, to 2,000 NM. that means i have 4,000 NM worth of fuel to hunt japs with. This 4,000 NM is what is what i refer to as my "operational allowance". Its all i have, 4,000, and i use it wisely by conserving my batteries, and by plotting positions using the speed range chart to see what targets are feasible to puruse, and at what speed i can minimally use, and still overtake them and get a fireing position.
If your just running out there and hitting flank, and not being prudent, then yeah your going to run out of fuel.
Senior Member
Thats a good summary Ducimus
What i still dont like about SH-IV is that you sometimes get illusoric mission orders. For instance : I was based in Pearl Harbor and got the order to patrol a area in the East China Sea.
Meaning that i had to use a immense portion of my fuel to reach this area. (Even with only 8 knots)
As the job was finished i got the order to patrol the Celebes Sea.
Needless to mention that this was logically not possible as i dont have enough fuel to go there and reach any allied base afterwards. (Even when i would just travel through without a single day of patrol)
This, of course, brings us back to the old topic "Refuel at sea" that caused heated discussions in the old days at the SH-III forum.
In reality, u.s subs did not travel at slow 8 knots through the pacific to reach their operation areas with one load of fuel they recieved in the base.
They mainly travelled at much higher speeds as this was often simply required by the circumstances of war. There was simply no time to pleasure cruise for half a month to the operation area. They mainly had to get there ASAP and often even "yesterday" as intelligence informations wear out in hours or days instead of weeks or months.
The higher fuel consumptions got countered with pre-planned refuel operations at sea along the course to their operation areas.
You just dont have this in SH-IV which is often very frustrating, especially in such a big ocean as the Pacific.
I know that it requieres a unbelievable and maybe almost impossible complex effort to get a dynamic refuel system into a dynamic campaign but at least it must be possible to get pre-planned and therefore non-dynamic refuels to your first mission objective if its really far away.
The war is over before you cross the entire Pacific with only 6 knots to your patrol area and back
Senior Member
The mechanics of range vs speed is limited by the game engine really. You could for instance, change the numbers in the sub file to be 15,000 NM @ 12 kts. or even 14 kts. (which was probably "2 engine speed") Ive often thought of this, the main reason i do not, is because
a.) It can be abused by a knowledgable player who can really stretch their range far beyond realistic values.
b.) Id have people critizising me for being what they deem as unrealistic. Thats just the ugly beast that is modding.
Now there is ONE bug that i know of that can reduce your range if your not observant. If your batteries get damaged, the game wont automatically turn off recharge mode when the charge is complete. If your not observant and don't catch this, you'll swear you have a fuel leak or something.
Senior Member
Sadly, the US submarines didnt have the UnRep (Underway Replenishment) option that the U-boats had. Their UnRep was forward bases such as Midway and Darwin. K_Freddie also had a point. Fleet boats were able to use their ballast tanks as additional fuel tanks. Dunno if its modeled in the game. It should be, but not sure if it is. Also, some skippers (O'Kane in particular), would sit in a spot, with the engines off, for hours. This would allow the sonarman to get a good reading at what might be around. Also, while a skipper might run 15 knots to get somewhere quicker, he's gonna be running 7-8 knots later to account for the extra fuel.
. This could be a reason for the increased fuel usage in one direction and less in the other. if so, one would have to change the return route !!
