![]() |
Speed and quiet - 1/3 vs 2/3 vs full stop
I usually try to crawl around at 1/3rd (5 knots) but it is often too slow to maneuver into attack position. Just how loud are the U.S. subs when traveling at 10 knots (2/3rds)?
For example, say a Sturgeon skipper knows there is an enemy sub in the area. Will he slow down to 5 knots or will he feel safe continuing to cruise at 10 knots? Also, if I am comfortable where I am is it better to go full stop or would it be better to stay at 5 knots? Just wonder if full stop overs any advantages? |
It really depends on what the enemies are doing, what sensors they have, if you're in a duct, if there's a layer in between, etc. It is quite possible to stalk enemies up to 20kts if the variables are in your favor. Use the signature analysis to determine this. If engaging surface ships, observe their sprint and drift behavior, then use that to your advantage. Being stealthy does not necessarily mean being slow.
|
Quote:
https://www.youtube.com/watch?v=7CqCRNxIjbk |
Here's a nice tutorial from my buddy ramjb on why being stealthy doesn't mean you have to be slow.
https://www.youtube.com/watch?v=clhxFImfH9I |
Quote:
|
Basically, you've to use the Signature Analysis panel to gauge just how detectable you are versus a specific contact. As long as you're not over 10 dB on any enemy sensor at a given speed, you should be safe.
However, it's a gamble to run above 2/3 speed unless you're more or less certain the enemy won't be detecting you (i.e. you're in their baffles), considering the faster you go, the deafer you are. That can make you lose contacts and prevent you from noticing (and adapting to) changing circumstances. Which can very well happen given escorts and submarines occasionally change course and/or slow down to listen in where they couldn't earlier. Another thing to consider is that you can't measure yourself against what you haven't detected, so again, caution is advised unless you're fairly sure every enemy is accounted for. |
Aren't Narwhal and the 688's the only boats that have natural convection reactors that don't need to actively pump their coolant when running slowly? Is it modelled that they make a big step in quieting when going 1/3rd?
Also Rickover was a dick lol. |
Quote:
Perhaps it'll be a good idea to change the text file format to allow for aknot by knot noise value which the game just looks-up. Then we can program in however many kinks we feel is realistic. Pumps on/off, pumps switching to high speed, another pump being brought into the game, the raft being locked on some subs at high speed ... etc. |
Quote:
|
Quote:
|
Quote:
Would also be pretty cool if you could put the boat into turbo-electric mode or use the EPM. My understanding is that the EPM is pretty loud though. |
Quote:
|
I'm curious from an implementation standpoint - more a developer question - is noise level based more on reactor setting or knots?
So let's say we've got a Skipjack and a Sturgeon. Sturgeon is, by the game files, a quieter noise level boat. But is that at equivalent speed, or equivalent reactor setting? For example, both boats going 20 knots. Skipjack may only have to be at Standard to achieve this, Sturgeon at Full (just guessing, without verifying in game). Will the Sturgeon be quieter at equivalent speed? Or is that nullified by the fact that it's running at a higher reactor setting? |
Not to nitpick but it's more of a throttle setting than a reactor setting.
|
Quote:
The trouble is, this makes certain things (like the claims that the Alfa was actually a quiet boat until it was cranked up, or the "blade-rate" related noise suffered by the early Skipjacks and Permit class with 5 blade screws at certian speeds) impossible to replicate. What I'm not sure about is whether or not Silent Running will bring you below the base noise-level or just down to it, but other than that you'd have ownship noise + speed modifier. |
Quote:
There is enough thermal head to provide emergency cooling after a scram if the pumps have to be turned off. |
Quote:
With the EPM you are not going to be winning any speed races and you are VERY range limited but you will be a hole in the water. They tracked us by the LACK of noise in the water. We ran the range and then had to recover the plant and bring the boat back on-line quickly. It was quite the experience. It was QUIET in the engine room. Scary quiet. The outboard?? That would be for maneuvering in port. In theory you COULD use it to go somewhere if you have a propulsion train casualty, but that would be a LONG, LOUD, and SLOW. That was a screaming banshee as someone said earlier. |
This is something that is NEVER simulated correctly in any subsmin I have tried.
Basically the speed to noise curve is not a linear progression as it is always seemed to be modeled. This is going to be a very general discussion for obvious reasons. Here we go: You have to look at what is going on. The main noise you have on a boat is the propulsion plant in a nuclear powered vessel. It is the ONE thing that has to be on all the time. It is the single biggest creator of noise on the platform. Now, with the plant running critical sitting at the pier, you may be using 25% of your reactor power to just keep the lights on and such. We call the 'hotel load' It is a constant amount of power that is required to operate the various equipment on the boat. This means that the remaining 75% of the available power is used to turn the screw. A simplistic way to thing about speed is that each 'bell' is a doubling of power. Note that I did NOT say speed. Power is a cubed function in relation to speed. In essence, to double your speed you have to have 4 times the power to attain it. Here are some basic numbers: Ahead 1/3 is 5 knots Ahead 2/3 is 10 knots Ahead standard is 15 knots Ahead full is 25 knots Ahead flank is 30 knots If you worked BACKWARDS, ahead flank is 100% reactor output. That is all out get the hell out of dodge thermal limit on the plant. Ahead full is HALF of the amount of power, ahead standard is HALF of the power used for ahead full, and so on and so on. So what is the difference between ahead 1/3 and ahead 2/3? Not very much if you do the math. Now.. WHY is this important? Because you can increase your speed and have basically no increase in own ships noise up to a point. What you DO have is a degradation in your sensors to DETECT the other guy. So while he may still not be able to hear you, you lose the ability to hear HIM and thus you have to get even closer to detect him. The whole issue is about trading maneuverability and time for expediency. How much ocean can you cover and find the bad guy. I wish they had some kind of simplistic model of reactor plant ops. Give you, the captain, some kind of tactical option. You can go into an area in low power mode. You are quieter, but you are speed limited. You can go in at high power ops and while you are noisy, you have better acceleration and higher speeds. Make it so that if you have to shift to power states you make HUGE 'here I am' transients. That way you have to think about what you are doing and how you are going to approach things. Sorry for the ramble.. |
Ramble on! I was close-ish to going into a nuclear engineering program in college ~15 years ago, but opted the mechanical route instead. Interesting to hear the insight.
|
Yes, please ramble on haha. I do nuclear engineering for transport packages but I'm always interested to hear the reactor side of things. Isn't the power required to overcome drag proportional to the cube of velocity?
|
All times are GMT -5. The time now is 06:58 AM. |
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright © 1995- 2024 Subsim®
"Subsim" is a registered trademark, all rights reserved.